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Plants Poisonous to Livestock in Montana and WyomingConsiderations for Reducing Production Losses
Natural Resources Conservation Service Plant Matrials Technical Note MT-124
Montana State University ExtensionUniversity of Wyoming Extension Bulletin B-1359
AcknowledgementsPlants Poisonous to Livestock in Montana and Wyoming represents a cooperative effort among individuals within the United States Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS), Montana State University (MSU) Extension, and University of Wyoming (UW) Extension. This publication is adapted with permission from Poisonous Range Plants of Montana (Leininger et al. 1977) and Plants Poisonous to Livestock in the Western States (Panter et al. 2011). We acknowledge and thank previous authors for those documents and contributions to this field of study.
Contributors (alphabetical order)Haylee Barkley, USDA-NRCS, Pathways Program, Bozeman, MTKaren Clause, USDA-NRCS, Range Management Specialist, Pinedale, WYJane Mangold, Ph.D., MSU, Professor and Extension Invasive Plant Specialist, Bozeman, MTTed Nelson, DVM, USDA-NRCS, Supervisory District Conservationist, Livingston, MTNoelle Orloff, MSc, MSU, Associate Extension Specialist, Bozeman, MTMonica Pokorny, MSc, USDA-NRCS, Plant Materials Specialist, Bozeman, MTDerek Scasta, Ph.D., UW, Assistant Professor and Extension Rangeland Specialist, Laramie, WYBarton Stam, MSc, UW, Range Extension Educator, Thermopolis, WYSusan Tallman, MSc, USDA-NRCS, Area Agronomist, Bozeman, MTDaniel Tekiela, Ph.D., UW, Assistant Professor and Extension Specialist of Invasive Plant Ecology, Laramie, WY
We express our appreciation to the following reviewers:Daniel Cook, Ph.D., USDA-ARS Poisonous Plant Research Laboratory, Research Plant Physiologist, Logan, UTMarko Manoukian, MSU, Phillips County Extension Agency, Malta, MTJennifer Paddock, USDA-NRCS, District Conservationist, White Sulphur Springs, MTJ. Daniel Rodgers, Ph.D., UW, Associate Professor and Extension Rangeland Specialist (retired), Laramie, WYJoseph Scianna, USDA-NRCS, Plant Materials Center Manager, Bridger, MTClinton Stonecipher, USDA-ARS Poisonous Plant Research Laboratory, Range Technician, Logan, UTKevin Welch, Ph.D., USDA-ARS Poisonous Plant Research Laboratory, Research Toxicologist, Logan, UT
Suggested citation:USDA-NRCS, MSU, and UW. 2020. Plants Poisonous to Livestock in Montana and Wyoming, Considerations for Reducing Production Losses. USDA-NRCS Plant Materials Technical Note MT-124 and University of Wyoming Extension Bulletin B-1359. USDA-NRCS, Bozeman State Office, Bozeman, MT. 43 pg.
This publication is available electronically (free) and in hard copy from the NRCS Montana and Wyoming Plant Materials Program, Montana State University Extension, and University of Wyoming Extension websites.
Cover photos:Front top and bottom left: lupine (Lupinus sp.) and poison hemlock (Conium maculatum), M.Lavin, MSU; Front bottom center and bottom right: larkspur (Delphinium sp.) and milkvetch (Astragalus sp.), USDA-NRCS. Back top and center: poison hemlock (Conium maculatum) and foxtail barley (Hordeum jubatum), M. Lavin, MSU; Back bottom: deathcamas (Zigadenus venenosus), T. Nelson, USDA-NRCS.
In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender expression), sexual orientation, disability, age, marital status, family/parental status, income derived from a public assistance program, political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all bases apply to all programs). Remedies and complaint filing deadlines vary by program or incident.
Persons with disabilities who require alternative means of communication for program information (e.g. Braille, large print, audiotape, American Sign Language, etc.) should contact the responsible Agency or USDA’s TARGET Center at (202) 720-2600 (voice and TTY) or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in languages other than English.
Table of Contents
TABLE 1. Signs of poisoning and conditions under which plant species can be dangerous to livestock. Symptoms listed for each plant are those most likely to be observed. Not all symptoms will be seen in all toxicities, and signs of poisoning may vary greatly depending on dosage and the time taken to consume the dose. Also, individual animals respond differently to specific toxins. ....... 21
TABLE 2. Toxic doses for commonly diagnosed plant poisonings in Montana and Wyoming. For some plant species, signs of livestock poisoning may not be evident until a toxic threshold is reached. ....... 31
TABLE 3. The origin and habitat of plants with toxic properties in Montana and Wyoming. ...............................34
INTRODUCTION ........................................................................................................................................................4 Economic Impacts of Poisonous Plants .........................................................................................................4 Identifying Poisonous Plants .........................................................................................................................5FACTORS INFLUENCING PLANT TOXICITY FOR LIVESTOCK ...........................................................................6 Plant-related: ..................................................................................................................................................6 Dose ........................................................................................................................................................6 Season and Plant Growth Stage .............................................................................................................6 Palatability ..............................................................................................................................................7 Growing Conditions ...............................................................................................................................7 Component of Hay ..................................................................................................................................7 Animal-related: ..............................................................................................................................................8 Animal Species, Gender, Size and Age ..................................................................................................8 Animal Health ........................................................................................................................................8 Animal Response to Toxin .....................................................................................................................8CONDITIONS LEADING TO LIVESTOCK POISONING AND MANAGEMENT TO REDUCE IMPACTS ..................................................................................................................9 Grazing Rangeland and Pasture that Are in Poor Condition .......................................................................9 Hungry Animals on Infested Rangeland, Pasture or Cover Crop ................................................................9 Early Season Grazing on Rangeland .............................................................................................................9 Livestock Familiarity with the Area ............................................................................................................ 10 Improper Herding, Driving and Bedding.................................................................................................... 10 Inadequate Nutrient Supply..........................................................................................................................11 Water Quantity and Quality .........................................................................................................................11 Environmental Conditions ...........................................................................................................................11 Cultural Practices ........................................................................................................................................ 12 Grazing System ............................................................................................................................................ 12 Multi-species Grazing .................................................................................................................................. 13 Crop and Cover Crop Grazing ...................................................................................................................... 13CARE FOR IMPACTED ANIMALS .......................................................................................................................... 13CONTROL OF POISONOUS PLANTS ...................................................................................................................... 13POISONOUS SUBSTANCES AND OTHER FORAGE PROBLEMS ........................................................................ 14PRINCIPLE TOXINS ................................................................................................................................................14 Alkaloids ....................................................................................................................................................... 15 Cardiac Glycosides ....................................................................................................................................... 15 Cyanogenic Glycosides ................................................................................................................................. 16 Nitrate........................................................................................................................................................... 16 Oxalates .........................................................................................................................................................17 Saponins ....................................................................................................................................................... 18 Selenium ....................................................................................................................................................... 18OTHER FORAGE PROBLEMS AND DISORDERS ................................................................................................. 19 Bloat .............................................................................................................................................................. 19 Mechanical Injuries ..................................................................................................................................... 19 Mycotoxins ................................................................................................................................................... 19 Photosensitization ........................................................................................................................................20 Volatile Oils ..................................................................................................................................................20RESOURCES AND REFERENCES ..........................................................................................................................40GLOSSARY ..............................................................................................................................................................42
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IntroductionPoisonous plants contain or produce substances that cause sickness, metabolic disorders, death, or health concerns in animals when ingested. Each year these plants adversely affect 3 to 5% of the cattle, sheep, goats, and horses that graze western United States rangelands, pasture, and forest lands. There are many plants in Montana and Wyoming that have been suspected of being poisonous. However, these plants vary in their toxicities, the types of animals affected, and the environmental conditions when poisoning occurs. For example, a plant species might provide good forage for sheep yet be poisonous to cattle and horses. Another plant may provide excellent nourishment in small amounts or during certain seasons but be poisonous under different conditions.
Poisonous plants will always be present on rangeland, pasture, and forest lands, and may be intentionally planted as cover crops or forages on croplands. Many poisonous plants are native to Montana and Wyoming and naturally occur in plant communities. Other poisonous plants are introduced (i.e. non-native) species, and some of these introduced species are invasive and spreading across the region. Mismanagement of rangeland and pasture can allow these introduced and native poisonous plants to increase since some of them are unpalatable. Additionally, poor livestock management may increase the likelihood of poisoning. Rangeland and pasture should be regularly inspected for poisonous plants and the information used to make prudent livestock and grazing management decisions.
Wild onions (Allium sp.) are native plants that emerge in the early spring in a variety of plant communities. Livestock can exhibit poisoning effects if their diets contain large quantities (e.g. 25% diet) of onion leaves.
Black henbane (Hyoscyamus niger)1, an introduced invasive species from Europe, can increase with poor pasture management. Its foliage has a pungent odor and is not usually consumed by livestock unless desirable forage is lacking. When consumed, symptoms of poisoning include dilated pupils and convulsions.
1 Nomenclature, common and scientific names, follows USDA PLANTS Database, 2019.
This publication describes signs of poisoning and livestock affected (Table 1), toxic doses and factors influencing toxicity (Table 2), and the habitats where these poisonous plants grow in Montana and Wyoming (Table 3). The publication also describes environmental and management conditions leading to livestock poisoning along with management considerations to prevent or minimize impacts.
Economic Impacts of Poisonous PlantsPoisonous plants cause an economic loss to the livestock industry. In 1992, the economic value from direct losses of cattle and sheep in the 17 western states was $340 million dollars, which would exceed $600 million today when adjusted for inflation. In addition, there are indirect economic impacts from poisonous plants associated with increased management costs.
Direct impacts include the following effects on animals:• Death• Abortions• Birth defects• Weight loss due to illness or decreased feed intake• Lengthened calving interval• Decreased fertility• Decreased immune response• Increased organ damage (e.g. lungs, liver, nervous
system, etc.) • Loss of breeding stock due to mortality, functional
inefficiency, etc.
Photo: USDA-NRCS
Photo: USDA-NRCS
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Identifying Poisonous PlantsThere is no single rule or characteristic that can be used to determine a toxic plant from a non-toxic plant. To protect animals from poisoning, learn to identify poisonous plants that are common to the area and obtain reliable information on their poisonous properties. Some poisonous plant publications focus on plant identification; however, this publication does not because plant identification resources are readily available. We provide a list of resources to aid in identification in the Resources and References Section below.
Sudden onset of illness with no apparent cause may indicate poisoning by a toxic plant. If plant poisoning is suspected, the responsible plant(s) must be identified, which is sometimes a difficult task. Symptoms may be similar across multiple poisonous plants, all symptoms may not manifest, and some symptoms may be atypical. Sometimes poisoning is even caused by a plant not commonly recognized as toxic. Examine the rangeland or pasture for poisonous plant species.
Halogeton (Halogeton glomeratus) has red stems and fleshy leaves. It has caused hundreds of livestock deaths in a single day at one location in various western states. Livestock should not be allowed to become hungry or thirsty while grazing in areas infested with halogeton, as they will graze indiscriminately. Proper rangeland management is the best way to minimize livestock losses.
The maintenance of regular, detailed livestock management records can be a useful tool when diagnosing plant poisoning for an animal displaying symptoms. For example, information about the date animals entered a pasture, where they moved from, their general health prior to symptom onset, and utilization of suspected plants can all be important. If the animal is alive, careful observations and notes about its behavior should be made. If the animal has recently died, an inspection in the digestive tract (or a complete necropsy) for identifiable plant parts is recommended, along with an examination for abnormal-appearing organs. Contact a veterinarian or other qualified individual for help making a diagnosis. Whether or not an animal is treated for plant poisoning may be decided by behavioral observations, noted above, and by correct identification of the suspected poisonous plant. Ultimately, correct identification of the plant is essential for any long-term proactive corrective action and should be considered an important starting point if problems occur.
When the presumed causal plant is identified, it should be collected for verification by someone with plant identification expertise. Collect the entire plant or, if too large, representative parts of the plant (roots, stems, leaves, flowers, fruits, and unique attributes). Record information regarding date, location, habitat, plant size, and plant growth characteristics. Photographs of the plant and its habitat are also useful. Soon after collection, press the specimen between two pieces of newspaper or cardboard to air dry. Alternatively, place the plant in a bag in a refrigerator for short term storage if needed. If mailing the specimen for verification, place the pressed sample or bag in a padded envelope or box. Use caution when handling specimens as some plants are toxic to humans too!
Submit samples to one of the following:• Local Extension or USDA-NRCS offices • Montana State University Schutter
Diagnostic Laboratory (http://diagnostics.montana.edu/)
• University of Wyoming Herbarium (http://rmh.uwyo.edu/data/search.php)
• USDA-ARS Poisonous Plant Research Laboratory (https://www.ars.usda.gov/pacific-west-area/logan-ut/poisonous-plant-research/)
Indirect losses include the following management costs:• Building and maintaining fences• Increased feed requirements• Increased medical treatments• Altered grazing programs• Decreased forage availability• Decreased land values• Increased stress on livestock managers
Photo: M. Lavin, MSU
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Factors Influencing Plant Toxicity to LivestockPlant-relatedDoseThe dose (i.e. amount consumed) needed for a plant to cause undesirable effects to livestock depends on factors like the amount and concentration of a toxin and how rapidly it is consumed. In plants, the dose is influenced by growing season, growth stage, palatability, and growing conditions. Some plants are lethal after one exposure or a short duration of time, other plants may require ingestion of large amounts before affecting livestock, and other plants cause poisoning weeks or months after ingestion. Acute poisoning occurs when animals are exposed to a toxic dose on one occasion or for a short time and symptoms are relatively instantaneous. For example, cattle or sheep consuming small amounts of poison hemlock will exhibit symptoms of poisoning within an hour. Chronic poisoning is long-term, repeated, or continuous exposure to a toxin. The toxins accumulate in the animal’s body over time, symptoms are delayed, and damage is usually irreversible. For example, cows consuming lupine during their early gestation period may show no evidence of poisoning until they give birth to calves with cleft palates and skeletal defects (i.e. crooked calf syndrome).
Information on what constitutes a toxic dose is only available for commonly problematic species in Montana and Wyoming (Table 2), and, in many cases, is based on limited scientific research. The toxic dose is dependent on plant-related factors discussed below, as well as animal-related factors such as animal health, species, and age.
Season and Plant Growth StagePoisonous plants vary in their toxicities and palatability with season and growth stage. Rangeland and pasture should be examined for the kinds, quantities, and distribution of poisonous plants before livestock are allowed to graze. Some areas should be avoided during the most dangerous season if dense stands of poisonous plants grow there. For example, some plants are most palatable during their early growth stages, making spring the most dangerous period for poisoning.
Chokecherry (Prunus virginiana) leaves have finely toothed margins and a short, pointed tip. The toxic substance in chokecherry, hydrogen cyanide, is found principally in the leaves. Leaves become less toxic as the growing season progresses.
Poison hemlock (Conium maculatum) is 2 to 20 feet tall with white flowers, finely dissected leaves, and purple spots on the stem. Livestock poisoning is most common in the early spring when tender, succulent, highly toxic new leaves begin growth.
Lupines (Lupinus spp.) have palmately compound leaves which radiate from a central point. Lupine poisoning can be reduced by keeping hungry animals away from lupine in early growth stages and in late summer when the plant contains seeds that are very toxic.
Photo: A. Oomen, bugwood.orgPhoto: USDA-NRCS Photo: T. Nelson, USDA-NRCS
Photo: M. Lavin, MSU
Some poisonous plants are most toxic when they are immature, others when mature, and still others are equally toxic at all growth stages (see Tables 1 and 2). Toxic substances are often concentrated in certain plant tissues, and negative impacts may only be apparent
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Arrowgrass (Triglochin maritima) has fleshy, dark-green, grass-like leaves and a slender flower stalk. Arrowgrass plants quickly become toxic when stressed or damaged from drought, frost, or cutting. Foliage that re-grows following harvest is also toxic.
Shadscale saltbush (Atriplex confertifolia) has grayish bark, alternate leaves, and fruits with four conspicuous wings. It accumulates high levels of selenium when growing in selenium-rich soils and can cause chronic selenium poisoning when consumed by livestock .
Photo: K. Clause, NRCS
Photo: M. Lavin, MSU
Component of HayPlant toxicity may increase, decrease, or remain static when foliage dries. This factor and the plant’s stage of development when harvested, is important in determining toxicity of hay containing poisonous plants. When poisonous plants are mixed with non-poisonous plants and fed together in hay, livestock are unable to discriminate between them as readily as when grazing in a field and are consequently more vulnerable to poisoning. Areas containing substantial amounts of poisonous plants should not be hayed, and hay containing poisonous plants should not be fed to livestock without consulting with the local Extension agent, NRCS employee, or another qualified person.
Growing ConditionsPlants growing during stressful conditions (e.g. drought, freezing) commonly have increased toxicity levels. For example, arrowgrass grown with adequate moisture does not cause hydrogen cyanide poisoning, but when growth is stressed or stunted from inadequate moisture, arrowgrass quickly becomes toxic. This
problem can be exacerbated by a lack of palatable forage during drought which can cause livestock to eat any plant available, even species with toxic properties.
The concentration of different elements in soil can influence several species of poisonous plants. For example, certain species of saltbush and milkvetch growing in soils high in selenium accumulate toxic quantities of this element, whereas the same saltbush species may provide good forage on soils low in selenium.
When certain species grow in the same vicinity and are grazed in combination, toxic effects can vary. For example, sheep feeding on horsebrush just following or in conjunction with black sage and then exposed to bright sunlight may develop a characteristic swelling of the head called bighead (i.e. photosensitization). Sheep grazing horsebrush alone may experience toxic impacts without developing bighead.
PalatabilityPalatability is important because it determines livestock utilization of poisonous plants. Many poisonous plants are not very palatable, so animals will usually select more palatable, non-poisonous species. If an area does not offer enough palatable non-toxic forage, however, animals are more likely to consume toxic quantities of poisonous plants. In addition, palatability is highly variable and can change over the growing season or in response to recent climatic events (e.g. frost) or vegetation management. For example, many species, including poisonous plants, are more palatable for a few weeks following herbicide or fertilizer application.
when consumed at the time of year when these tissues are available. For example, plants with toxins most concentrated in seeds should not be grazed during seed development and ripening.
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Ponderosa pine (Pinus ponderosa) can cause abortions during the last trimester of pregnancy if cattle graze approximately 5 to 6 pounds of needles. The needles are generally grazed during the winter when forage is lacking or snow-covered. Prevent poisoning by limiting access to ponderosa pine during the last trimester.
Milkvetch species (Astragalus spp.) have pea-shaped flowers and grow in a variety of native habitats. Many milkvetch species can cause acute or chronic poisoning of livestock. Cattle will readily eat some toxic milkvetch species even when other forage is available. To reduce livestock losses, prevent animals from grazing these plants for extended periods, feed protein supplements, and avoid stressing cattle that have grazed toxic milkvetch species.
Horsetail species (Equisetum spp.) have hollow, jointed stems, and grow in moist to wet meadows and pastures. Horsetail can have whorls of branches at the joints (left photo) or a single, unbranched stem (right photo). It is often cut and incorporated in hay where it retains toxic properties when dry. Cattle or horses fed hay containing more than 20% horsetail can experience gastrointestinal and nervous system poisoning effects.
Photo: T. Nelson, USDA-NRCS Photo: USDA-NRCS
Photo: USDA-NRCS
Photo: M. Lavin, MSU Photo: M. Lavin, MSU
Animal Response to ToxinSome toxins quickly change to harmless substances upon ingestion or are rapidly eliminated after entering the body and are therefore usually of little danger to an animal. Alternatively, toxins rapidly absorbed into the animal’s circulatory system following ingestion are very dangerous.
Animal HealthAnimals within the same livestock class or breed may vary in their susceptibility to plant toxicity. For example, in a study that dosed Angus steers with larkspur and then imposed the steers to stressful conditions, 40% were considered resistant and the remaining 60% were too sensitive to even impose the stress without risk of death. Livestock in poor condition or subjected to adverse conditions or stress (e.g. temperature, exertion, etc.) are usually more susceptible to poisoning than non-stressed animals in good condition. Hungry animals may ingest higher quantities of a poisonous plant, while satiated animals are more selective and tend to consume lower doses of a toxic plant. In general, an animal will consume less poisonous plant tissue when it can graze selectively.
Animal-related Animal Species, Gender, Size, and AgeSome poisonous plants have a more negative effect on one specific class of livestock, while other plants are equally toxic across all classes. Different classes of livestock preferentially graze certain types of plants. For example, cows and horses prefer grasses, while sheep prefer forbs and shrubs. Rangeland and pasture should be inspected for the kinds and quantities of poisonous plants before grazing. This information can be used to decide what class of livestock should be grazed. Livestock losses may be prevented by grazing those animals that will not be harmed by the poisonous plants present. Also, skin color can determine susceptibility of animals to photosensitivity after eating certain poisonous plants. For example, light- to white-skinned individuals (Hereford cows, white-faced horses) are more photosensitive and will suffer sunburned faces or udders.
Toxicity to some poisonous plants is gender-specific, particularly as it pertains to animal reproduction. For
example, ingestion of ponderosa pine needles by male cattle appears harmless while it may cause abortions in pregnant females. Additionally, the size of animals within a class of livestock may be proportional to the quantity of toxin required to cause poisoning. As animal size increases, the amount of poisonous plant needed to be consumed to cause toxicity symptoms also increases. Younger animals are usually more susceptible to poisoning than older animals. It has been shown that yearling steers may be more susceptible to larkspur poisoning than two-year-old steers.
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Many invasive plants have poisonous properties including houndstongue, blueweed, field bindweed, hoary alyssum and more (see Table 3). Houndstongue (Cynoglossum officinale) is an invasive biennial forb that is sometimes harvested in hay where it can cause poisoning. Animals may graze pasture containing poisonous invasive plants without ill effects if ample good forage is available.
Conditions Leading to Livestock Poisoning and Management to Reduce ImpactsThe most effective way to prevent livestock loss from poisonous plants is to properly manage rangeland, pasture, forest, and livestock. Develop a grazing plan that improves or maintains rangeland or pasture condition and prevents poisoning. Plans should consider poisonous plants in the area, allowing animals to avoid them or graze them at the most appropriate time. Poisoning typically occurs when livestock are enticed by hunger or other stressful conditions, although there are exceptions where animals may show an unexplained preference for a poisonous plant. Livestock managers should know what poisonous plants are present and how to prevent animal intake. Hundreds of plants are poisonous to livestock at certain doses. Many are always toxic, whereas others are toxic only under certain conditions. In some situations, a poisonous plant may even form an important part of livestock diets without negative effects on the animals (e.g. greasewood).
Grazing Rangeland and Pasture that Are in Poor ConditionA common condition under which plant poisoning occurs is grazing rangeland and pasture that are in poor condition. Generally, as vegetation is overgrazed,
palatable species are reduced in abundance and less palatable species, including invasive and/or poisonous plants, increase. As pasture condition continues to decline, animals have to consume increasing quantities of less palatable and possibly poisonous plants to meet their nutritional requirements. The association between scarcity of forage and increased consumption of poisonous plants cannot be ignored when trying to mitigate toxicity issues. Livestock managers should use good grazing management, graze during the correct season, and use appropriate animal stocking rates.
Hungry Animals on Infested Rangeland, Pasture or Cover CropHungry animals graze less selectively than satiated animals and tend to eat whatever is within close proximity. Hungry animals should never be exposed to areas with large concentrated populations of poisonous plants. Poisoning often occurs when animals consume too much or eat too rapidly, behavior typical of hungry animals.
Early Season Grazing on RangelandWhen native rangeland or pastures are grazed too early in the growing season, the earliest growing
Photo: M. Lavin, MSUPhoto: USDA-NRCS
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species must carry the grazing load. If palatable, non-poisonous plants are unavailable, livestock will eat whatever is available, including poisonous plants. Several poisonous plants (e.g. low larkspur, lupine, deathcamas) are among the first to emerge in the spring and are in their most succulent stages. Livestock should not be released onto rangeland or pasture until adequate desirable forage is available to support grazing.
Livestock Familiarity with the AreaAnimals new to an area, especially previously confined animals, tend to graze less selectively and may consume a greater diversity of plants (including poisonous plants) than animals which are familiar with the area. In other words, they are naïve to toxic plants in a new pasture. Where livestock are grazed in unfamiliar areas, handlers should watch animals carefully. Be especially careful when grazing newly acquired livestock that are in unfamiliar rangeland or pasture. Once an animal becomes familiar with an area and its toxic plants, it may be safe to graze the pasture. For example, on rangelands where locoweed is abundant, it is safe to graze only those animals which are acquainted with locoweed but do not seek it out for consumption.
Improper Herding, Driving and BeddingCrowded animals need time to scatter across an area large enough to allow selective grazing. When animals are crowded, they may be forced to eat whatever vegetation is available. Livestock managers can minimize poisonous plant consumption by using open or loose herding methods with slow movement.
Animals often become nervous when they are driven or trailed. When being moved, animals are also unable to quickly satisfy their hunger like they would under normal pasture conditions, and they become less selective in their plant consumption. Animals that are both hungry and driven quickly are even more susceptible to poisonous plants. To minimize losses, animals should be satiated and driven slowly through areas with poisonous plants.
Livestock prefer to graze late in the evening and in the morning after leaving their bedding grounds. They are less selective in their grazing habits during these times and are more likely to consume toxic quantities of poisonous plants. The risk of plant poisoning increases when animals are bedded down in the same area for several nights.
High-use areas are subject to overgrazing of palatable plants, resulting in an increase of unpalatable plants, many of which are poisonous. Livestock managers can
Meadow deathcamas (Zigadenus venenosus), a perennial with long linear leaves, is one of the first plants to begin growth in early spring. Without enough other forage, deathcamas species may be heavily grazed and will cause livestock losses.
Greasewood (Sarcobatus vermiculatus) is adapted to saline soil where it uptakes and accumulates soluble sodium and potassium oxalates in the fleshy leaves. It can be safely eaten by livestock in moderate amounts with other forage. However, poisonings can occur when livestock eat large amounts of greasewood leaves or buds in a short period of time.
Locoweed species (Oxytropis spp.) are poisonous at all stages of growth throughout the year including when dried. Livestock that have never grazed locoweed will usually avoid it; however, once consumed, an animal can become habituated to grazing locoweed. Livestock owners can reduce losses by removing locoweed-eating animals from the herd.
Photo: USDA-NRCS Photo: M. Lavin, MSU Photo: USDA-NRCS
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reduce losses by selecting new trails and bedding grounds when possible.
Inadequate Nutrient SupplyAnimals with nutrient deficiencies often seek plants that contain high levels of the nutrient that the animal is lacking. For example, salt-deficient animals may seek out and excessively consume salt-accumulating plants like greasewood. To minimize losses, place salt and phosphorous supplements in several locations in the pasture and throughout the entire period of use of the pasture. Salt and phosphorous supplements can also be used to improve livestock distribution and lure them away from areas supporting poisonous plants. Do not place salt and other supplements in an area where poisonous plants are growing.
Water Quantity and QualityAnimals tend to graze indiscriminately when they have been without water for more than two days and are finally given the opportunity to drink. Therefore, do not place or develop water in areas where toxic plants are present. Always provide animals with an adequate supply of water.
Water quality is an important aspect of livestock management and animal performance. If water sources become contaminated with fertilizers or manure, blue-green algae can proliferate and lead to poisoning. Pesticide drift may also contaminate water sources and endanger livestock. Additionally, elevated levels of nitrates, metals (e.g. copper, lead, zinc), and other elements (e.g. selenium, arsenic, boron) in soil can lead to unsafe levels in surface and groundwater. Have water sources tested annually, determine if results are within recommended water quality standards, and take steps to determine the source of any problem.
Environmental ConditionsLate spring and early fall snowstorms may cover shorter, more desirable species, leaving taller statured poisonous plants like tall larkspur, deathcamas, and lupine as the only vegetation available to livestock. Poisoning potential may be compounded in the fall if fruiting (podded) plants extend above the snow, and those fruits are highly toxic. To minimize losses, either move or feed supplements to livestock subjected to these conditions.
Following heavy rain, some poisonous plants become more palatable or toxic because the rain stimulates new plant growth. This is especially problematic if other vegetation becomes matted and entangled, making it
Many plant species with poisonous properties, including tall larkspur, water and poison hemlock, iris, and buttercup, grow near livestock water sources such as seeps, springs, or wet meadows (see Table 3). Livestock should be moved from areas where poisonous plants surround water developments, especially during the species’ toxic window. Tall larkspur (Delphinium occidentale) poses a risk of poisoning during flower and early seedpod growth stages.
difficult for livestock to graze as discriminately as under drier conditions. When this situation arises, consider moving livestock to other areas or feeding supplements to reduce consumption of poisonous plants.
Drought can lead to early maturation of many palatable plants. In contrast, several poisonous plants remain green during drought (e.g. deep-rooted lupines or locoweed; evergreen yew or laurel). As a result, these poisonous plants may become more attractive to livestock, receive more use, and increase the risk of poisoning. The adverse effects of drought are worsened
Photo: T. Nelson, USDA-NRCS
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on overgrazed rangeland and pasture where more palatable non-poisonous plants were already stressed. These areas are also susceptible to an increase of poisonous plants when wet years follow drought.
Well-managed rangeland and pasture leaves some forage to carry-over for use during drought. During extended droughts, livestock numbers may need to be reduced or supplemental feeding initiated.
Cultural PracticesCultural practices, such as spraying herbicides or spreading fertilizer, may increase the palatability of poisonous plants for a short time after application. Certain herbicides (e.g. glyphosate, 2,4-D) will increase the plant sugar content and sweetness, making it more palatable to livestock. Salt-based herbicides can also make poisonous plants more attractive. All animals should be kept off rangeland or pasture supporting poisonous plants for at least two weeks following applications of herbicides or fertilizers, and always follow grazing restrictions on the product label.
Grazing System Grazing systems vary by timing, frequency, duration, and intensity of livestock use and can be manipulated to help manage poisonous plants. Timing refers to the season grazing occurs, and frequency is how often a pasture is grazed. Duration is how long a pasture is grazed. Intensity involves stocking density (i.e.
number of animals per acre) and is the cumulative effect grazing animals have on forage during a time period. For example, an intensive grazing management system does not necessarily lead to high grazing intensity (utilization) but it does require management that optimizes stocking density and duration to achieve utilization objectives.
Timing can be manipulated to avoid grazing when plants are most toxic. Intensity can be manipulated in some situations to alter the selectivity or amount of a plant that is consumed by each animal. For example, high intensity grazing systems (i.e. a higher density of animals for a shorter amount of time in a pasture) result in lower forage selectivity. While this could lead to increased consumption of poisonous plants, and must be carefully managed, this approach may also limit the amount of exposure any single animal has to a poisonous plant, thus limiting dose. High intensity grazing systems are most effective when there is adequate non-toxic forage and fewer poisonous plants.
It is important to note that pastures that are grazed with high frequency and long duration can expose livestock to higher risk of consuming a toxic dosage of a poisonous plant as the livestock exhaust preferred forages. However, when livestock are moved more frequently to new pastures with adequate high-quality forage, the risk of consuming poisonous plants decreases.
Because some poisonous plants are more palatable or available at certain times of the year, seasonal grazing can be a consideration for avoiding poisonous plants at toxic doses. In the example of tall larkspur, infested pastures could be grazed early or late, ultimately avoiding the toxic window (or the time when toxicity is greatest) that occurs for about five weeks at the start of the flowering stage and ends in the pod stage. However, a grazing system
that relies on grazing a pasture every year during the same season can also result in decreases in palatable, non-poisonous plants and increases in less palatable and poisonous plants, particularly in a rangeland setting.
Locoweed species (Oxytropis sericea pictured here) grow in a variety of habitats, have pea-shaped flowers that can be white, yellow, blue or purple, and can remain green when other vegetation is dormant. Livestock owners can reduce locoweed losses by keeping animals off pastures until good forage is available.
Photo: M. Lavin, MSU
Photo: USDA-NRCS
- 13 -
Larkspur (Delphinium spp.) is highly palatable to cattle, and losses occur when cattle graze larkspur-infested areas when it is abundant or growing in large patches. Low larkspur (Delphinium bicolor), with its characteristic blue-purple spurred flowers, completes its lifecycle in the early spring. Livestock losses can be prevented by deferring grazing until plants lose their flowers and pods when it rapidly senesces.
Cover crops usually palatable and nutritious to livestock can pose a poisoning risk during periods of environmental stress or as a result of crop management, harvest, or storage.
Multi-species GrazingThe use of different livestock species in a multi-species grazing approach is a strategy to mitigate toxicity. For example, sheep can tolerate larkspur at doses four times greater than cattle, so larkspur poisoning of sheep is rare. A strategy of grazing sheep prior to grazing cattle could reduce larkspur abundance and decrease the risk of cattle consuming larkspur later.
Crop and Cover Crop GrazingCrop and cover crop management, harvesting, and storage may influence the risk of livestock poisoning. Most toxicity risks with grazing cover crops are associated with nitrates in small grains, hydrogen cyanide (HCN, also known as prussic acid) from sorghum and sorghum-sudangrass, and mycotoxins such as fusarium and ergot from various grass species. In general, monocultures or low diversity cover crops on highly fertilized land pose the highest risk of accumulating nitrates and affecting livestock if grazing is too heavy. Similarly, appreciable quantities of HCN can accumulate in new growth of cover crop species following clipping, drought, frost, hail damage, or grazing. Risks of poisoning from crops can be reduced by waiting to graze until plants have reached the proper height, maintaining a six-inch stubble height, grazing during daylight only, and waiting to graze until one
week after a killing frost. In addition, when selecting species for a cover crop mix that will be grazed, plant a diverse cover crop mix, use certified seed, and select varieties low in HCN to minimize the risk of poisoning. A cover crop sample should be tested for nitrates prior to grazing.
Care for Impacted AnimalsPreventing livestock poisoning is usually easier than curing a poisoned animal. There is often no antidote available for a plant toxin, and rangeland or pasture conditions may make treatment difficult. When a poisoned animal is found alive, if possible and without causing stress, it should be placed in a cool, shaded area with proper food and water. However, care should be taken when moving animals. Moving animals impacted from consuming a poisonous plant (e.g. larkspur) can exacerbate the problem. Contact a veterinarian as soon as possible to diagnose and treat the animal.
Help with poisonous plant problems may also be obtained from local veterinarians:• Wyoming State Veterinary Laboratory
(http://www.uwyo.edu/wyovet/)
• Montana Veterinary Diagnostic Laboratory (http://liv.mt.gov/Diagnostic-Lab)
Photo: M. Lavin, MSU
Photo: M. Lavin, MSU
Photo: M. Henning, USDA-NRCS
- 14 -
Control of Poisonous Plants
Leafy spurge (Euphorbia esula) can form dense infestations that can cause skin and gastrointestinal issues for cattle but can be managed by sheep grazing. Control methods for poisonous plants will depend on the species, site condition, and size of the infestation.
Poisonous Substances and Other Forage Problems
invasive properties, and some are listed on county or state noxious weed lists (e.g. leafy spurge, common tansy; Table 3). Be aware that some herbicides (e.g. 2,4-D) may increase palatability of the toxic plants. Also, herbicides may impact desirable non-target plants and reduce diversity and quality of the vegetation. If chemical control is necessary, obtain management information from your local Extension, Montana Weed District, or Wyoming Weed and Pest office.
Many poisonous plants in Montana and Wyoming are native species and a natural part of plant communities. Most native poisonous plants do not naturally dominate the plant communities where they occur, or their presence is the result of disturbance. Generally, control of native poisonous plant species is not needed. Instead, good grazing management strategies should be implemented to allow desired species to outcompete poisonous ones. Proper stocking rates and the initiation of a good grazing system may reduce the abundance of poisonous species through competition with desired non-poisonous species. In addition, several poisonous native plant species have beneficial forage attributes which offset their poisonous properties. For example, greasewood is poisonous when eaten nearly exclusively but is valuable forage when consumed with a moderate amount of other desirable forage plants. If small scale management of native poisonous plants is necessary, mechanical (mowing, digging), cultural (exclusion fence, proper land management), biological (selective grazing, insects), herbicides, and/or revegetation can be used.
In contrast, many introduced (i.e. non-native) plant species with toxic properties can form dense infestations. Many of these species have weedy or
Poisonous plants contain at least one of the following:
• Substances that are directly poisonous to livestock. Alkaloids contained in certain lupine species and oxalates contained in halogeton are common examples.
• Substances that are themselves harmless, but become toxic as they decompose slightly before or upon ingestion by the animal. Chokecherry leaves, for example, contain the glycosides amygdalin and prunnasin which, upon hydrolysis (mixing with rumen microbes), forms highly toxic hydrogen cyanide (also known as prussic acid or hydrocyanic acid).
• Substances absorbed from soil and accumulated to toxic levels by the plant. For example, several milkvetch species can accumulate selenium.
• Substances which make parts of the affected animal hypersensitive. An example is the pigment hypericin (contained in St. Johnswort) that causes white-skinned animals to be hypersensitive to sunlight.
• Miscellaneous substances such as toxic elements or metals (fluorine, arsenic, etc.) that can accumulate on or in plants found near industrial developments, toxic products formed by fungi in moldy hay or silage, contact irritants, and poor water quality caused by blue-green algae blooms.
Photo: USDA-NRCS
- 15 -
in a progressive decrease in electrical conductivity through the heart and blocks cardiac activity. While low doses of cardiac glycosides can be beneficial by slowing heart rate, increasing the contraction force and increasing cardiac output, animals consuming toxic doses develop heart and digestive disturbances leading to death. Additional signs of poisoning include rapid breathing, cold extremities, and a rapid, weak, irregular pulse caused by cardiac arrhythmias and heart block. Death typically occurs within 24 hours of the onset of symptoms.
Plants containing cardiac glycosides: Milkweeds and dogbanes can cause cardiac glycoside poisoning. However, cases of cardiac glycoside problems are rare, especially for dogbane.
Nightshade species (Solanum nigrum pictured here) have tomato-like, star-shaped flowers with five petals. They are not usually palatable to livestock but cause issues when harvested with hay or grain crops then fed to livestock. Losses can be minimized through pasture management and weed control.
Milkweed species (Asclepias speciosa pictured here) can have broad or linear leaves arranged alternately or in whorls. It is most dangerous when actively growing, but toxicity decreases with drying. Livestock tend to consume milkweed when other forage is limited, after a frost, or when it is incorporated in hay.
Principal ToxinsThe most common toxic substances in Montana and Wyoming plants are described below. Less common toxic substances are described in the Glossary.
Alkaloids Alkaloids are generally present in plants as an organic acid. There are over 40 different types of alkaloids that cause poisoning, and some plants may contain more than one. Alkaloids are always present and well-distributed throughout plant tissues. The relative toxicity and concentration of individual alkaloids varies among plant species and populations. Common human-consumed alkaloids include caffeine and nicotine. Types of toxic alkaloids include steroidal, pyrrolizidine, indolizidine, piperidine, diterpenoid, quinolizidine, and tropane.
Symptoms: Alkaloids ingested by livestock cause a strong physiological reaction. Alkaloids, such as those found in larkspur, induce muscular paralysis. Swainsonine, associated with locoweed, causes significant poisoning issues referred to as “locoism.” Signs of locoism may include depression, circling, staggering, reproductive failure, heart failure, and weight loss. In addition, a compromised immune system stemming from locoism may lead to other ailments such as foot rot, pneumonia, warts, and other infections. Alkaloid symptoms of the extremities (i.e. feet and ears) include vasoconstriction and reduced blood flow. Teratogenic species, including locoweed, groundsel, false hellebore, lupines, and poison hemlock, harm the developing fetus if plants are consumed at certain stages of gestation.
Plants containing alkaloids include but are not limited to: tall and low larkspur, monkshood, poison hemlock, deathcamas, nightshades, black henbane, locoweed, lupines, tansy ragwort, houndstongue, milkvetch, yew, false hellebore, and others.
Cardiac Glycosides Cardiac glycosides have direct effects on cardiac func-tion. Cardiac glycosides are present throughout the plant, especially the leaves, and retain reduced toxic-ity when dried. Small quantities of ingested plants can cause symptoms.
Symptoms: Cardiac glycosides directly impact the gastrointestinal tract causing hemorrhagic enteritis, abdominal pain, and diarrhea. Cardiac glycosides also inhibit the cellular membrane sodium-potassium pump which results
Photo: USDA-NRCS
Photo: USDA-NRCS
- 16 -
Cyanogenic Glycosides Cyanogenic glycosides are indirectly toxic in that they hydrolyze to produce hydrogen cyanide (HCN, also known as prussic acid) in the presence of certain enzymes and when acted upon by microorganisms in the plant or rumen. Hydrogen cyanide is a highly toxic, rapidly acting poison that inhibits oxygen utilization by cells. Some plants naturally have high levels of cyanogenic glycosides, especially in early growth stages, rapidly growing plant parts, and seeds. In other plants, the level of cyanogenic glycosides is influenced by climatic conditions, soil factors, and other factors that slow growth. Enzymatic conversion to HCN is enhanced when plant cells are damaged from drought, wilting, freezing, or crushing, or when stressed from low soil moisture, high nitrogen, low phosphorous, or herbicide applications. Avoid grazing plants high in cyanogenic glycosides while these conditions exist and wait at least a week after a severe drought or frost before grazing. Hydrogen cyanide deteriorates with time; therefore, dried hay is safe to consume.
Symptoms: Nitrate Nitrate poisoning is caused by excessive consumption of nitrate (NO3) or nitrite (NO2). Under normal conditions, nitrates are converted during digestion to nitrite; the nitrite then becomes ammonia which in turn is converted to protein. When high levels of nitrates are consumed, nitrite will accumulate in the rumen. Since nitrite is up to ten times more toxic than nitrate, poisoning can occur. Nitrate poisoning is a problem for ruminants (cattle, sheep) but is unlikely in monogastric animals (horses) because monogastric animals can’t readily convert nitrate to nitrite in their digestive systems.
Nitrates are most concentrated in plant stems and stalks, and to a lesser degree leaves; they do not accumulate in flowers or seeds. Nitrate levels are highest in young plants and decrease with maturity. Nitrates decrease only slightly with drying, so feeding nitrate-rich hay can be a problem.
Symptoms: Nitrite is absorbed into the bloodstream and converts hemoglobin to methemoglobin which interferes with the ability to carry oxygen from the lungs to the tissues. Signs of nitrate poisoning are related to the lack of oxygen in blood including: blue to chocolate brown mucous membranes
Serviceberry (Amelanchier alnifolia) grows up to 13 feet tall and produces clusters of white flowers in early spring. The upper ½ to ¾ edge of the leaf is toothed which distinguishes it from chokecherry whose leaves are toothed along the entire edge. Like chokecherry, serviceberry produces hydrogen cyanide and foliage is especially poisonous in the early flowering stage.
Hydrogen cyanide rapidly inactivates cellular respiration leading to a characteristic cherry-red venous blood from the failure of oxygen releasing at the tissues. The heart and brain are affected by a lack of oxygen, causing death to occur within one to two hours or several minutes in acute cases. Signs of poisoning prior to death include difficulty breathing, frothing at the mouth, irregular pulse, dilated pupils, staggering, muscle tremors, bright red mucous membranes, and convulsions. Chronic ingestion of low levels of cyanogenic glycosides can cause various neuropathies, musculoskeletal deformities, and goiter. Cattle and sheep (ruminants) are more susceptible to HCN poisoning than horses (monogastrics). Fetuses are also extremely sensitive to HCN poisoning.
Plants containing cyanogenic glycosides: Hydrogen cyanide poisoning is most commonly associated with Johnsongrass, sudangrass, sor-ghum-sudan grass, chokecherry, serviceberry, and arrowgrass.
Photo: T. Nelson, USDA-NRCS
Photo: T. Nelson, USDA-NRCS
- 17 -
Russian thistle (Salsola tragus), a highly branched herbaceous weed with spine-tipped leaves, can accumulate nitrate. Many plants, including crop and weed species, can accumulate nitrate. Plants containing between 0.5% to 1.5% nitrates can have sublethal effects on livestock, while plants with more than 1.5% nitrates may be lethal to livestock.
Kochia (Bassia scoparia) has green or reddish stems, linear leaves, and is often covered with silver or rusty hairs. Kochia and other members of the goosefoot family (Chenopodiaceae) have been associated with oxalate and nitrate poisoning, although occurrences are uncommon.
or blood, difficulty breathing, rapid pulse, salivation, staggering, coma, and death. Sublethal or chronic nitrate poisoning can cause abortion during any stage of gestation due to lack of oxygen.
Plants containing nitrates: Rangeland and pasture plants known to accumulate nitrates include redroot pigweed, lambsquarters, kochia, curly dock, Russian thistle, nightshades, and Johnsongrass. Grazed crop or cover crop species known to accumulate nitrates include barley, oats, millet, rye, sorghum-sudangrass, wheat, corn, alfalfa, sugar beet, rape, radish, and turnip.
Contact your local Extension or Department of Agriculture office for assistance testing forage for nitrate content. In Montana, MSU Extension offers an in-office test to rapidly assess the presence of high forage nitrates. In Wyoming, the Department of Agriculture offers feed and forage analyses for nutrients and toxic constituents.
Oxalates Oxalates cause problems when livestock are not accustomed to grazing oxalate-containing plants. Animals can tolerate grazing oxalate-containing plants if they have other plants in their diet to dilute oxalate in the rumen. For example, cattle can graze sites dominated by greasewood if there is ample grass. However, if there is very little grass and greasewood leaves have dropped to the ground, cattle intake of greasewood may increase along with the risk of oxalate poisoning. Also, gradually introducing ruminants to oxalate-containing plants can increase rumen microflora that degrade oxalate and minimize impacts. Supplementing livestock’s diet with dicalcium phosphate before and during high-risk oxalate exposure, can effectively reduce losses.
Symptoms: Oxalates occurs in two forms: insoluble calcium oxalate and soluble oxalates. Insoluble calcium oxalate, a needle-like crystal, causes severe damage to kidney tubules. This chronic form of oxalate poisoning leads to renal failure and death. Soluble oxalates rapidly combine with and decrease serum calcium and magnesium, thus impairing normal cell membrane function. This acute oxalate poisoning causes muscle tremors, weakness, collapse, and death.
Plants containing oxalates include halogeton, redroot pigweed, lambsquarter, kochia, sorrel, curly dock, greasewood, and purslane.
Photo: M. Lavin, MSU
Photo: M. Lavin, MSU
Photo: M. Lavin, MSU
- 18 -
Saponins Saponins are naturally occurring glycosides in plants that have soap-like compounds. Saponins increase the permeability of membranes and may cause hemolysis of red blood-cells, thus releasing hemoglobin.
Symptoms: Plants containing saponins may act as a diuretic causing diarrhea. Other symptoms include biliary obstruction, bloat in ruminants, photosensitivity, salivation, acute hepatopathy, and death. Some saponin containing plants (e.g. oats) are beneficial when consumed, increasing and accelerating the ability to absorb compounds such as calcium and silicon that assist in digestion.
Plants containing saponins include snakeweed, puncturevine, kochia, and bouncingbet.
Selenium Selenium is an essential nutrient for animals, but it accumulates in certain plants to levels that are toxic to livestock when those plants are growing in selenium-rich soils. For example, some species of saltbush provide good forage on soils with low selenium levels but are poisonous when growing on soil high in selenium. Selenium-rich soils are derived from cretaceous shales and glacial deposits and are generally found in semi-arid areas. Plant uptake is variable and depends on the chemical form of selenium, soil pH, temperature, moisture, plant species, and stage of plant growth.
Symptoms: Selenium intoxication can occur as acute or chronic poisoning. Signs of acute selenium poisoning, occurring when animals ingest more than 50 parts per million (ppm), include abnormal posture, unsteady gait, abdominal pain, increased pulse and respiration rate, and sudden death. Chronic selenium poisoning is more common, with symptoms including rough coat (bob-tail, roached-mane), hair loss, hoof lesions, lameness, defective hoof growth, and reduction in fertility.
Plants containing selenium: Plants with more than 5 ppm selenium are potentially toxic. Primary selenium accumulator or indicator plants may accumulate up to several thousand ppm selenium. Obligate accumulator species, including milkvetch and princesplume, can cause acute poisoning but are rarely consumed due to poor palatability. Secondary selenium accumulator plants may contain up to several hundred ppm selenium, but lesser amounts are much more common. This group includes aster species, milkvetch, saltbush, Indian paintbrush, curlycup gumweed, and snakeweed. The low-accumulator group, including alfalfa, corn, and grains, rarely accumulate more than 50 ppm selenium and usually only 5 to 12 ppm. However, it is the low-accumulator plants that cause the most toxicity problems because they are commonly grazed by livestock and can lead to chronic selenium poisoning.
Milkvetch species (Astragalus spp.) have pinnately compound leaves and pea-shaped flowers and are primary selenium accumulators. To prevent animals from eating excessive amounts of selenium, identify areas of high selenium soil and develop a grazing or forage-production plan.
Photo: USDA-NRCS
Photo: USDA-NRCS
- 19 -
Alfalfa (Medicago sativa) is an important forage species with trifoliate leaves and purple or blue, occasionally yellow, flowers. Risk of poisoning from alfalfa and other forage legumes depends on the amount and rate of consumption, composition of the animal’s diet, the plant’s accumulation of toxic chemicals (e.g. selenium, nitrate), and how the crop was managed, harvested, or stored.
Some plant species, although not poisonous, can cause injury to animals resulting in discomfort, inflammation, or poor condition. Mechanical injuries can be caused by native or non-native species with long awns such as foxtail barley (Hordeum jubatum), needle-and-thread, or cheatgrass.
Other Forage Problems and DisordersBloat Bloat is caused by the entrapment of fermentation gases in the rumen. Bloat usually occurs when livestock consume lush legumes such as alfalfa or white clover. Soluble proteins in forages and other small particles within the cells of the plant are rapidly released once they reach the rumen. These proteins and particles are attacked by slime-producing rumen microbes, which cause a buildup of stable foam. The foam, often due to the presence of saponins, decreases the animal’s ability to expel rumen gases that are created from fermentation of plant material. These gases begin to accumulate, causing pressure on the diaphragm, leading to bloat.
Symptoms: Livestock suffering from bloat will begin to swell rapidly on the left side. Kicking at their sides or stomping their feet are other signs the animal is experiencing discomfort. Breathing may be labored, and urination and defecation frequent. In severe cases, the rumen can become distended, and death may occur.
Plants causing bloat include alfalfa, clovers, brassi-cas, cultivated grains, and sweetclovers.
Symptoms: The injury may result in sores and inflammation on the tongue, gums, eyes, nose, and skin. Sores can lead to localized skin infections or a general infection from bacteria entering the circulatory system. Additional injuries include plant fibers that may lodge in the stomach or intestines and fibers imbedded in eyelids causing lesions to the eyeball. Animals suffering mechanical injury may stop eating and develop a poor condition.
Plants causing mechanical injuries include bristle-grass, cheatgrass, needlegrasses, foxtail barley, rye, wild oats, burdock, and cactus.
Mycotoxins Mycotoxins are toxins produced by mold (fungi). The host plant itself may not be toxic (e.g. alsike clover, sweetclover), but toxicity problems can occur with improper feed (seeds, hay, silage) harvest and storage. Some fungi cause toxicity problems in specific plant species (e.g. perennial ryegrass, tall fescue, lupine). Major classes of mycotoxins include aflatoxins, trichothecenes, fumonisins, zearalenone, ochratoxin, and ergot alkaloids (e.g. endophyte-infested fescue, swainsonine).
Symptoms: Symptoms will vary depending on the mold involved. Mycotoxins in lupine can cause severe liver, kidney and muscle disease. Ergot alkaloids in tall fescue cause vasoconstriction at the extremities, elevated respiration
Mechanical InjuriesMechanical injuries are physical issues caused by spines, sharp seeds, burs, and awns. The plant may not be poisonous, but the injuries can cause symptoms that resemble a toxin effect.
Photo: M. Lavin, MSU
Photo: USDA-NRCS
- 20 -
rate, convulsions, lameness and tenderness of the legs, poor hair condition, loss of extremities (hooves, ears, tails), decrease in milk production, difficult births, and abortion.
Plants commonly containing mycotoxins include alsike clover, red clover, corn, sweetclovers, perennial ryegrass, tall fescue, and lupine.
Photosensitization Photosensitization can be caused from consuming plant species containing light-sensitive compounds that, once absorbed in the gastrointestinal tract, circulate in the blood. In primary photosensitization, photodynamic compounds accumulate in blood vessels at the skin surface, particularly in non-pigmented skin, and ultraviolet light transforms compounds into toxins. As a result, skin becomes abnormally sensitive to sunlight causing severe inflammation and damage. Secondary photosensitization, which is more common than primary photosensitization, is caused by a variety of plant toxins that cause liver damage or liver disease. The damaged liver cannot excrete phylloerythrin (a bacterial breakdown of chlorophyll), and it accumulates in the bloodstream. As phylloerythrin circulates and is exposed to ultraviolet light, it causes oxidative injury to blood vessels and skin tissue. Animals do not readily eat plants containing liver-damaging substances (e.g. pyrrolizidine alkaloids) unless they lack quality forage or are exposed to plants in hay. Since ingesting damaging substances is cumulative, liver disease and associated photosensitization may take many months to appear.
Symptoms: Signs of primary photosensitization include severe skin irritation, photophobia (e.g. seeking shade), rubbing and shaking the head, excessive eye tearing and discharge, redness of non-pigmented skin, increased sensitivity of skin, and swelling around ears, eyelids, lips, and nose. Skin can ooze serum, form crusts, lose hair, and slough white skin. Lameness can occur from impacts to hooves. Secondary photosensitization, in addition to symptoms of primary photosensitization, includes signs of liver failure such as weight loss, neurologic signs (e.g. yawning, drowsiness, aimless wandering, head pressing, increased licking, and coma), jaundice, abdominal distention, and diarrhea.
St. Johnswort (Hypericum perforatum), identified by the five-petaled yellow flowers with black glands on the petal margins, can form dense patches in mountains, foothills, rangelands and disturbed areas. Animals that eat St. Johnswort and are exposed to direct sunlight develop photosensitization in the white areas of the body. Affected animals should be moved out of direct sunlight and provided free access to fresh water and feed.
Plants causing photosensitization: Plants associated with primary photosensitization are buckwheat, St. Johnswort, and cow parsnip. Plants associated with liver damage leading to photosensitization include horsebrush, tansy ragwort, groundsel, fiddleneck, houndstongue, and blueweed. In addition, moldy plants and blue-green algae can cause liver damage from photosensitization.
Volatile Oils Volatile oils are organic compounds that readily vaporize or evaporate. They are responsible for a plant’s odor and a bitter taste, and, in some plants, are part of the plant’s defense to herbivory and insects. Toxicity varies with plant species.
Symptoms: Livestock exposed to plants with volatile oils may have dermatitis or skin and mucous membrane irritation. When ingested, volatile oils may cause digestive tract irritation, vomiting, reduced rumen activity, damage to the mucous lining of the digestive tract, nervousness, altered milk taste, and diarrhea.
Plants containing volatile oils include sagebrush, sagewort, buttercup, and horseweed.
Photo: T. Nelson, USDA-NRCS
Photo: T. Nelson, USDA-NRCS
- 21 -
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iarr
hea,
red-
colo
red
urin
e,
and
pulm
onar
y em
phys
ema,
hem
olyt
ic a
nem
ia, p
ulm
onar
y em
phys
ema,
blin
dnes
s, s
tagg
erin
g, d
epre
ssio
n, re
duce
d w
eigh
t ga
inBi
rdsf
oot t
refo
il(L
otus
cor
nicu
latu
s)X
Xal
lal
lni
trate
, cya
noge
nic
glyc
osid
e (H
CN
)al
l sys
tem
sSu
dden
dea
th, i
ncre
ased
sal
ivat
ion,
hea
vy b
reat
hing
Blac
k he
nban
e(H
yosc
yam
us n
iger
)X
Xal
lno
dat
aal
kalo
idga
stro
inte
stin
al,
mus
culo
skel
etal
, ne
rvou
s
Inte
stin
al s
tasi
s, c
onvu
lsio
ns, a
taxi
a, c
olic
, blo
at, d
iarr
hea,
de
crea
sed
saliv
atio
n, d
ilate
d pu
pils
, inc
reas
ed h
eart
rate
Blue
wee
d(E
chiu
m v
ulga
re)
XX
all
no d
ata
alka
loid
, ph
otos
ensi
tizat
ion
inte
gum
enta
ry, l
iver
, m
uscu
losk
elet
al,
nerv
ous,
ocu
lar
Seve
re w
eigh
t los
s, m
uscl
e at
roph
y, p
hoto
sens
itivi
ty, j
aund
ice,
in
coor
dina
tion,
dep
ress
ion,
aim
less
wan
derin
g, h
ead
pres
sing
, ey
e te
arin
gBo
unci
ngbe
t(S
apon
aria
offi
cina
lis)
XX
Xse
eds
sum
mer
, fa
llsa
poni
nga
stro
inte
stin
al, l
iver
Dec
reas
ed ru
men
act
ivity
, col
ic, a
nore
xia,
exc
essi
ve s
aliv
atio
n,
diar
rhea
, liv
er to
xici
tyBr
acke
nfer
n*(P
terid
ium
aqu
ilinu
m)
XX
Xal
lsu
mm
er,
fall,
and
in
hay
glyc
osid
e,
thia
min
ase
card
iova
scul
ar,
nerv
ous,
ocu
lar,
rena
l
Dea
th, b
lindn
ess,
hem
orrh
ages
, dep
ress
ion,
nas
al a
nd re
ctal
bl
eedi
ng, b
lood
y ur
ine,
ane
mia
, hig
h fe
ver,
loss
of a
ppet
ite,
diffi
culty
bre
athi
ng, e
xces
sive
sal
ivat
ion
(cat
tle, s
heep
); co
nvul
sion
s, s
eizu
res,
wei
ght l
oss,
inco
ordi
natio
n, fa
st p
ulse
, cr
ouch
ing
stan
ce, w
eakn
ess
(hor
ses)
Tabl
e 1.
Sig
ns o
f poi
soni
ng a
nd c
ondi
tion
s un
der
whi
ch p
lant
spe
cies
can
be
dang
erou
s to
live
stoc
k. S
ympt
oms
liste
d fo
r ea
ch p
lant
are
thos
e m
ost l
ikel
y to
be
obse
rved
. N
ot a
ll sy
mpt
oms
will
be
seen
in a
ll to
xici
ties
, and
sig
ns o
f poi
soni
ng m
ay v
ary
grea
tly
depe
ndin
g on
dos
age
and
the
tim
e ta
ken
to c
onsu
me
the
dose
. Als
o, in
divi
dual
an
imal
s re
spon
d di
ffere
ntly
to s
peci
fic to
xins
.
- 22 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Bras
sica
s –
cano
la, k
ale,
ra
dish
, tur
nip
(Bra
ssic
a sp
p.),
radi
sh (R
apha
nus
sativ
us)
XX
Xal
l; to
psfa
llbl
oat,
nitra
te,
cyan
ogen
ic
glyc
osid
e (H
CN
), m
ycot
oxin
card
iova
scul
ar,
gast
roin
test
inal
, m
uscu
losk
elet
al,
nerv
ous,
resp
irato
ry
Dea
th, b
loat
, goi
ter,
cong
estio
n of
rum
en a
nd a
bom
asum
, hy
poth
yroi
dism
, blin
dnes
s, d
iarr
hea,
red-
colo
red
urin
e, a
nd
hem
olyt
ic a
nem
ia, p
ulm
onar
y em
phys
ema,
blin
dnes
s, s
tagg
erin
g,
depr
essi
on, r
educ
ed w
eigh
t gai
nBu
ckth
orn
(Rha
mnu
s ca
thar
tica)
SX
fruit,
le
aves
sprin
g,
sum
mer
, fa
ll
glyc
osid
ega
stro
inte
stin
alN
ause
a, s
tom
ach
cram
ps, v
omiti
ng, d
iarr
hea
Buck
whe
at
(Fag
opyr
um e
scul
entu
m)
XX
XX
all
sum
mer
, fa
ll, a
nd
in h
ay
frago
pyrin
, ph
otos
ensi
tizat
ion
inte
gum
enta
ry,
ocul
arPh
otos
ensi
tivity
, tea
ring
Butte
rcup
(Ran
uncu
lus
spp.
an
d C
erat
ocep
hala
te
stic
ulat
a)
XX
Xal
lal
lgl
ycos
ide,
vo
latil
e oi
lsga
stro
inte
stin
alA
bdom
inal
pai
n, ir
ritat
ion
of d
iges
tive
tract
, red
deni
ng o
f ora
l m
ucou
s m
embr
anes
, dia
rrhe
a, e
xces
sive
sal
ivat
ion
Cho
kech
erry
*(P
runu
s vi
rgin
iana
) an
d P
in c
herr
y (P
. pe
nsyl
vani
ca)
XX
XR
all;
youn
g st
ems
& le
aves
, se
eds
sprin
g,
sum
mer
cyan
ogen
ic
glyc
osid
e (H
CN
)ga
stro
inte
stin
al,
card
iova
scul
ar,
resp
irato
ry, a
ll or
gans
Sudd
en d
eath
, com
a, c
onvu
lsio
ns, m
uscu
lar s
pasm
s, d
ifficu
lty
brea
thin
g, b
loat
, muc
ous
mem
bran
es a
ppea
r pin
k/re
d, v
enou
s bl
ood
is c
herr
y re
d, n
ervo
usne
ss, w
eakn
ess,
sta
gger
ing,
ex
cess
ive
saliv
atio
nC
love
r, al
sike
(T
rifol
ium
hyb
ridum
)X
XX
Xal
lal
lbl
oat,
myc
otox
in,
nitra
te,
phot
osen
sitiz
atio
n
inte
gum
enta
ry, l
iver
, ne
rvou
sBl
oat (
rum
inan
ts),
enla
rged
live
r, w
eigh
t los
s, p
hoto
sens
itivi
ty,
jaun
dice
, dep
ress
ion,
aim
less
wan
derin
g, w
alki
ng in
circ
les,
hea
d pr
essi
ng, y
awni
ngC
love
r, re
d(T
rifol
ium
pra
tens
e)X
XX
Xal
lal
lal
kalo
id, b
loat
, m
ycot
oxin
, nitr
ate,
ph
otos
ensi
tizat
ion
gast
roin
test
inal
, in
tegu
men
tary
, re
prod
uctiv
e
Bloa
t (ru
min
ants
), ex
cess
ive
saliv
atio
n, d
ehyd
ratio
n,
phot
osen
sitiv
ity, r
epro
duct
ion
prob
lem
s
Clo
ver,
whi
te(T
rifol
ium
repe
ns)
XX
XR
all
all
bloa
t, gl
ycos
ide,
ni
trate
, ph
otos
ensi
tizat
ion
gast
roin
test
inal
, in
tegu
men
tary
, m
uscu
losk
elet
al,
repr
oduc
tive,
re
spira
tory
Bloa
t (ru
min
ants
), m
uscu
lar t
rem
ors,
incr
ease
d re
spira
tory
rate
, st
agge
ring,
recu
mbe
ncy,
pho
tose
nsiti
vity
, dro
wsi
ness
, wea
knes
s,
repr
oduc
tion
prob
lem
s
Coc
kleb
ur*
(Xan
thiu
m s
trum
ariu
m,
X. s
pino
sum
)
XX
XX
spro
uts,
se
eds
sprin
g,
sum
mer
glyc
osid
ega
stro
inte
stin
al,
nerv
ous,
rena
l, liv
er
Sudd
en d
eath
, com
a, li
ver d
amag
e, c
onvu
lsio
ns, a
taxi
a,
inco
ordi
natio
n, v
omiti
ng, a
bdom
inal
pai
n, lo
ss o
f app
etite
, de
pres
sion
, wea
knes
s C
orn*
(Zea
may
s)X
XX
Rst
ems
sum
mer
, fa
llm
ycot
oxin
, nitr
ate,
se
leni
umca
rdio
vasc
ular
, ga
stro
inte
stin
al,
repr
oduc
tive,
re
spira
tory
Dea
th, c
onge
stio
n of
rum
en a
nd a
bom
asum
, mud
dy c
yano
tic
muc
us m
embr
anes
, sho
rtnes
s of
bre
ath,
cya
nosi
s, s
tagg
erin
g,
choc
olat
e-br
own
bloo
d, a
cido
sis,
wat
erin
g ey
es, r
educ
ed m
ilk
flow
, red
uced
wei
ght g
ain,
abo
rtion
, inf
ertil
ityC
ow p
arsn
ip
(Her
acle
um m
axim
um)
Xflo
wer
s,
seed
ssu
mm
er,
fall
fura
noco
umar
in,
phot
osen
sitiz
atio
nin
tegu
men
tary
Phot
osen
sitiv
ity
1 X =
kno
wn
affec
ts, R
= ra
rely
affe
cts,
S =
sus
pect
ed to
affe
ct
2 p
lant
par
t or t
ime
of y
ear;
mos
t sus
cept
ible
pla
nt p
art o
r mos
t dan
gero
us ti
me
of y
ear
* to
xic
dose
info
rmat
ion
avai
labl
e fo
r spe
cies
in T
able
2
Tabl
e 1,
(con
t.)
- 23 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Cur
lycu
p gu
mw
eed
(Grin
delia
squ
arro
sa)
XS
Xle
aves
no d
ata
sele
nium
inte
gum
enta
ry,
mus
culo
skel
etal
Hea
rt at
roph
y, li
ver f
ailu
re, l
amen
ess,
bon
e an
d jo
int
dege
nera
tion,
ane
mia
, red
uced
repr
oduc
tion
perfo
rman
ce, l
oss
of
long
hai
rs o
f the
mai
n an
d ta
il (h
orse
s, c
attle
); re
duct
ion
in fe
rtilit
y (s
heep
) D
eath
cam
as*
(Zig
aden
us s
pp.)
XX
XX
all;
bulb
, m
atur
e le
aves
all;
sprin
gal
kalo
idga
stro
inte
stin
al,
mus
culo
skel
etal
, ne
rvou
s
Sudd
en d
eath
, com
a, c
onvu
lsio
ns, a
taxi
a, p
rost
ratio
n, v
omiti
ng,
stag
gerin
g, lo
wer
ed te
mpe
ratu
re, e
xces
sive
sal
ivat
ion,
trem
ors,
la
bore
d br
eath
ing,
wea
knes
sD
ock,
cur
ly*
(Rum
ex c
rispu
s)X
XX
all;
leav
es,
stem
no d
ata
oxal
ate,
nitr
ate
mus
culo
skel
etal
, ga
stro
inte
stin
al,
rena
l
Sudd
en d
eath
, com
a, m
uscl
e tre
mor
s, k
idne
y fa
ilure
, abd
omin
al
pain
, inc
oord
inat
ion,
sal
ivat
ion,
dep
ress
ion,
wea
knes
s, re
luct
ance
to
mov
eD
ogba
ne*
(Apo
cynu
m c
anna
binu
m,
(A. a
ndro
saem
ifoliu
m)
XX
XX
leav
esal
l; ha
yca
rdia
c gl
ycos
ide
card
iova
scul
ar,
gast
roin
test
inal
, oc
ular
Sudd
en d
eath
, com
a, c
yano
sis,
irre
gula
r hea
rtbea
t, ra
pid
puls
e,
blue
col
orat
ion
of m
ucou
s m
embr
anes
, abd
omin
al p
ain,
vom
iting
, di
arrh
ea, w
eakn
ess,
dila
tion
of p
upils
Elde
rber
ry, r
ed*
(Sam
bucu
s ra
cem
osa)
XX
Ral
lfa
ll,
sprin
gcy
anog
enic
gl
ycos
ide
(HC
N)
card
iova
scul
ar,
nerv
ous,
re
prod
uctiv
e,
resp
irato
ry
Sudd
en d
eath
, abo
rtion
s, in
crea
sed
hear
t rat
e, in
crea
sed
resp
irato
ry ra
te, p
antin
g, o
pen
mou
th b
reat
hing
, ext
rem
e di
fficu
lty
brea
thin
g, v
enou
s bl
ood
is c
herr
y re
d, m
ucou
s m
embr
anes
brig
ht
red,
exc
item
ent
Fals
e he
llebo
re*
(Ver
atru
m s
pp.)
XX
Xal
l; le
aves
, ro
ots
sprin
g,
sum
mer
, fa
ll
alka
loid
gast
roin
test
inal
, ne
rvou
s,
repr
oduc
tive
Birth
def
ects
, abo
rtion
, com
a, c
onvu
lsio
ns, i
rreg
ular
hea
rtbea
t, pr
ostra
tion,
diffi
cult
resp
iratio
n, v
omiti
ng, e
xces
sive
sal
ivat
ion,
w
eakn
ess,
irre
gula
r gai
tFe
scue
, tal
l(S
ched
onor
us
arun
dina
ceus
)
XX
Xle
aves
, se
eds
sum
mer
, an
d in
ha
y
alka
loid
, myc
otox
in,
nitra
teca
rdio
vasc
ular
Gan
gren
e in
ext
rem
ities
(‘fe
scue
foot
’), im
paire
d re
prod
uctio
n an
d m
ilk p
rodu
ctio
n, h
eat s
tress
, fai
lure
to s
hed
win
ter c
oat (
cattl
e);
poor
repr
oduc
tion
(hor
ses)
Fidd
lene
ck*
(Am
sinc
kia
men
zies
ii,
(A. l
ycop
soid
es)
XR
RX
all
no d
ata
alka
loid
(p
yrro
lizid
ine)
, ph
otos
ensi
tizat
ion
Gas
troin
test
inal
, m
uscu
losk
elet
al,
nerv
ous,
ocu
lar,
rena
l, al
l sys
tem
s
Rec
tal p
rola
pse,
red
urin
e, e
dem
a of
the
legs
, pho
tose
nsiti
vity
, ph
otop
hobi
a, ja
undi
ce, w
eigh
t los
s, s
ever
e de
pres
sion
, aim
less
w
alki
ng, d
iarr
hea,
ince
ssan
t lic
king
of o
bjec
ts, h
ead
pres
sing
(c
attle
, hor
ses)
; wei
ght l
oss,
app
etite
loss
(she
ep, g
oats
)Fi
eld
bind
wee
d(C
onvo
lvul
us a
rven
sis)
Xal
l; se
eds
no d
ata
alka
loid
(tro
pane
)ga
stro
inte
stin
alC
olic
Fiel
d pe
nnyc
ress
(Thl
aspi
arv
ense
)X
all;
seed
sno
dat
agl
ycos
ide
gast
roin
test
inal
Dea
th, p
rofu
se s
wel
ling
of th
e fo
re s
tom
ach,
col
ic, b
lood
y di
arrh
ea, t
aint
ed m
ilkFl
ax(L
inum
spp
.)X
XX
Ral
lno
dat
acy
anog
enic
gl
ycos
ide
(HC
N)
card
iova
scul
ar,
resp
irato
ry
Sudd
en d
eath
, cya
nosi
s, c
herr
y-re
d ve
nous
blo
od, d
ifficu
lty
brea
thin
g, e
xces
sive
sal
ivat
ion,
ner
vous
ness
, wea
knes
sFl
ixw
eed
(Des
cura
inia
sop
hia)
Xal
l; yo
ung
plan
tssp
ring
unkn
own,
ph
otos
ensi
tizat
ion
gast
roin
test
inal
, in
tegu
men
tary
, m
uscu
losk
elet
al,
nerv
ous,
ocu
lar
Blin
dnes
s, s
ever
e ph
otos
ensi
tivity
, diffi
culty
che
win
g an
d sw
allo
win
g, w
eigh
t los
s, h
ead
pres
sing
1 X =
kno
wn
affec
ts, R
= ra
rely
affe
cts,
S =
sus
pect
ed to
affe
ct
2 p
lant
par
t or t
ime
of y
ear;
mos
t sus
cept
ible
pla
nt p
art o
r mos
t dan
gero
us ti
me
of y
ear
* to
xic
dose
info
rmat
ion
avai
labl
e fo
r spe
cies
in T
able
2
Tabl
e 1,
(con
t.)
- 24 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Gol
denb
anne
r(T
herm
opsi
s m
onta
na)
XS
all;
seed
po
dsal
l; ha
yal
kalo
idm
uscu
losk
elet
alD
eath
, ata
xia,
wea
knes
s, u
nabl
e to
sta
nd
Gra
ins,
cul
tivat
ed
(oat
s, b
arle
y, ry
e,
tritic
ale,
whe
at)
XX
XX
stem
ssp
ring,
fa
llbl
oat,
nitra
te,
myc
otox
in,
sele
nium
card
iova
scul
ar,
gast
roin
test
inal
, re
prod
uctiv
e,
resp
irato
ry
Dea
th, b
loat
(rum
inan
ts),
cong
estio
n of
rum
en a
nd a
bom
asum
, te
tany
, sho
rtnes
s of
bre
ath,
cya
nosi
s, s
tagg
erin
g, c
hoco
late
-br
own
bloo
d, w
ater
ing
eyes
, red
uced
wei
ght g
ain,
abo
rtion
, rap
id
puls
e, in
ferti
lity
Gre
asew
ood*
(Sar
coba
tus
verm
icul
atus
)
XX
XS
leav
es,
buds
sprin
g,
fall,
w
inte
r
oxal
ate
mus
culo
skel
etal
, re
nal
Dea
th, c
oma,
kid
ney
failu
re, r
ecum
benc
y, m
uscl
e tre
mor
s, te
tany
, lo
ss o
f app
etite
, slo
w p
ulse
, wea
knes
s, c
olla
pse,
inco
ordi
natio
n,
depr
essi
on, r
eluc
tanc
e to
mov
e, d
rool
ing
Gro
und
ivy
(Gle
chom
a he
dera
cea)
Xal
lsp
ring,
an
d in
ha
y
vola
tile
oils
resp
irato
ryS
wea
ting,
sal
ivat
ion,
labo
red
brea
thin
g, p
upil
dila
tion
Gro
undc
herr
y, lo
ngle
af(P
hysa
lis lo
ngifo
lia)
Xal
lsp
ring,
an
d in
ha
y
vola
tile
oils
resp
irato
ryS
wea
ting,
sal
ivat
ion,
labo
red
brea
thin
g, p
upil
dila
tion
Gro
unds
el*
(Sen
ecio
spp
.)X
RR
Xal
lal
lal
kalo
id
(pyr
roliz
idin
e),
phot
osen
sitiz
atio
n
All
syst
ems,
live
rD
eath
, rec
tal p
rola
pse,
hem
olys
is, r
ed u
rine,
ane
mia
, in
coor
dina
tion,
pho
tose
nsiti
vity
, sw
ellin
g an
d re
dnes
s to
ski
n ar
ound
eye
s, ja
undi
ce, d
iarr
hea,
dep
ress
ion,
circ
ling,
aim
less
w
ande
ring,
hea
d pr
essi
ng, e
xces
sive
tear
ing,
wea
knes
s, w
eigh
t an
d ap
petit
e lo
ssH
alog
eton
*(H
alog
eton
glo
mer
atus
)X
all
sprin
gte
trady
mol
, ph
otos
ensi
tizat
ion
hepa
tic,
inte
gum
enta
ry
Dea
th, a
borti
ons,
live
r sw
ellin
g an
d fa
ilure
, rap
id w
eak
puls
e, d
ifficu
lty b
reat
hing
, pro
stra
tion,
twitc
hing
, sec
onda
ry
phot
osen
sitiv
ity, r
edne
ss a
nd e
dem
a of
the
tissu
es o
f the
hea
d,
swel
ling
of h
ead
(ear
s, li
ps, f
ace)
, inc
oord
inat
ion,
ano
rexi
a,
depr
essi
on, l
aggi
ng b
ehin
d in
her
dH
emlo
ck, p
oiso
n*(C
oniu
m m
acul
atum
)X
XX
Xal
l; se
eds
all;
sprin
gal
kalo
idal
l sys
tem
sSu
dden
dea
th, a
borti
ons,
com
a, re
spira
tory
par
alys
is, b
irth
defe
cts,
ata
xia,
mus
cle
trem
ors,
cya
nosi
s, ra
pid
wea
k pu
lse,
in
coor
dina
tion,
abd
omin
al p
ain,
ner
vous
ness
, wea
knes
s,
saliv
atio
n, fr
eque
nt u
rinat
ion
and
defe
catio
n, d
ilate
d pu
pils
H
emlo
ck, w
ater
*(C
icut
a do
ugla
sii)
XX
XX
all;
root
ssp
ring
cicu
toxi
nm
uscu
losk
elet
al,
card
iova
scul
ar,
nerv
ous,
resp
irato
ry
Sudd
en d
eath
, com
a, s
ever
e co
nvul
sion
s, re
spira
tory
par
alys
is,
rapi
d pu
lse
and
brea
thin
g, m
uscl
e de
gene
ratio
n, e
xces
sive
sa
livat
ion,
vig
orou
s ch
ewin
g, te
eth
grin
ding
, dila
ted
pupi
ls
Hem
p (C
anna
bis
sativ
a)R
Xno
dat
ano
dat
aca
nnab
inoi
dga
stro
inte
stin
al,
mus
culo
skel
etal
Dea
th, c
oma,
into
xica
tion,
vom
iting
, sal
ivat
ion,
mus
cle
trem
ors,
at
axia
1 X =
kno
wn
affec
ts, R
= ra
rely
affe
cts,
S =
sus
pect
ed to
affe
ct
2 p
lant
par
t or t
ime
of y
ear;
mos
t sus
cept
ible
pla
nt p
art o
r mos
t dan
gero
us ti
me
of y
ear
* to
xic
dose
info
rmat
ion
avai
labl
e fo
r spe
cies
in T
able
2
Tabl
e 1,
(con
t.)
- 25 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Hor
sebr
ush*
(Tet
rady
mia
can
esce
ns)
Xal
lsp
ring
tetra
dym
ol,
phot
osen
sitiz
atio
nhe
patic
, in
tegu
men
tary
D
eath
, abo
rtion
s, li
ver s
wel
ling
and
failu
re, r
apid
wea
k pu
lse,
diffi
culty
bre
athi
ng, p
rost
ratio
n, tw
itchi
ng, s
econ
dary
ph
otos
ensi
tivity
, red
ness
and
ede
ma
of th
e tis
sues
of t
he h
ead,
sw
ellin
g of
hea
d (e
ars,
lips
, fac
e), i
ncoo
rdin
atio
n, a
nore
xia,
de
pres
sion
, lag
ging
beh
ind
in h
erd
Hor
seta
il*(E
quis
etum
spp
.)X
RS
Xal
lal
l; ha
yth
iam
inas
ega
stro
inte
stin
al,
nerv
ous
Dea
th, c
oma,
con
vuls
ions
, sei
zure
s, w
eakn
ess
and
inco
ordi
natio
n of
the
hind
legs
, rec
umbe
ncy,
wei
ght l
oss,
dep
ress
ion,
app
ear
blin
d an
d ha
ve d
ifficu
lty s
eein
g, d
iarr
hea
Hor
sew
eed,
Can
adia
n(C
onyz
a ca
nade
nsis
)S
Xal
lno
dat
avo
latil
e oi
ls, t
anni
c ac
id, g
allic
aci
din
tegu
men
tary
Irrita
ted
skin
, muc
ous
mem
bran
es, a
nd n
ostri
ls
Hou
ndst
ongu
e*(C
ynog
loss
um o
ffici
nale
)X
RR
Xal
lal
l; ha
yal
kalo
id
(pyr
roliz
idin
e),
phot
osen
sitiz
atio
n
inte
gum
enta
ry,
liver
, ner
vous
, m
uscu
losk
elet
al
Dea
th, r
ecta
l pro
laps
e, re
d ur
ine,
ede
ma
of le
gs, p
hoto
sens
itivi
ty,
jaun
dice
, wei
ght l
oss,
wal
king
in c
ircle
s, d
iarr
hea,
dep
ress
ion,
ex
cess
ive
yaw
ning
Huc
kleb
erry
, fal
se
(Men
zies
ia fe
rrug
inea
)X
XX
Xal
lsp
ring,
fa
llne
urot
oxic
di
terp
enoi
dca
rdio
vasc
ular
, ga
stro
inte
stin
alC
onvu
lsio
ns, r
ecum
benc
y, in
coor
dina
tion,
irre
gula
r hea
rtbea
t, hy
pote
nsio
n, c
olic
, vom
iting
, dep
ress
ion
Indi
an b
read
root
, si
lver
leaf
(Ped
iom
elum
ar
goph
yllu
m)
XX
XX
seed
sno
dat
aph
otos
ensi
tizat
ion
inte
gum
enta
ryPh
otos
ensi
tivity
Indi
an p
aint
brus
h(C
astil
leja
spp
.)R
Rst
emno
dat
ase
leni
umin
tegu
men
tary
, m
uscu
losk
elet
alLa
men
ess,
long
hai
rs o
f the
mai
n an
d ta
il br
eak
Iris,
Roc
ky M
ount
ain
(Iris
mis
sour
iens
isX
all
no d
ata
irisi
nga
stro
inte
stin
al,
inte
gum
enta
ryC
olic
, abd
omin
al p
ain,
bur
ning
sen
satio
n of
mou
th a
nd th
roat
, vo
miti
ng, d
iarr
hea,
irrit
ated
ski
nIri
s, y
ello
wfla
g(Ir
is p
seud
acor
us)
Xno
dat
ano
dat
agl
ycos
ide
gast
roin
test
inal
, in
tegu
men
tary
Abd
omin
al p
ain,
vom
iting
, dia
rrhe
a, ir
ritat
ed s
kin
Jim
sonw
eed*
(Dat
ura
stra
mon
ium
)X
XX
Xal
l; se
eds
no d
ata;
ha
yal
kalo
id (t
ropa
ne)
card
iova
scul
ar,
gast
roin
test
inal
, oc
ular
Col
ic, r
umen
sta
sis,
mus
cula
r tw
itchi
ng, p
aral
ysis
, res
pira
tory
pa
raly
sis,
inco
ordi
natio
n, e
xces
sive
thirs
t, lo
ss o
f app
etite
, blo
at
(rum
inan
ts),
incr
ease
d he
art r
ate,
dila
ted
pupi
ls, i
mpa
ired
visi
on,
subn
orm
al te
mpe
ratu
re, d
ry m
uzzl
e, d
ecre
ased
sal
ivat
ion
John
song
rass
*(S
orgh
um h
alep
ense
)X
XX
Xal
lal
l; w
ilted
, re
grow
th
cyan
ogen
ic
glyc
osid
e (H
CN
), ni
trate
all s
yste
ms
Sudd
en d
eath
, con
vuls
ions
, abo
rtion
s or
lim
b de
form
ities
, cy
anos
is, c
herr
y-re
d ve
nous
blo
od a
nd m
ucou
s m
embr
anes
, in
crea
sed
saliv
atio
n, d
ifficu
lt br
eath
ing,
ner
vous
ness
, wea
knes
s,
urin
ary
inco
ntin
ence
, ata
xia,
hin
d le
g w
eakn
ess
Kna
pwee
d, R
ussi
an*
(Acr
optil
on re
pens
)X
all;
gree
n pl
ants
no d
ata
DD
MP
gast
roin
test
inal
, re
spira
tory
, ner
vous
Dea
th fr
om s
tarv
atio
n, m
uscl
e tre
mor
s, fa
cial
par
alys
is, u
nabl
e to
take
hol
d of
and
che
w fo
od (c
hew
ing
dise
ase)
, inh
alat
ion
pneu
mon
ia, s
ever
e w
eigh
t los
s, in
coor
dina
tion,
deh
ydra
tion,
de
pres
sion
, exc
essi
ve s
aliv
atio
n1 X
= k
now
n aff
ects
, R =
rare
ly a
ffect
s, S
= s
uspe
cted
to a
ffect
2
pla
nt p
art o
r tim
e of
yea
r; m
ost s
usce
ptib
le p
lant
par
t or m
ost d
ange
rous
tim
e of
yea
r
*
toxi
c do
se in
form
atio
n av
aila
ble
for s
peci
es in
Tab
le 2
Tabl
e 1,
(con
t.)
- 26 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Koch
ia*
(Bas
sia
scop
aria
)X
XS
Xal
lal
l; ha
yni
trate
, oxa
late
, th
iam
inas
e, s
ulfa
te,
alka
loid
, sap
onin
, ph
otos
ensi
tizat
ion
all s
yste
ms;
kid
ney,
liv
erSu
dden
dea
th, b
lindn
ess,
kid
ney
failu
re, l
iver
dis
ease
, bro
wn
colo
red
muc
ous
mem
bran
es a
nd b
lood
, sev
ere
diffi
culty
br
eath
ing,
gas
troin
test
inal
infla
mm
atio
n, in
coor
dina
tion,
ph
otos
ensi
tivity
, dep
ress
ion,
dep
ress
ed a
ppet
ite, d
ehyd
ratio
n,
swol
len
eyel
ids,
cru
sty
muz
zle,
wei
ght l
oss
Labr
ador
tea
(Led
um g
land
ulos
um)
XX
XR
all
all;
win
ter
neur
otox
ic
dite
rpen
oid
gast
roin
test
inal
Con
vuls
ions
, inc
oord
inat
ion,
recu
mbe
ncy,
irre
gula
r hea
rtbea
t, hy
pote
nsio
n, c
olic
, vom
iting
, dep
ress
ion
Lam
bsqu
arte
rs*
(Che
nopo
dium
alb
um)
XX
Xal
lno
dat
ani
trate
, oxa
late
, su
lfate
repr
oduc
tive,
re
spira
tory
Sudd
en d
eath
, acu
te re
spira
tory
failu
re, a
borti
on
Lark
spur
*(D
elph
iniu
m s
pp.)
XR
Ral
l; ne
w
grow
th,
seed
s
sprin
g (lo
w),
sum
mer
(ta
ll)
alka
loid
(dite
rpen
e),
bloa
tm
uscu
losk
elet
al,
gast
roin
test
inal
, re
spira
tory
, ner
vous
Dea
th, m
uscu
lar o
r res
pira
tory
par
alys
is, t
rem
ors,
inco
ordi
natio
n,
stiff
ness
, sta
gger
ing,
fallin
g, m
uscl
e tre
mor
s, c
olla
pse,
blo
at,
wea
knes
s, n
ervo
usne
ss, r
egur
gita
tion,
vom
iting
, sal
ivat
ion
Laur
el(K
alm
ia p
olifo
lia)
XX
XX
all
sprin
g,
fall
neur
otox
ic
dite
rpen
oid
all s
yste
ms
Con
vuls
ions
, inc
oord
inat
ion,
recu
mbe
ncy,
irre
gula
r hea
rtbea
t, hy
pote
nsio
n, c
olic
, vom
iting
, dep
ress
ion
Leaf
y sp
urge
(Eup
horb
ia e
sula
)X
RR
Xsa
pno
dat
adi
terp
ene
este
rsga
stro
inte
stin
al,
inte
gum
enta
ry
Col
ic, v
omiti
ng, r
edde
ning
and
sw
ellin
g or
blis
terin
g of
the
skin
, ey
e irr
itatio
n, w
eigh
t los
s w
hen
excl
usiv
ely
fed
leaf
y sp
urge
, di
arrh
ea, e
xces
sive
sal
ivat
ion
Loco
wee
d*(O
xytro
pis
spp.
)X
XX
Xal
lal
l; ha
yal
kalo
id
(sw
ains
onin
e)ga
stro
inte
stin
al,
repr
oduc
tive,
co
ngen
ital,
nerv
ous,
ce
lls, l
iver
Birth
def
ects
, abo
rtion
s an
d fe
tal d
eath
, dec
reas
ed fe
rtilit
y,
cong
estiv
e he
art f
ailu
re, l
iver
dam
age,
inco
ordi
natio
n, s
tiff
and
irreg
ular
gai
t, ab
norm
al b
ehav
ior,
aggr
essi
vene
ss, l
oss
of
dire
ctio
n, e
xcita
bilit
y, w
eigh
t los
s, d
epre
ssio
n, w
eakn
ess,
sta
ring,
di
fficu
lty e
atin
g, e
xagg
erat
ed m
outh
mov
emen
t, du
ll co
atLu
pine
*(L
upin
us s
pp.)
XX
RS
all;
seed
sal
l; ha
yal
kalo
ids,
m
ycot
oxin
mus
culo
skel
etal
, ne
rvou
s, h
epat
ic,
repr
oduc
tive,
re
spira
tory
Dea
th, r
espi
rato
ry fa
ilure
, com
a, b
irth
defe
cts
(cro
oked
legs
, cle
ft pa
late
), ab
ortio
n, c
onvu
lsio
ns, i
ncoo
rdin
atio
n, d
ifficu
lt br
eath
ing,
m
uscl
e tw
itchi
ng, l
oss
of m
uscl
e co
ntro
l, le
thar
gy, h
ead
pres
sing
, de
pres
sion
, ner
vous
ness
, exc
essi
ve s
aliv
atio
n, d
ry c
oat
Mal
low
, com
mon
(Mal
va n
egle
cta)
Xle
aves
, se
edno
dat
aox
alat
e, n
itrat
em
uscu
losk
elet
al,
nerv
ous
Stag
gerin
g, la
men
ess
Mat
rimon
y vi
ne(L
yciu
m b
arba
rum
)X
Xno
dat
ano
dat
aal
kalo
id
(sol
anac
eous
)ga
stro
inte
stin
al,
nerv
ous
Dea
th, c
onvu
lsio
ns, v
omiti
ng, d
iarr
hea,
exc
item
ent
Milk
vetc
h*(A
stra
galu
s sp
p.)
(not
A. c
icer
)
XX
XX
all
all;
sprin
g,
sum
mer
alka
loid
(s
wai
nson
ine)
, se
leni
um, n
itrot
oxin
inte
gum
enta
ry,
mus
culo
skel
etal
, ne
rvou
s,
repr
oduc
tive
Dea
th, a
borti
ons,
birt
h de
fect
s, b
rain
hem
orrh
ages
, res
pira
tory
di
stre
ss, l
oad
brea
thin
g (ro
arin
g di
seas
e), c
olla
psed
lung
, de
crea
sed
mal
e fe
rtilit
y, b
lindn
ess,
wea
knes
s, lo
ss o
f con
trol
of h
ind
limbs
, pro
stra
tion,
col
laps
e, d
ecre
ased
bod
y co
nditi
on,
lam
enes
s, a
bnor
mal
beh
avio
r, lo
ss o
f dire
ctio
n, k
nock
ing
of h
ocks
an
d fe
et w
hen
wal
king
, bre
akin
g of
long
hai
rs o
f the
man
e an
d ta
il, s
past
ic ja
w m
ovem
ents
, dep
ress
ed, n
ervo
usne
ss1 X
= k
now
n aff
ects
, R =
rare
ly a
ffect
s, S
= s
uspe
cted
to a
ffect
2
pla
nt p
art o
r tim
e of
yea
r; m
ost s
usce
ptib
le p
lant
par
t or m
ost d
ange
rous
tim
e of
yea
r
*
toxi
c do
se in
form
atio
n av
aila
ble
for s
peci
es in
Tab
le 2
Tabl
e 1,
(con
t.)
- 27 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Milk
wee
d*(A
scle
pias
spp
.)X
XX
Xal
lal
l; ac
tivel
y gr
owin
g,
hay
card
iac
glyc
osid
e,
sele
nium
card
iova
scul
ar,
gast
roin
test
inal
, m
uscu
losk
elet
al,
nerv
ous,
resp
irato
ry
Dea
th, c
onvu
lsio
ns, s
eizu
res,
resp
irato
ry p
aral
ysis
, rec
umbe
ncy,
ra
pid
wea
k pu
lse,
diffi
cult
brea
thin
g w
ith g
runt
ing
soun
ds,
abdo
min
al p
ain,
col
ic, b
loat
(rum
inan
ts),
diar
rhea
sta
gger
ing,
w
eakn
ess,
mus
cle
trem
ors,
relu
ctan
ce to
sta
nd, i
ncoo
rdin
atio
n,
deep
dep
ress
ion,
ele
vate
d te
mpe
ratu
re, d
ilatio
n of
pup
ilsM
illet
(Pen
nise
tum
gla
ucum
)X
XX
stem
sfa
llni
trate
card
iova
scul
ar,
gast
roin
test
inal
, re
prod
uctiv
e,
resp
irato
ry
Dea
th, c
onge
stio
n of
rum
en a
nd a
bom
asum
, mud
dy c
yano
tic
muc
us m
embr
anes
, sho
rtnes
s of
bre
ath,
cya
nosi
s, s
tagg
erin
g,
choc
olat
e-br
own
bloo
d, w
ater
ing
eyes
, red
uced
milk
flow
, re
duce
d w
eigh
t gai
n, a
borti
on a
nd in
ferti
lity
Mon
ksho
od*
(Aco
nitu
m c
olum
bian
um)
XX
XX
all;
seed
s,
root
ssu
mm
eral
kalo
ids
card
iova
scul
ar,
gast
roin
test
inal
, m
uscu
losk
elet
al,
resp
irato
ry
Sudd
en d
eath
, rec
umbe
ncy,
incr
ease
d re
spira
tory
rate
, diffi
culty
br
eath
ing,
mus
cle
wea
knes
s, s
tagg
erin
g ga
it, b
loat
ing,
exc
essi
ve
saliv
atio
n
Mou
ntai
n m
ahog
any,
cu
rl-le
af a
nd tr
ue
(Cer
coca
rpus
ledi
foliu
s,C
. mon
tanu
s)
Ral
lno
dat
acy
anog
enic
gl
ycos
ide
(HC
N)
all s
yste
ms
Sudd
en d
eath
, abo
rtion
s, d
ifficu
lty b
reat
hing
(ope
n-m
outh
br
eath
ing)
, res
pira
tory
failu
re, c
olla
pse,
muc
ous
mem
bran
es
cher
ry-r
ed in
col
or, v
enou
s bl
ood
cher
ry re
d, n
ervo
usne
ss,
wea
knes
s, e
xcite
men
t, ex
cess
ive
saliv
atio
nN
ight
shad
e*(S
olan
um s
pp.)
XX
XX
all;
fruit,
le
aves
all
alka
loid
, nitr
ate
all s
yste
ms
Dea
th, c
oma,
blo
at (r
umin
ants
), sh
ock,
kid
ney
failu
re, m
uscl
e tre
mor
s, ir
regu
lar h
eart
rate
, wea
k pu
lse,
inco
ordi
natio
n, c
olic
, la
bore
d br
eath
ing,
jaun
dice
, wea
knes
s, d
iarr
hea,
dro
wsi
ness
, ex
cess
sal
ivat
ion,
dep
ress
ion,
dro
wsi
ness
, dila
ted
pupi
lsO
nion
*(A
llium
spp
.)X
RR
Xle
aves
sprin
g,
sum
mer
alka
loid
, sul
fide
card
iova
scul
ar,
resp
irato
ry, r
enal
Poss
ible
dea
th, r
ecum
benc
y, fa
st w
eak
puls
e, c
olla
pse,
in
crea
sed
resp
irato
ry ra
te, a
nem
ia, r
ed-b
row
n ur
ine,
pal
e m
ucou
s m
embr
anes
, wea
knes
s, s
tagg
erin
gPe
nste
mon
(Pen
stem
on s
pp.)
RR
Rle
aves
no d
ata
sele
nium
inte
gum
enta
ry,
mus
culo
skel
etal
La
men
ess
(hor
ses)
, circ
ular
ridg
es in
all
feet
, los
s of
long
hai
rs o
f m
ane
and
tail
Phea
sant
’s e
ye*
(Ado
nis
aest
ival
is)
RR
Xle
aves
, flo
wer
sno
dat
a gl
ycos
ide
card
iova
scul
ar,
gast
roin
test
inal
Sudd
en d
eath
, err
atic
hea
rtbea
t, co
lic, d
ecre
ased
gut
mot
ility,
di
arrh
ea, v
omiti
ngPi
ne, p
onde
rosa
*(P
inus
pon
dero
sa)
XR
Rne
edle
s,
bark
all;
win
ter,
sprin
g
isoc
upre
ssic
aci
dre
nal,
repr
oduc
tive
Abo
rtion
, con
geni
tal d
efec
ts, p
ersi
sten
tly re
tain
ed p
lace
nta,
rena
l fa
ilure
, inc
oord
inat
ion,
aim
less
wan
derin
g
Prin
cesp
lum
e(S
tanl
eya
pinn
ata)
XX
XX
leav
esno
dat
ase
leni
umin
tegu
men
tary
, m
uscu
losk
elet
al
Dea
th, l
amen
ess,
slo
ughi
ng o
f the
hoo
f (ho
rses
), ci
rcul
ar ri
dges
in
all f
eet,
loss
of l
ong
hairs
of t
he m
ane
and
tail
Punc
ture
vine
(Trib
ulus
terr
estri
s)X
Xle
aves
, st
ems
no d
ata
sapo
nin,
nitr
ate,
ph
otos
ensi
tizat
ion
hepa
tic,
inte
gum
enta
ry,
mus
culo
skel
etal
Lam
enes
s, b
iliary
sta
sis,
pho
tose
nsiti
vity
, jau
ndic
e; s
wel
ling
of
the
head
(she
ep)
1 X =
kno
wn
affec
ts, R
= ra
rely
affe
cts,
S =
sus
pect
ed to
affe
ct
2 p
lant
par
t or t
ime
of y
ear;
mos
t sus
cept
ible
pla
nt p
art o
r mos
t dan
gero
us ti
me
of y
ear
* to
xic
dose
info
rmat
ion
avai
labl
e fo
r spe
cies
in T
able
2
Tabl
e 1,
(con
t.)
- 28 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Purs
lane
(Por
tula
ca o
lera
cea)
RR
Ral
lno
dat
aox
alat
em
uscu
losk
elet
al,
rena
lD
eath
, com
a, k
idne
y fa
ilure
, mus
cle
trem
ors,
teta
ny, r
ecum
benc
y,
wea
knes
s, d
epre
ssio
n, re
luct
ance
to m
ove
Red
root
pig
wee
d*(A
mar
anth
us re
trofle
xus)
XX
XX
all
all
oxal
ate,
nitr
ate
gast
roin
test
inal
, m
uscu
losk
elet
al,
rena
l
Dea
th, r
enal
failu
re, fl
uid
arou
nd k
idne
ys, a
taxi
a, b
loat
(ru
min
ants
), re
cum
benc
y, m
uscl
e w
eakn
ess
and
trem
ors,
kn
uckl
ing
at th
e fe
tlock
join
ts, d
ecre
ased
rum
en a
ctiv
ityR
eed
cana
rygr
ass
(Pha
laris
aru
ndin
acea
)X
XX
leav
esfa
llal
kalo
id, n
itrat
e,
sele
nium
mus
culo
skel
etal
, ne
rvou
s, re
spira
tory
Dea
th, w
eakn
ess,
sta
gger
, inc
reas
ed re
spira
tory
rate
, inc
reas
ed
wat
er in
take
, red
uced
ani
mal
per
form
ance
, gra
ss te
tany
, dia
rrhe
aR
yegr
ass,
per
enni
al
(Lol
ium
per
enne
)X
XX
leav
esno
dat
aal
kalo
id,
myc
otox
in, n
itrat
e,
phot
osen
sitiz
atio
n
inte
gum
enta
ry,
nerv
ous
Inco
ordi
natio
n, c
olla
pse,
mus
cle
spas
ms,
sta
gger
ing
(ryeg
rass
st
agge
rs),
head
sha
king
, pho
tose
nsiti
vity
, gra
ss te
tany
Sage
, lan
cele
af(S
alvi
a re
flexa
)R
RR
stem
hay
nitra
tega
stro
inte
stin
al,
mus
culo
skel
etal
Col
ic, m
uscl
e w
eakn
ess,
dia
rrhe
a
Sage
, san
d an
d fri
nged
(Arte
mis
ia fi
lifol
ia,
A. f
rigid
a)
Xle
aves
fall,
w
inte
rla
cton
e,
mon
oter
pene
, vo
latil
e oi
ls
gast
roin
test
inal
, ne
rvou
sAt
axia
(fro
nt fo
requ
arte
rs),
fallin
g do
wn,
abn
orm
al b
ehav
ior,
circ
ling,
exc
itabl
e, u
npre
dict
able
Sage
brus
h, b
ig*
(Arte
mis
ia tr
iden
tata
)S
leav
esal
lla
cton
e, v
olat
ile o
ilsga
stro
inte
stin
al,
nerv
ous
Dea
th, a
borti
ons
Sage
wor
t, gr
een
and
whi
te(A
rtem
isia
dra
cunc
ulus
, A
. lud
ovic
iana
)
XX
leav
esno
dat
avo
latil
e oi
lsga
stro
inte
stin
al,
inte
gum
enta
rySk
in ir
ritat
ion,
redu
ced
rum
en a
ctiv
ity, v
omiti
ng, d
iarr
hea
Saltb
ush
(Atri
plex
spp
.)X
XX
leav
esno
dat
ase
leni
umin
tegu
men
tary
, m
uscu
losk
elet
al
Lam
enes
s, c
rack
ed o
r def
orm
ed h
oove
s, lo
ss o
f lon
g ha
irs o
f the
m
ane
and
tail
Scot
ch b
room
(Cyt
isus
sco
pariu
s)X
XX
no d
ata
no d
ata
alka
loid
gast
roin
test
inal
, m
uscu
losk
elet
alC
onge
nita
l mal
form
atio
ns, m
uscl
e de
gene
ratio
n, m
uscl
e tre
mor
s,
inco
ordi
natio
n, c
olic
, ano
rexi
a, e
xces
sive
sal
ivat
ion
Scra
mbl
ed e
ggs
(Cor
ydal
is a
urea
)X
Xno
dat
ano
dat
aal
kalo
idne
rvou
sSu
dden
dea
th, c
onvu
lsio
ns, r
estle
ssne
ss, t
witc
hing
of f
acia
l m
uscl
esSe
rvic
eber
ry*
(Am
elan
chie
r aln
ifolia
)X
XX
all;
not
berr
ies
sprin
g,
sum
mer
cyan
ogen
ic
glyc
osid
e (H
CN
)al
l sys
tem
sSu
dden
dea
th, a
borti
ons,
com
a, c
onvu
lsio
ns, c
olla
pse,
st
agge
ring,
diffi
culty
bre
athi
ng, m
ucou
s m
embr
anes
app
ear
pink
/red,
ven
ous
bloo
d is
che
rry
red,
exc
essi
ve s
aliv
atio
n,
nerv
ousn
ess,
exc
item
ent
Snak
ewee
d*(G
utie
rrez
ia s
arot
hrae
)X
XX
Xal
lsp
ring
sapo
nin,
sel
eniu
mga
stro
inte
stin
al,
mus
culo
skel
etal
re
prod
uctiv
e, li
ver
Abo
rtion
s, li
ver n
ecro
sis
and
dege
nera
tion,
dec
reas
ed m
ale
ferti
lity,
slo
ughi
ng o
f nas
al m
ucos
a, w
eigh
t los
s, s
tom
ach
pain
s,
diar
rhea
follo
wed
by
cons
tipat
ion
1 X =
kno
wn
affec
ts, R
= ra
rely
affe
cts,
S =
sus
pect
ed to
affe
ct
2 p
lant
par
t or t
ime
of y
ear;
mos
t sus
cept
ible
pla
nt p
art o
r mos
t dan
gero
us ti
me
of y
ear
* to
xic
dose
info
rmat
ion
avai
labl
e fo
r spe
cies
in T
able
2
Tabl
e 1,
(con
t.)
- 29 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Snee
zew
eed*
(Hym
enox
ys h
oope
sii)
RX
Ral
lsu
mm
er,
fall,
hay
sesq
uite
rpen
e la
cton
ega
stro
inte
stin
al,
mus
culo
skel
etal
re
spira
tory
Dea
th, r
umen
sta
sis,
ata
xia,
live
r deg
ener
atio
n, in
hala
tion
pneu
mon
ia, i
rreg
ular
pul
se, b
loat
, wei
ght l
oss,
lam
bs b
ecom
e st
iff a
nd w
aste
d, m
uscl
e tre
mor
s, d
ecre
ased
app
etite
, vom
iting
, de
hydr
atio
n, d
epre
ssio
n, w
eakn
ess,
teet
h gr
indi
ng, f
roth
ing
at
mou
th, c
ough
ing
Sorg
hum
s*, f
orag
e, g
rain
, so
rghu
m-s
udan
gras
s,
suda
ngra
ss(S
orgh
um b
icol
or, S
. x
drum
mon
dii,
S. b
icol
or
var.
suda
nene
se)
XX
XR
all
sum
mer
, fa
llni
trate
, cya
noge
nic
glyc
osid
e (H
CN
)ca
rdio
vasc
ular
, ga
stro
inte
stin
al,
repr
oduc
tive,
re
spira
tory
Dea
th, a
cido
sis,
con
gest
ion
of ru
men
and
abo
mas
um, m
uddy
or
red
cyan
otic
muc
us m
embr
anes
, sho
rtnes
s of
bre
ath,
cya
nosi
s,
stag
gerin
g, c
hoco
late
-bro
wn
bloo
d, w
ater
ing
eyes
, red
uced
milk
flo
w, r
educ
ed w
eigh
t gai
n, a
borti
on a
nd in
ferti
lity
Sorr
el
(Oxa
lis s
pp.)
RR
RR
no d
ata
no d
ata
oxal
ate
mus
culo
skel
etal
, re
nal
Dea
th, c
oma,
kid
ney
failu
re, t
etan
y, re
cum
benc
y, m
uscl
e tre
mor
s,
wea
knes
s, d
epre
ssio
n, re
luct
ance
to m
ove
St. J
ohns
wor
t*(H
yper
icum
per
fora
tum
)X
XR
Xle
aves
, flo
wer
sal
l; sp
ring,
ha
y
hype
ricin
, ph
otos
ensi
tizat
ion
inte
gum
enta
ry
Phot
osen
sitiv
ity, r
edde
ning
and
ede
ma,
sev
ere
itchi
ng, b
liste
ring,
sl
ough
ing
of w
hite
ski
n, s
crat
chin
g he
ad; c
onvu
lsio
ns, r
apid
re
spira
tion
and
puls
e, lo
ss o
f con
ditio
n, e
leva
ted
tem
pera
ture
, cr
ouch
ing,
rest
less
ness
Suck
leya
, poi
son
(Suc
kley
a su
ckle
yana
)X
Xal
lsu
mm
ercy
anog
enic
gl
ycos
ide
(HC
N)
card
iova
scul
ar,
gast
roin
test
inal
, ne
rvou
s, re
spira
tory
re
prod
uctiv
e
Dea
th, a
borti
on, c
olla
pse,
pin
k or
red
muc
ous
mem
bran
es,
cher
ry-r
ed b
lood
, diffi
culty
bre
athi
ng, n
ervo
usne
ss, e
xcite
men
t, ex
cess
ive
saliv
atio
n, w
eakn
ess
Sunfl
ower
(H
elia
nthu
s sp
p.)
XX
Xst
ems
no d
ata
nitra
teca
rdio
vasc
ular
, ga
stro
inte
stin
al,
repr
oduc
tive,
re
spira
tory
Dea
th, c
onge
stio
n of
rum
en a
nd a
bom
asum
, mud
dy c
yano
tic
muc
us m
embr
anes
, sho
rtnes
s of
bre
ath,
cya
nosi
s, s
tagg
erin
g,
choc
olat
e-br
own
bloo
d, w
ater
ing
eyes
, red
uced
milk
flow
, re
duce
d w
eigh
t gai
n, a
borti
on, i
nfer
tility
Sw
eetc
love
r, ye
llow
and
w
hite
* (M
elilo
tus
offici
nalis
)
XR
Xm
oldy
fe
edha
ydi
coum
arol
, m
ycot
oxin
, blo
atal
l sys
tem
sA
ntic
oagu
lant
effe
cts;
dea
th, b
loat
(rum
inan
ts),
lam
enes
s, in
tern
al
and
exte
rnal
hem
orrh
agin
g (e
.g. n
ose,
eye
cha
mbe
r, du
ring
birth
ing)
, lar
ge s
wel
lings
ove
r pro
tube
rant
bod
y ar
eas,
ane
mia
, bl
oody
and
bla
ck fe
ces,
wea
knes
sS
wee
tpea
(Lat
hyru
s sp
p.)
Xno
dat
ano
dat
aun
know
nm
uscu
losk
elet
alLa
men
ess
Tans
y, c
omm
on(T
anac
etum
vul
gare
)S
SS
leav
esno
dat
aal
kalo
id, v
olat
ile
oils
card
iova
scul
ar,
gast
roin
test
inal
Abo
rtion
s, c
onvu
lsio
ns, r
apid
wea
k pu
lse,
sto
mac
h pa
in,
saliv
atin
gTa
nsy
mus
tard
(Des
cura
inia
pin
nata
)X
all
sprin
g,
sum
mer
unkn
own,
ph
otos
ensi
tizat
ion
gast
roin
test
inal
, in
tegu
men
tary
, ne
rvou
s, o
cula
r
Blin
dnes
s, d
ifficu
lty e
atin
g (to
ngue
app
ears
par
alyz
ed),
seve
re
phot
osen
sitiv
ity, w
eigh
t los
s, h
ead
pres
sing
, aim
less
wan
derin
g
1 X =
kno
wn
affec
ts, R
= ra
rely
affe
cts,
S =
sus
pect
ed to
affe
ct
2 p
lant
par
t or t
ime
of y
ear;
mos
t sus
cept
ible
pla
nt p
art o
r mos
t dan
gero
us ti
me
of y
ear
* to
xic
dose
info
rmat
ion
avai
labl
e fo
r spe
cies
in T
able
2
Tabl
e 1,
(con
t.)
- 30 -
Plan
t Spe
cies
Live
stoc
k A
ffect
ed1
Plan
t Pa
rt2
Tim
e Ye
ar2
Toxi
n or
Dis
orde
rO
rgan
or S
yste
m
Affe
cted
Sym
ptom
s
Cattle
Sheep
Goat
Horse
Tans
y ra
gwor
t*(S
enec
io ja
coba
ea)
XX
XX
all
sprin
g,
sum
mer
, ha
y
alka
loid
(p
yrro
lizid
ine)
, ph
otos
ensi
tizat
ion
all s
yste
ms
Rec
tal s
train
ing,
live
r cirr
hosi
s, fl
uid
build
up in
abd
omen
, bile
duc
t pr
olife
ratio
n, re
d ur
ine,
pho
tose
nsiti
vity
, sw
ellin
g an
d re
dnes
s to
sk
in a
roun
d ey
es, d
iarr
hea,
sto
mac
h pa
in, a
imle
ss w
ande
ring,
he
ad p
ress
ing,
exc
essi
ve te
arin
g, le
thar
gy, w
eakn
ess,
ane
mia
, in
coor
dina
tion,
dra
ggin
g re
ar fe
et, w
eigh
t los
s, a
ppet
ite lo
ss,
depr
essi
onTe
ff (E
ragr
ostis
tef)
XX
Xst
ems
fall
nitra
teca
rdio
vasc
ular
, ga
stro
inte
stin
al,
repr
oduc
tive,
re
spira
tory
Dea
th, c
onge
stio
n of
rum
en a
nd a
bom
asum
, mud
dy c
yano
tic
muc
us m
embr
anes
, sho
rtnes
s of
bre
ath,
cya
nosi
s, s
tagg
erin
g,
choc
olat
e-br
own
bloo
d, w
ater
ing
eyes
, red
uced
milk
flow
, re
duce
d w
eigh
t gai
n, a
borti
on a
nd in
ferti
lity
This
tle, C
anad
a(C
irsiu
m a
rven
se)
Rst
ems
no d
ata
nitra
teca
rdio
vasc
ular
, ga
stro
inte
stin
al,
repr
oduc
tive,
re
spira
tory
Dea
th, c
onge
stio
n of
rum
en a
nd a
bom
asum
, mud
dy c
yano
tic
muc
us m
embr
anes
, sho
rtnes
s of
bre
ath,
cya
nosi
s, s
tagg
erin
g,
choc
olat
e-br
own
bloo
d, w
ater
ing
eyes
, red
uced
milk
flow
, re
duce
d w
eigh
t gai
n, a
borti
on, i
nfer
tility
This
tle, R
ussi
an*
(Sal
sola
trag
us)
XS
stem
sno
dat
ani
trate
card
iova
scul
ar,
mus
culo
skel
etal
, re
prod
uctiv
e
Abo
rtion
s, fe
tal d
eath
, rec
umbe
ncy,
incr
ease
d he
art r
ate,
in
crea
sed
resp
irato
ry ra
te, d
ifficu
lty b
reat
hing
, bro
wn
colo
red
muc
ous
mem
bran
es, s
tagg
erin
g ga
it To
bacc
o, c
oyot
e*(N
icot
iana
atte
nuat
a)X
XX
Xal
l; gr
een
grow
thno
dat
aal
kalo
id (n
icot
ine)
gast
roin
test
inal
, m
uscu
losk
elet
al,
nerv
ous,
re
prod
uctiv
e
Birth
def
ects
, abo
rtion
, com
a, c
onvu
lsio
ns, p
aral
ysis
of t
he
mus
cles
of t
he re
spira
tory
and
car
diov
ascu
lar s
yste
m, m
uscl
e tre
mor
s, s
tagg
erin
g, in
coor
dina
tion,
dia
rrhe
a, e
xces
sive
sal
ivat
ion
Vetc
h, h
airy
(Vic
ia v
illos
a)X
Xal
l; se
eds
fall
nitra
te,
phot
osen
sitiz
atio
nca
rdio
vasc
ular
, ga
stro
inte
stin
al,
inte
gum
enta
ry,
nerv
ous
Dea
th, c
onvu
lsio
ns, h
yper
prot
eine
mia
, exc
essi
ve b
leed
ing,
blo
at
(cat
tle),
thic
keni
ng o
f ski
n, p
hoto
sens
itivi
ty, s
wol
len
lym
ph n
odes
, ab
norm
al b
ehav
ior,
diffi
culty
sta
ndin
g, it
chin
g an
d ru
bbin
g of
in
fect
ed a
reas
, dia
rrhe
a, p
oor a
ppet
ite, h
air l
oss
Whi
teto
p(C
arda
ria d
raba
)S
Sle
aves
, se
eds
fall
gluc
osin
olat
esen
docr
ine
Ant
i-thy
roid
sym
ptom
s
Yello
w s
tarth
istle
*(C
enta
urea
sol
stiti
alis
)X
all
all
DD
MP
gast
roin
test
inal
, re
spira
tory
, ner
vous
Dea
th fr
om s
tarv
atio
n, b
rain
nec
rosi
s, m
uscl
e tre
mor
s, fa
cial
m
uscl
es h
yper
toni
c (w
oode
n ex
pres
sion
), fa
cial
par
alys
is, u
nabl
e to
che
w fo
od o
r drin
k (c
hew
ing
dise
ase)
, mou
th h
eld
open
, to
ngue
pro
trude
s, in
hala
tion
pneu
mon
ia, s
ever
e w
eigh
t los
s,
inco
ordi
natio
n, d
ehyd
ratio
n, d
epre
ssio
n, e
xces
sive
sal
ivat
ion
Yew
*(T
axus
bre
vifo
lia)
XX
XX
all;
leav
esal
l; w
inte
ral
kalo
id (t
axin
e)ca
rdio
vasc
ular
, ga
stro
inte
stin
al,
mus
culo
skel
etal
, re
spira
tory
, ner
vous
Sudd
en d
eath
, com
a, c
ircul
ator
y fa
ilure
, con
vuls
ions
, slo
w
hear
t rat
e, g
astri
c di
stre
ss, m
uscl
e tre
mbl
ing,
vom
iting
, diffi
culty
br
eath
ing,
inco
ordi
natio
n, d
iarr
hea,
ner
vous
ness
, fat
igue
, dila
ted
pupi
ls1 X
= k
now
n aff
ects
, R =
rare
ly a
ffect
s, S
= s
uspe
cted
to a
ffect
2
pla
nt p
art o
r tim
e of
yea
r; m
ost s
usce
ptib
le p
lant
par
t or m
ost d
ange
rous
tim
e of
yea
r
*
toxi
c do
se in
form
atio
n av
aila
ble
for s
peci
es in
Tab
le 2
Tabl
e 1,
(con
t.)
- 31 -
Tabl
e 2.
Tox
ic d
oses
for
com
mon
ly d
iagn
osed
pla
nt p
oiso
ning
s in
Mon
tana
and
Wyo
min
g. S
ympt
oms
of li
vest
ock
pois
onin
g m
ay n
ot b
e ev
iden
t un
til a
toxi
c th
resh
old
is r
each
ed.
Plan
t Spe
cies
Toxi
c D
osag
e (b
w =
bod
y w
eigh
t; n/
a =
not a
pplic
able
)C
attle
Shee
p/G
oats
Hor
ses
Com
men
tsA
lfalfa
(Med
icag
o sa
tiva)
22 p
pm (s
elen
ium
) 10
,000
ppm
(nitr
ate)
10,0
00 p
pm (n
itrat
e)22
ppm
(sel
eniu
m)
Sele
nium
acc
umul
ated
in th
e le
aves
. Nitr
ate
leve
ls a
re h
ighe
r in
low
er s
talk
s an
d st
ems.
Arr
owgr
ass
(Trig
loch
in s
pp.)
0.1
- 1.5
% b
w0.
1 –
5.0%
bw
Rar
ely
affec
ted
Flow
erin
g sp
ikes
con
tain
twic
e th
e am
ount
of t
oxin
and
requ
ire h
alf t
he d
osag
e.
Plan
ts lo
se to
xici
ty w
ith d
ryin
g (e
.g. h
ay).
Plan
ts m
ore
toxi
c w
hen
stre
ssed
from
dr
ough
t or f
rost
.Br
acke
nfer
n(P
terid
ium
aqu
ilinu
m)
No
data
No
data
3 - 5
% b
wC
onsu
mpt
ion
for a
t lea
st 3
0 da
ys. L
ive
and
drie
d pl
ants
are
toxi
c. R
oots
and
yo
ung
shoo
ts w
ith h
ighe
st to
xici
ty.
Cho
kech
erry
(Pru
nus
virg
inia
na)
0.1
- 0.6
% b
w
0.1
- 0.4
% b
wR
arel
y aff
ecte
dC
onsu
mpt
ion
0.1
to 0
.6%
bw
of l
eave
s de
pend
ing
on g
row
th s
tage
or 0
.24%
bw
fres
h tw
igs
(leth
al).
Fres
h, b
ruis
ed, w
ilted
(dro
ught
or f
rost
), an
d dr
y le
aves
ar
e po
ison
ous.
You
ng le
aves
mor
e to
xic
than
mat
ure
leav
es. S
eed
ston
es a
re
pois
onou
s.C
ockl
ebur
(Xan
thiu
m s
pp.)
0.75
– 3
.0%
bw
0.75
– 3
.0%
bw
No
data
Con
sum
ptio
n of
fres
h gr
een
spro
uts
(cot
yled
on s
tage
) and
see
ds (b
urs)
. Tox
icity
is
not
pre
sent
in m
atur
e pl
ants
.C
orn
(Zea
may
s)0.
5 - 1
.5%
nitr
ate
0.5
- 1.5
% n
itrat
e0.
5 - 1
.5%
nitr
ate
Man
y fa
ctor
s aff
ect t
oxic
ity, b
ut g
ener
ally
0.0
5% b
w is
min
imum
leth
al d
ose.
Dea
thca
mas
(Zig
aden
us s
pp.)
1% b
w0.
5 - 2
.5%
bw
No
data
Con
sum
ptio
n of
gre
en p
lant
can
be
leth
al. T
oxic
risk
gre
ates
t at e
arly
veg
etat
ive
grow
th s
tage
s fo
llow
ed b
y th
e flo
wer
and
pod
sta
ges.
Doc
k, c
urly
(Rum
ex c
rispu
s)10
– 2
0 lb
s/da
yN
o da
taN
o da
taSi
gns
can
occu
r with
in 5
hou
rs o
f con
sum
ptio
n of
gre
en p
lant
, and
dea
th fo
llow
s w
ithin
a d
ay. A
ll pa
rts o
f the
pla
nt a
re to
xic.
Dog
bane
(Apo
cynu
m s
pp.)
0.03
- 0.
05%
bw
0.03
- 0.
06%
bw
0.03
- 0.
05%
bw
Toxi
c do
se d
epen
ds o
n ra
te o
f con
sum
ptio
n an
d di
gest
ion.
Dea
th m
ay o
ccur
6 to
12
hou
rs a
fter c
onsu
mpt
ion.
Drie
d pl
ants
rem
ain
toxi
c.El
derb
erry
, red
(Sam
bucu
s ra
cem
osa
0.25
% b
w0.
25%
bw
n/a
Inge
stio
n of
wilt
ed le
aves
can
cau
se d
eath
in 1
hou
r or l
ess.
New
gro
wth
and
re
-gro
wth
are
als
o to
xic.
Fals
e he
llebo
re(V
erat
rum
spp
.)N
o da
ta6
- 12
ozn/
aD
osag
e is
for l
eave
s an
d st
ems,
but
the
root
s ar
e 5
to 1
0 tim
es m
ore
pois
onou
s.
Pois
onou
s at
all
grow
th s
tage
s.Fi
ddle
neck
(Am
sinc
kia
spp.
)0.
1% b
wR
arel
y aff
ecte
d0.
1% b
wD
osag
e is
for c
onsu
mpt
ion
over
2 w
eeks
resu
lting
in li
ver d
isea
se. C
linic
al s
igns
m
ay n
ot a
ppea
r for
2 to
8 m
onth
s af
ter c
onsu
mpt
ion.
Gre
asew
ood
(Sar
coba
tus
verm
icul
atus
)1.
5 - 5
% b
w1.
5 - 5
% b
wN
o da
taTo
xic
if ea
ten
quic
kly
or w
hen
a m
ajor
com
pone
nt o
f liv
esto
ck d
iet.
Loss
es o
ccur
w
hen
eatin
g la
rge
quan
titie
s of
leav
es th
at h
ave
falle
n to
the
grou
nd in
the
fall
and
win
ter o
r new
gro
wth
in s
prin
g. In
crea
ses
in to
xici
ty a
s gr
owin
g se
ason
ad
vanc
es. C
an b
e va
luab
le fo
rage
if a
nim
als
are
adap
ted
to o
xala
te c
onta
inin
g pl
ants
and
con
sum
ed w
ith n
on-to
xic
fora
ge.
Gro
unds
el(S
enec
io s
pp.)
1 - 5
% b
w (a
cute
)20
0 –
300%
bw
(c
hron
ic)
1 - 7
% b
w (a
cute
)C
onsu
mpt
ion
of 1
– 5
% w
ithin
a fe
w d
ays
can
be le
thal
. Chr
onic
poi
soni
ng
caus
ed b
y ac
cum
ulat
ive
cons
umpt
ion
of a
tota
l int
ake
of 2
5 to
150
% b
w o
ver
seve
ral m
onth
s.
Hal
oget
on(H
alog
eton
glo
mer
atus
)0.
3 - 1
.5%
bw
0.3
- 1.5
% b
wR
arel
y aff
ecte
dBe
com
es m
ore
toxi
c as
gro
win
g se
ason
adv
ance
s. P
eak
toxi
city
at m
atur
ity.
Toxi
city
dep
ends
on
othe
r for
age
avai
labi
lity.
- 32 -
Plan
t Spe
cies
Toxi
c D
osag
e (b
w =
bod
y w
eigh
t; n/
a =
not a
pplic
able
)C
attle
Shee
p/G
oats
Hor
ses
Com
men
tsH
emlo
ck, p
oiso
n(C
oniu
m m
acul
atum
)0.
1 –
1.0%
bw
0.1
– 1.
0% b
w0.
1 –
1.0%
bw
Con
sum
ptio
n of
gre
en p
lant
(let
hal).
See
ds, e
spec
ially
whe
n im
mat
ure,
are
mor
e to
xic
than
oth
er p
lant
par
ts. R
emai
ns to
xic
whe
n dr
ied.
Hor
sebr
ush
(Tet
rady
mia
can
esce
ns)
n/a
0.5
- 1.2
5%n/
aSh
eep
are
mai
nly
affec
ted
by th
is p
lant
whe
n ea
ten
in c
onju
nctio
n w
ith b
lack
sa
gebr
ush
(Arte
mis
ia n
ova)
.H
orse
tail
(Equ
iset
um s
pp.)
Feed
con
tain
ing
>20%
hor
seta
il.R
arel
y aff
ecte
d.Fe
ed c
onta
inin
g >2
0% h
orse
tail.
Sym
ptom
s ap
pear
2 to
5 w
eeks
afte
r con
sum
ptio
n. F
resh
and
dry
pla
nts
are
toxi
c.
Hou
ndst
ongu
e(C
ynog
loss
um o
ffici
nale
)5
- 10%
bw
Rar
ely
affec
ted
2% o
f dry
mat
ter
inta
ke/d
ay
Hor
ses
that
con
sum
e ar
ound
1 p
lant
per
day
for 2
wee
ks s
how
sym
ptom
s.
Leth
al fo
r cat
tle w
hen
eatin
g 5%
or m
ore
of th
eir t
otal
dai
ly d
iet o
f mat
ure
plan
ts
for p
erio
ds e
xcee
ding
15
days
. Ji
mso
nwee
d(D
atur
a st
ram
oniu
m)
1 –
5% b
w o
f see
dsN
o da
ta0.
5% b
w o
f see
ds
for 1
0 da
ysTo
xins
pre
sent
in a
ll pl
ant p
arts
, inc
reas
ing
with
mat
urity
and
rem
ain
afte
r dr
ying
. See
ds h
ave
high
est c
once
ntra
tion.
Jo
hnso
ngra
ss(S
orgh
um h
alep
ense
)0.
25%
bw
0.25
% b
w0.
25%
bw
Inge
stio
n in
the
form
of w
ilted
leav
es c
an re
sult
in d
eath
in a
n ho
ur o
r les
s.
Kna
pwee
d, R
ussi
an(A
crop
tilon
repe
ns)
n/a
n/a
86 -
200%
bw
Con
sum
ptio
n ov
er 1
to 3
mon
ths.
Koch
ia(B
assi
a sc
opar
ia)
>50%
of d
iet
>50%
of d
iet
>50%
of d
iet
Toxi
city
var
ies
with
gro
wth
sta
ge. M
ore
prob
lem
s as
soci
ated
with
mat
ure,
dr
ough
ty p
lant
s.
Lam
bsqu
arte
rs(C
heno
podi
um a
lbum
)>1
% n
itrat
es>1
% n
itrat
esn/
aA
nim
als
impa
cted
afte
r con
sum
ing
plan
ts w
ith >
1% n
itrat
es.
Lark
spur
(Del
phin
ium
spp
.)0.
5 - 3
.5%
bw
Rar
ely
affec
ted
(3 –
21%
) bw
Rar
ely
affec
ted
Hig
hly
pala
tabl
e an
d hi
ghly
toxi
c to
cat
tle. T
oxic
ity fo
r bot
h lo
w a
nd ta
ll la
rksp
ur
is m
ost p
reva
lent
at fl
ower
ing
stag
e an
d de
crea
ses
afte
r see
d dr
op. T
oxic
ity
decl
ines
ove
r gro
win
g se
ason
. Fre
sh o
r drie
d pl
ants
toxi
c. S
eeds
rem
ain
toxi
c.Lo
cow
eed
(Oxy
tropi
s sp
p.)
30 -
50%
bw
in d
ry
wei
ght
No
data
81 lb
s in
4 -
6 w
eeks
Sym
ptom
s ap
pear
2 to
9 w
eeks
afte
r con
sum
ptio
n.
Lupi
ne(L
upin
us s
pp.)
0.1
- 1.5
% b
w
0.5
- 1.5
% b
wR
arel
y aff
ecte
dSp
ecie
s va
ry in
toxi
city
leve
ls. T
oxic
sub
stan
ces
thro
ugho
ut p
lant
and
co
ncen
trate
d in
see
ds. Y
oung
er p
lant
s m
ore
toxi
c th
an m
atur
e pl
ants
. See
d st
age
espe
cial
ly to
xic.
Sm
alle
r dos
es p
oiso
nous
if c
attle
eat
lupi
ne d
aily
for 3
to
7 da
ys.
Milk
vetc
h(A
stra
galu
s sp
p.)
(not
A. c
icer
)
0.2
- 0.8
% b
w8
ozN
o da
taTo
xic
dose
dep
ends
on
rate
of c
onsu
mpt
ion
and
dige
stio
n. A
ll pl
ant p
arts
and
gr
owth
sta
ges
are
toxi
c, fr
esh
or d
ried,
but
toxi
city
dec
reas
es a
s pl
ant m
atur
es
and
drie
s. L
ess
dang
erou
s af
ter s
eed
disp
ersa
l. M
ilkw
eed
(Asc
lepi
as s
pp.)
0.05
– 2
.0%
bw
0.05
– 2
.0%
bw
0.05
– 2
.0%
bw
Spec
ies
vary
in to
xici
ty le
vels
. Nar
row
leaf
spe
cies
are
the
mos
t tox
ic a
nd
broa
d-le
af s
peci
es re
lativ
ely
non-
toxi
c. T
oxic
ity ri
sk w
hen
plan
t is
activ
ely
grow
ing.
Ris
ks d
ecre
ase
with
dry
ing
but p
lant
rem
ains
toxi
c.
Mon
ksho
od
(Aco
nitu
m c
olum
bian
um)
No
data
No
data
0.07
5% b
w
All
parts
are
toxi
c w
ith ro
ots,
see
ds a
nd p
re-fl
ower
ing
leav
es h
ighe
st in
co
ncen
tratio
n.N
ight
shad
e(S
olan
um s
pp.)
0.1
- 0. 3
% b
w0.
1 - 0
.3%
bw
0.1
- 0.3
% b
wTo
xici
ty o
f the
leav
es a
nd fr
uit i
s pr
esen
t in
all g
row
th s
tage
s. H
ighe
r tox
icity
in
fall
than
spr
ing
and
in b
errie
s th
an le
aves
. Drie
d pl
ants
rem
ain
toxi
c.
Tabl
e 2,
(con
t.)
- 33 -
Plan
t Spe
cies
Toxi
c D
osag
e (b
w =
bod
y w
eigh
t; n/
a =
not a
pplic
able
)C
attle
Shee
p/G
oats
Hor
ses
Com
men
tsO
nion
(Alli
um s
pp.)
25%
of d
iet
Rar
ely
affec
ted
No
data
Toxi
city
incr
ease
s w
ith th
e pu
ngen
cy o
f oni
on.
Phea
sant
’s e
ye(A
doni
s ae
stiv
alis
)R
arel
y aff
ecte
d16
oz
gree
n w
eigh
tN
o da
taD
osag
e is
fata
l to
shee
p.
Pine
, pon
dero
sa
(Pin
us p
onde
rosa
)4.
8 - 6
lbs
dry
or
gree
n ne
edle
s or
ba
rk
Rar
ely
affec
ted
n/a
Cat
tle a
ppea
r to
eat n
eedl
es w
hen
stre
ssed
suc
h as
dur
ing
win
ter s
now
stor
ms
or s
horta
ge o
f for
age.
Con
sum
ptio
n pe
r day
for m
ore
than
3 d
ays
(abo
rtion
). C
attle
in la
st tr
imes
ter a
re m
ost s
usce
ptib
le.
Red
root
pig
wee
d(A
mar
anth
us re
trofle
xus)
0.5
- 1.5
% n
itrat
e0.
5 - 1
.5%
nitr
ate
0.5
- 1.5
% n
itrat
eM
any
fact
ors
affec
t tox
icity
, gen
eral
ly 0
.05%
bw
is m
inim
um le
thal
dos
e fo
r ni
trate
acc
umul
atio
n. O
xala
te le
vels
rem
ain
high
in d
ry p
lant
s.
Sage
brus
h, b
ig(A
rtem
isia
trid
enta
ta)
n/a
0.75
lbs
for 1
– 3
da
ysn/
aO
ccas
iona
lly to
xic
to s
heep
. Fou
nd to
be
leth
al in
exp
erim
ents
. For
mos
t sp
ecie
s, s
ageb
rush
is a
use
ful f
orag
e pl
ant.
Serv
iceb
erry
(Am
elan
chie
r aln
ifolia
)0.
1 - 0
.6%
bw
0.1
- 0.4
% b
wn/
aC
onsu
mpt
ion
0.1
to 0
.6%
bw
of l
eave
s de
pend
ing
on s
tage
of g
row
th o
r 0.2
4%
bw fr
esh
twig
s (le
thal
). W
ilted
leav
es m
ore
toxi
c th
an fr
esh
leav
es.
Snak
ewee
d(G
utie
rrez
ia s
arot
hrae
)10
- 20
% b
w10
- 20
% b
wN
o da
taC
onsu
mpt
ion
over
2 w
eeks
is le
thal
. Cat
tle a
bort
afte
r eat
ing
20 lb
s gr
een
wei
ght.
Gre
en a
nd d
ry p
lant
s to
xic.
Tox
icity
incr
ease
s on
san
dy s
oils
. Sn
eeze
wee
d(H
ymen
oxys
hoo
pesi
i)R
arel
y aff
ecte
d2
lbs
gree
n le
aves
Rar
ely
affec
ted
Con
sum
ptio
n da
ily fo
r 10
days
is le
thal
.
Sorg
hum
-sud
angr
ass,
and
su
dang
rass
(Sor
ghum
spp
.)
0.5
- 1.5
% n
itrat
e0.
5 - 1
.5%
nitr
ate
0.5
- 1.5
% n
itrat
eM
any
fact
ors
affec
t tox
icity
, but
gen
eral
ly 0
.05%
bw
is m
inim
um le
thal
dos
e.
St. J
ohns
wor
t(H
yper
icum
per
fora
tum
)1%
bw
4% b
wN
o da
taTo
xic
conc
entra
tions
var
y by
pla
nt p
heno
logy
and
loca
tion.
Tox
ic a
t all
grow
th
stag
es.
Sw
eetc
love
r, ye
llow
and
w
hite
(Mel
ilotu
s offi
cina
lis)
10 –
20
mg/
kg o
f fe
ed (1
00 d
ays)
; 60
– 7
0 m
g/kg
of
feed
(21
days
Rar
ely
affec
ted
10 –
20
mg/
kg o
f fe
ed (1
00 d
ays)
; 60
– 7
0 m
g/kg
of
feed
(21
days
)
Toxi
ns a
re fo
und
in m
oldy
feed
and
not
in a
pas
ture
set
ting.
Sw
eetc
love
r hay
ca
n re
mai
n to
xic
for 3
to 4
yea
rs a
nd c
an b
e us
ed if
dilu
ted
with
unc
onta
min
ated
fe
ed (1
:3).
Tans
y ra
gwor
t(D
escu
rain
ia p
inna
ta)
5 - 1
0% b
w
5% b
w3
- 7%
bw
Tota
l int
ake
of 2
5 to
50%
bw
ove
r sev
eral
mon
ths.
Hay
reta
ins
toxi
city
for
mon
ths.
This
tle, R
ussi
an(S
also
la tr
agus
)0.
5 - 1
.5%
nitr
ate
No
data
n/a
Man
y fa
ctor
s aff
ect t
oxic
ity, b
ut g
ener
ally
0.0
5% b
w is
min
imum
leth
al d
ose.
Toba
cco,
coy
ote
(Nic
otia
na a
ttenu
ata)
2% b
wN
o da
taN
o da
taC
onsu
mpt
ion
of 2
% b
w fr
esh
plan
t is
leth
al.
Yello
w s
tarth
istle
(Cen
taur
ea s
olst
itial
is)
n/a
n/a
86 -
200%
bw
Con
sum
ptio
n of
pla
nt g
reen
wei
ght o
ver s
ever
al w
eeks
cau
ses
impa
cts.
You
ng
hors
es m
ost s
usce
ptib
le.
Yew
(Tax
us b
revi
folia
)0.
5% b
w0.
5% b
w0.
1% b
wC
onsu
mpt
ion
of g
reen
or d
ry fo
liage
, bar
k, s
eeds
, and
aril
sur
roun
ding
see
ds
are
all t
oxic
. Fol
iage
is re
adily
eat
en b
y liv
esto
ck.
Tabl
e 2,
(con
t.)
- 34 -
Plan
t Spe
cies
Scie
ntifi
c N
ame(
s)Pl
ant F
amily
Lifeform1
Native2
Noxious3
Hab
itat
Hab
itat D
escr
iptio
n
Mountains
Foothills
Shrubland
Plains
Valleys
Wet Areas
Cropland
Disturbed
Alfa
lfaM
edic
ago
sativ
aFa
bace
aeF
IX
XX
Fiel
ds, r
oads
ides
Aly
ssum
, hoa
ryB
erte
roa
inca
naBr
assi
cace
aeF
IX
XX
XX
XM
eado
ws,
pas
ture
s, fi
elds
, roa
dsid
esA
rrow
gras
sTr
iglo
chin
mar
itim
a,T.
pal
ustri
sJu
ncag
inac
eae
GN
XX
XX
XD
amp,
wet
, mar
shy
area
s, ir
rigat
ed p
astu
res,
sal
ine
and
alka
line
soils
Aste
r, w
oody
Xylo
rhiz
a gl
abriu
scul
aAs
tera
ceae
FN
XX
Dry
alk
alin
e so
ils, c
lay
or b
ento
nitic
soi
l of s
tepp
e, b
adla
nds
Bane
berr
yA
ctae
a ru
bra
Ran
uncu
lace
aeF
NX
XX
XX
Moi
st s
oils
of f
ores
ts, a
long
stre
ams
Beet
, sug
arB
eta
vulg
aris
Che
nopo
diac
eae
FI
XC
ultiv
ated
Bird
sfoo
t tre
foil
Lotu
s co
rnic
ulat
usFa
bace
aeF
IX
XX
XR
oads
ides
, fiel
ds, p
astu
res
Blac
k he
nban
eH
yosc
yam
us n
iger
Sola
nace
aeF
IW
XX
XX
XX
Roa
dsid
es, fi
elds
, pas
ture
sBl
uew
eed
Ech
ium
vul
gare
Bora
gina
ceae
FI
MX
XX
XR
oads
ides
, fiel
ds, m
eado
ws,
rive
r gra
vel b
ars,
vac
ant l
otBo
unci
ngbe
t S
apon
aria
offi
cina
lisC
aryo
phyl
lace
aeF
IX
XR
oads
ides
, woo
dlan
ds, p
astu
res
Brac
kenf
ern
Pte
ridiu
m a
quili
num
Poly
podi
acea
eF
NX
XM
oist
to w
et fo
rest
, woo
dlan
ds a
nd m
eado
ws,
thic
kets
with
in
fore
sted
land
scap
es, a
long
stre
ams,
val
leys
to s
ubal
pine
Bras
sica
sB
rass
ica
spp.
, R
apha
nus
sativ
usBr
assi
cace
aeF
IX
XC
ultiv
ated
Buck
thor
nR
ham
nus
cath
artic
aR
ham
nace
aeS
IM
XX
XFi
elds
, woo
ded
area
s, v
acan
t lot
s, ri
paria
n co
rrid
ors
Buck
whe
atFa
gopy
rum
es
cule
ntum
Poly
gona
ceae
FI
XX
Cul
tivat
ed, r
epor
ted
to e
scap
e in
to d
istu
rbed
soi
ls a
nd
road
side
sBu
tterc
upR
anun
culu
s sp
p.
and
Cer
atoc
epha
la
test
icul
ata
Ran
uncu
lace
aeF
N, I
MX
XX
XX
XX
XM
oist
mea
dow
s, g
rass
land
s, ir
rigat
ed h
ay fi
elds
, alo
ng
road
s, la
wns
Che
rry,
pin
P
runu
s pe
nsyl
vani
caR
osac
eae
SN
XX
XX
Ope
n fo
rest
, woo
dlan
ds, t
hick
ets;
up
to lo
wer
sub
alpi
neC
hoke
cher
ryP
runu
s vi
rgin
iana
Ros
acea
eS
NX
XX
XX
Rip
aria
n th
icke
ts, f
ores
ts, p
ine
and
ash
woo
dlan
ds, r
ocky
sl
opes
, sto
ny s
oil o
f gra
ssla
nds
Clo
ver,
alsi
keTr
ifoliu
m h
ybrid
umFa
bace
aeF
IX
XX
XM
oist
are
as, r
oads
ides
, fiel
ds, p
astu
res
Clo
ver,
red
Trifo
lium
pra
tens
eFa
bace
aeF
IX
XX
XX
Mea
dow
s, fi
elds
, law
ns, r
oads
ides
, stre
amba
nks
Clo
ver,
whi
teTr
ifoliu
m re
pens
Faba
ceae
FI
XX
XM
eado
ws,
moi
st g
rass
land
s, ro
adsi
des,
fiel
dsC
ockl
ebur
Xant
hium
stru
mar
ium
, X
. spi
nosu
mAs
tera
ceae
FN
XX
XX
XSt
ream
bank
s, ro
adsi
des,
fiel
ds, f
arm
yard
s, p
ond
and
rese
rvoi
r edg
eC
orn
Zea
May
sPo
acea
eG
IX
Cul
tivat
ed, r
arel
y es
capi
ngC
ow p
arsn
ipH
erac
leum
max
imum
Api
acea
eF
NX
XX
XM
oist
soi
l of a
vala
nche
slo
pes,
thic
kets
, ope
n fo
rest
, w
oodl
ands
, ofte
n al
ong
stre
ams
Tabl
e 3.
Pla
nt fa
mily
, nat
ive
stat
us, n
oxio
us w
eed
desi
gnat
ion,
and
hab
itat
des
crip
tion
s fo
r po
ison
ous
plan
t spe
cies
in M
onta
na a
nd W
yom
ing.
1 G =
gra
ss /
gram
inoi
d / g
rass
-like
, F =
forb
/ br
oadl
eaf p
lant
, S =
shr
ub, T
= tr
ee
2 N
= N
ativ
e, I
= In
trodu
ced
to M
onta
na a
nd W
yom
ing
3 Sta
te-li
sted
nox
ious
wee
d in
Mon
tana
(M),
Wyo
min
g (W
), or
bot
h (B
).
- 35 -
1 G =
gra
ss /
gram
inoi
d / g
rass
-like
, F =
forb
/ br
oadl
eaf p
lant
, S =
shr
ub, T
= tr
ee
2 N
= N
ativ
e, I
= In
trodu
ced
to M
onta
na a
nd W
yom
ing
3 Sta
te-li
sted
nox
ious
wee
d in
Mon
tana
(M),
Wyo
min
g (W
), or
bot
h (B
).
Plan
t Spe
cies
Scie
ntifi
c N
ame(
s)Pl
ant F
amily
Lifeform1
Native2
Noxious3
Hab
itat
Hab
itat D
escr
iptio
n
Mountains
Foothills
Shrubland
Plains
Valleys
Wet Areas
Cropland
Disturbed
Cur
lycu
p gu
mw
eed
Grin
delia
squ
arro
saAs
tera
ceae
FN
XX
XX
XM
argi
ns o
f wet
land
s, s
tream
bank
s, ro
adsi
des,
dis
turb
ed
site
s, v
erna
lly m
oist
Dea
thca
mas
Ziga
denu
s sp
p.Li
liace
aeF
NX
XX
XX
XM
any
spec
ies
in M
T an
d W
Y th
at v
ary
in h
abita
t; M
eado
ws,
op
en fo
rest
, alo
ng s
tream
s, s
tony
cal
care
ous
soil,
ridg
es,
gras
slan
ds, a
nd s
ageb
rush
ste
ppe;
up
to s
ubal
pine
Doc
k, c
urly
Rum
ex c
rispu
sPo
lygo
nace
aeF
IX
XX
XX
XM
oist
to w
et, d
istu
rbed
site
s, d
itche
s, ro
ads,
stre
ams,
w
etla
nds
Dog
bane
Apo
cynu
m
cann
abin
um, A
. an
dros
aem
ifoliu
m
Apo
cyna
ceae
FN
XX
XX
XR
ocky
soi
l, al
ong
stre
ams,
fore
st o
peni
ngs,
ope
n w
oode
d ar
eas,
mea
dow
s, ro
adsi
des
Elde
rber
ryS
ambu
cus
spp.
Cap
rifol
iace
aeS
NX
XX
XM
oist
ope
n fo
rest
and
woo
dlan
ds, t
hick
ets,
ava
lanc
he
slop
es, a
long
stre
ams;
val
leys
to s
ubal
pine
Fals
e he
llebo
reVe
ratru
m s
pp.
Lilia
ceae
FN
XX
Wet
ripa
rian
mea
dow
s, th
icke
ts, m
oist
fore
st o
peni
ngs,
av
alan
che
slop
es; u
p to
sub
alpi
neFe
scue
, tal
l S
ched
onor
us
arun
dina
ceus
Poac
eae
GI
XX
XM
oist
mea
dow
s, p
astu
res,
ditc
h ba
nks
and
irrig
ated
fiel
ds
Fidd
lene
ckA
msi
ncki
a m
enzi
esii,
A. l
ycop
soid
esBo
ragi
nace
aeF
NX
XX
Dry
soi
ls, c
ultiv
ated
are
as, r
oads
ides
, law
ns, p
astu
res
Fiel
d bi
ndw
eed
Con
volv
ulus
arv
ensi
sC
onvo
lvul
acea
eF
IB
XX
XX
Fiel
ds, p
astu
res,
vac
ant l
ots,
road
side
s Fl
ax
Linu
m s
pp.
Lina
ceae
FN
, IX
XX
XX
XG
rass
land
s, s
ageb
rush
ste
ppe,
bad
land
s, w
oodl
ands
, m
eado
ws,
fellfi
elds
, roa
dsid
esFl
ixw
eed
Des
cura
inia
sop
hia
Bras
sica
ceae
FI
XX
XX
XX
Dis
turb
ed s
oils
of fi
elds
, roa
dsid
es, p
astu
res
Gol
denb
anne
rTh
erm
opsi
s m
onta
na,
T. rh
ombi
folia
Faba
ceae
FN
XX
XX
XX
Moi
st m
eado
ws,
thic
kets
, woo
dlan
ds, s
ageb
rush
ste
ppe,
fo
rest
, alo
ng s
tream
, pas
ture
sG
rain
s, c
ultiv
ated
Poac
eae
GI
XX
Cul
tivat
edG
reas
ewoo
dS
arco
batu
s ve
rmic
ulat
usC
heno
podi
acea
eS
NX
XX
Salin
e so
il of
stre
am te
rrac
es, b
adla
nds,
dry
alk
alin
e so
ils
Gro
und
ivy
Gle
chom
a he
dera
cea
Lam
iace
aeF
IX
XX
Shad
ed, m
oist
soi
l of f
arm
yard
s an
d pa
stur
es, s
tream
bank
sG
roun
dche
rry,
lo
ngle
afP
hysa
lis lo
ngifo
liaSo
lana
ceae
FN
XX
XD
ry s
oils
of g
rass
land
s, fi
elds
, roa
dsid
es
Gro
unds
elS
enec
io s
pp.
Aste
race
aeF
N, I
XX
XX
Hay
fiel
ds, r
oads
ides
, far
mya
rds,
was
te a
reas
Hal
oget
onH
alog
eton
glo
mer
atus
Che
nopo
diac
eae
FI
XX
XX
Barr
en a
reas
, sal
ine
soil
of a
rid a
reas
, dis
turb
ed s
tepp
e in
ar
id v
alle
ys, d
ry la
kebe
ds, a
band
oned
dry
farm
fiel
dsH
emlo
ck, p
oiso
nC
oniu
m m
acul
atum
Api
acea
eF
IX
XX
Moi
st, d
istu
rbed
soi
l alo
ng s
tream
s, d
itche
s, c
ool o
pen
slop
es
Tabl
e 3,
(con
t.)
- 36 -
Plan
t Spe
cies
Scie
ntifi
c N
ame(
s)Pl
ant F
amily
Lifeform1
Native2
Noxious3
Hab
itat
Hab
itat D
escr
iptio
n
Mountains
Foothills
Shrubland
Plains
Valleys
Wet Areas
Cropland
Disturbed
Hem
lock
, wat
erC
icut
a do
ugla
sii
Api
acea
eF
NX
XX
XW
et m
eado
ws,
mar
shes
, alo
ng s
tream
s, w
etla
nds
Hem
pC
anna
bis
sativ
aC
anna
bace
aeF
IX
XX
XFi
elds
, roa
dsid
esH
orse
brus
hTe
trady
mia
can
esce
nsAs
tera
ceae
SN
XX
XX
Gra
ssla
nds,
dry
sag
ebru
sh s
tepp
e an
d gr
assl
ands
Hor
seta
ilE
quis
etum
spp
.Eq
uise
tace
aeF
NX
XX
XX
Moi
st to
wet
soi
l mea
dow
s, p
astu
res,
fore
sts,
stre
amba
nks,
la
ke s
hore
s at
all
elev
atio
nsH
orse
wee
d,
Can
adia
nC
onyz
a ca
nade
nsis
Aste
race
aeF
NX
XX
Dis
turb
ed m
eado
ws,
rang
elan
ds, g
rass
land
s, ro
adsi
des
Hou
ndst
ongu
eC
ynog
loss
um o
ffici
nale
Bora
gina
ceae
FI
BX
XX
XX
XX
XD
istu
rbed
gro
und
of p
astu
res,
fiel
ds, r
oads
ides
, gra
ssla
nds,
m
eado
ws,
woo
dlan
ds, f
ores
ts, r
ipar
ian
area
sH
uckl
eber
ry, f
alse
Men
zies
ia fe
rrug
inea
Eric
acea
eS
NX
XX
Coo
l, m
oist
, upl
and
slop
es in
con
ifero
us fo
rest
s, fo
rmin
g de
nse
thic
kets
on
north
slo
pes;
val
leys
to s
ubal
pine
Indi
an b
read
root
, si
lver
leaf
Ped
iom
elum
ar
goph
yllu
mFa
bace
aeF
NX
XX
Dry
gra
ssla
nds,
sag
ebru
sh s
tepp
e, d
eser
t shr
ubla
nd,
road
side
s, a
nd w
oodl
ands
; ofte
n in
san
dy s
oils
In
dian
pai
ntbr
ush
Cas
tille
ja s
pp.
Scro
phul
aria
ceae
FN
XX
XX
XM
oist
gra
ssla
nds,
sag
ebru
sh s
tepp
e, m
oist
to w
et m
eado
ws,
th
icke
ts, f
ores
t ope
ning
s, n
ear s
tream
s; u
p to
alp
ine
Iris,
Roc
ky
Mou
ntai
nIri
s m
isso
urie
nsis
Irida
ceae
FN
XX
XX
XM
oist
to w
et m
eado
ws,
thic
kets
, woo
dlan
d m
argi
ns
Iris,
yel
low
flag
Iris
pseu
daco
rus
Irida
ceae
FI
MX
XM
arsh
es, w
et m
eado
ws,
wet
land
s, s
tream
ban
ks, i
rrig
atio
n di
tche
sJi
mso
nwee
dD
atur
a st
ram
oniu
mSo
lana
ceae
FI
XX
XD
istu
rbed
soi
ls, r
oads
ides
, rai
lroad
righ
ts-o
f-way
, far
mya
rds,
cu
ltiva
ted
area
sJo
hnso
ngra
ss
Sor
ghum
hal
epen
sePo
acea
eG
IX
XX
Moi
st s
oils
of d
istu
rbed
site
s, ro
adsi
des,
ditc
hes,
was
te
area
s, a
lluvi
al b
otto
m la
nd, c
ultiv
ated
fiel
ds, p
astu
res
Kna
pwee
d,
Rus
sian
A
crop
tilon
repe
nsAs
tera
ceae
FI
BX
XX
XX
Fiel
ds, g
rass
land
s, m
eado
ws,
road
side
s, s
tream
terr
aces
Koch
iaB
assi
a sc
opar
iaC
heno
podi
acea
eF
IX
XX
XD
istu
rbed
soi
l of r
oads
ides
, pas
ture
s, ra
ngel
and,
farm
yard
s,
culti
vate
d fie
lds,
tole
rant
of s
alin
e so
il La
brad
or te
aLe
dum
gla
ndul
osum
Eric
acea
eS
NX
XX
XM
oist
to w
et fo
rest
s an
d m
eado
ws;
val
leys
to s
ubal
pine
Lam
bsqu
arte
rsC
heno
podi
um a
lbum
Che
nopo
diac
eae
FN
, IX
XX
XX
Dis
turb
ed s
oils
of r
oads
ides
, fiel
ds, r
ange
land
, pas
ture
s
Lark
spur
, low
Del
phin
ium
bic
olor
, D.
nutta
llian
um,
D. g
eyer
i, an
d ot
hers
Ran
uncu
lace
aeF
NX
XX
XG
rass
land
s, s
ageb
rush
ste
ppe,
ope
n fo
rest
or w
oodl
and,
ro
cky
ridge
s
Lark
spur
, tal
lD
elph
iniu
m b
arbe
yi,
D. o
ccid
enta
le, D
gl
aucu
m, a
nd o
ther
s
Ran
uncu
lace
aeF
NX
XX
Dee
p, m
oist
soi
ls, m
ount
ain
mea
dow
s, a
spen
sta
nds,
alo
ng
stre
ams
or a
roun
d se
eps
and
sprin
gs
1 G =
gra
ss /
gram
inoi
d / g
rass
-like
, F =
forb
/ br
oadl
eaf p
lant
, S =
shr
ub, T
= tr
ee
2 N
= N
ativ
e, I
= In
trodu
ced
to M
onta
na a
nd W
yom
ing
3 Sta
te-li
sted
nox
ious
wee
d in
Mon
tana
(M),
Wyo
min
g (W
), or
bot
h (B
).
Tabl
e 3,
(con
t.)
- 37 -
1 G =
gra
ss /
gram
inoi
d / g
rass
-like
, F =
forb
/ br
oadl
eaf p
lant
, S =
shr
ub, T
= tr
ee
2 N
= N
ativ
e, I
= In
trodu
ced
to M
onta
na a
nd W
yom
ing
3 Sta
te-li
sted
nox
ious
wee
d in
Mon
tana
(M),
Wyo
min
g (W
), or
bot
h (B
).
Plan
t Spe
cies
Scie
ntifi
c N
ame(
s)Pl
ant F
amily
Lifeform1
Native2
Noxious3
Hab
itat
Hab
itat D
escr
iptio
n
Mountains
Foothills
Shrubland
Plains
Valleys
Wet Areas
Cropland
Disturbed
Laur
elK
alm
ia p
olifo
lia,
K. m
icro
phyl
laEr
icac
eae
SN
XX
Moi
st m
eado
ws
and
fore
sts,
bog
s, a
roun
d la
kes;
up
to
alpi
ne
Leaf
y sp
urge
Eup
horb
ia e
sula
Euph
orbi
acea
eF
IB
XX
XX
XX
Gra
ssla
nds,
mea
dow
s, w
oodl
ands
, rip
aria
n fo
rest
, pas
ture
s an
d pr
airie
sLo
cow
eed
Oxy
tropi
s se
ricea
, O
. lam
bert
ii, a
nd
othe
rs
Faba
ceae
FN
XX
XX
Gra
ssla
nds
with
wel
l-dra
ined
soi
l, ra
ngel
and,
sag
ebru
sh
step
pe, d
ry w
oodl
ands
, pas
ture
s, a
nd e
xpos
ed ri
dges
at a
ll el
evat
ions
Lu
pine
Lupi
nus
seric
eus,
L.
cau
datu
s,
L. le
ucop
hyllu
s,
L. a
rgen
teus
, L.
pla
ttens
is,
L. p
olyp
hyllu
s, L
. pu
sillu
s, a
nd o
ther
s
Faba
ceae
FN
XX
XX
XX
Man
y sp
ecie
s of
lupi
ne in
MT
and
WY;
not
all
are
pois
onou
s; S
peci
es li
sted
are
mos
t com
mon
ly c
ited
for
toxi
ns; v
arie
d ha
bita
t fro
m d
ry, s
andy
soi
l of g
rass
land
s,
sage
brus
h st
eppe
, stre
amba
nks,
moi
st m
eado
ws,
dry
, ope
n fo
rest
, woo
dlan
ds; a
ll el
evat
ions
Mal
low
, com
mon
Mal
va n
egle
cta
Mal
vace
aeF
IX
XX
Dis
turb
ed p
astu
res,
bar
nyar
ds, w
aste
are
asM
atrim
ony
vine
Lyci
um b
arba
rum
Sola
nace
aeS
IX
XX
Fiel
ds, r
oads
ides
, far
mst
eads
, was
te a
reas
Milk
vetc
hA
stra
galu
s sp
p.
(not
A. c
icer
)Fa
bace
aeF
NX
XX
XX
XM
any
spec
ies
in M
T an
d W
Y va
ry in
hab
itat a
nd to
xici
ty;
Ston
y, m
oist
soi
l of g
rass
land
s, s
ageb
rush
ste
ppe,
alk
alin
e m
eado
ws,
gra
vel b
ars,
thic
kets
, nea
r wet
land
s or
stre
ams,
op
en fo
rest
, lim
esto
ne-d
eriv
ed s
oil,
clay
soi
l; al
l ele
vatio
nsM
ilkw
eed
Asc
lepi
as s
pp.
Ascl
epia
dace
aeF
NX
XX
XX
Mea
dow
s, s
tream
bank
s, g
rass
land
s, b
adla
nds,
pin
e w
oodl
ands
, fiel
ds, r
oads
ides
, ditc
hes,
mar
shes
, pra
irie
poth
oles
Mill
etP
enni
setu
m g
lauc
umPo
acea
eG
IX
Cul
tivat
edM
onks
hood
Aco
nitu
m c
olum
bian
umR
anun
cula
ceae
FN
XX
XM
oist
to w
et m
eado
ws,
ope
n m
oist
fore
st, a
long
stre
ams;
up
to s
ubal
pine
Mou
ntai
n m
ahog
any,
cur
l-le
af a
nd tr
ue
Cer
coca
rpus
ledi
foliu
s,
C. m
onta
nus
Ros
acea
eS
NX
XX
Ston
y sl
opes
, cliff
s, ro
ck o
utcr
ops,
on
limes
tone
or
sand
ston
e, o
pen
pine
fore
st
Nig
htsh
ade
Sol
anum
spp
.So
lana
ceae
FN
, IX
XX
XX
Rip
aria
n fo
rest
s, w
oodl
ands
, thi
cket
s, g
rass
land
s, p
astu
res,
al
ong
stre
ams,
dis
turb
ed s
oils
, ditc
hes,
road
side
s, fe
nces
, fa
rmya
rds,
cul
tivat
ed fi
eld
edge
Oni
onA
llium
spp
.Li
liace
aeF
NX
XX
XX
XM
any
spec
ies
in M
T an
d W
Y th
at v
ary
in h
abita
t; gr
assl
ands
, sag
ebru
sh s
tepp
e, o
pen
fore
st, m
eado
ws,
w
oodl
ands
, thi
cket
s, ri
paria
n ar
eas,
rock
out
crop
s; a
ll el
evat
ions
Tabl
e 3,
(con
t.)
- 38 -
1 G =
gra
ss /
gram
inoi
d / g
rass
-like
, F =
forb
/ br
oadl
eaf p
lant
, S =
shr
ub, T
= tr
ee
2 N
= N
ativ
e, I
= In
trodu
ced
to M
onta
na a
nd W
yom
ing
3 Sta
te-li
sted
nox
ious
wee
d in
Mon
tana
(M),
Wyo
min
g (W
), or
bot
h (B
).
Plan
t Spe
cies
Scie
ntifi
c N
ame(
s)Pl
ant F
amily
Lifeform1
Native2
Noxious3
Hab
itat
Hab
itat D
escr
iptio
n
Mountains
Foothills
Shrubland
Plains
Valleys
Wet Areas
Cropland
Disturbed
Pens
tem
onP
enst
emon
spp
.Sc
roph
ular
iace
aeF
NX
XX
XX
XSa
ndy,
rock
y or
wel
l-dra
ined
soi
l; gr
assl
ands
, sag
ebru
sh
step
pe, r
ock
outc
rops
, ope
n fo
rest
and
woo
dlan
ds,
road
cuts
, mea
dow
s; a
ll el
evat
ions
Phea
sant
’s e
yeA
doni
s ae
stiv
alis
Ran
uncu
lace
aeF
IX
XEs
cape
d or
nam
enta
l pla
nt, w
eed
in c
ultiv
ated
fiel
ds,
past
ures
, roa
dsid
esPi
ne, p
onde
rosa
Pin
us p
onde
rosa
Pina
ceae
TN
XX
XX
Drie
r for
ests
, roc
ky e
xpos
ures
ass
ocia
ted
with
gra
ssla
nds
Prin
cesp
lum
eS
tanl
eya
pinn
ata
Bras
sica
ceae
FN
XX
XX
Cla
y so
il an
d dr
y, s
elen
ium
-ric
h so
il on
ope
n sl
opes
, bar
ren
hills
and
flat
s, s
tream
bank
s, b
adla
nds
Punc
ture
vine
Trib
ulus
terr
estri
sZy
goph
ylla
ceae
FI
XX
XD
ry, s
andy
or g
rave
lly s
oil o
f stre
amba
nks,
pas
ture
s,
road
side
s, w
aste
are
asPu
rsla
neP
ortu
laca
ole
race
aPo
rtula
cace
aeF
IX
XR
ich
dist
urbe
d so
il of
farm
yard
s, w
aste
are
as, c
ultiv
ated
fie
lds
Red
root
pig
wee
dA
mar
anth
us re
trofle
xus
Che
nopo
diac
eae
FN
XX
XX
XC
ultiv
ated
fiel
ds, r
oads
ides
, stre
amba
nks,
was
te a
reas
Ree
d ca
nary
gras
sP
hala
ris a
rund
inac
eaPo
acea
eG
IX
XX
Stre
amba
nks,
ditc
h ba
nks,
wet
land
s, m
ostly
at l
ower
to
mid
dle
elev
atio
ns.
Rye
gras
s,
pere
nnia
lLo
lium
per
enne
Poac
eae
GI
XD
istu
rbed
site
s, ro
adsi
des,
trai
l sid
es, a
nd n
ewly
pla
nted
la
wns
Sage
, lan
cele
afS
alvi
a re
flexa
Lam
iace
aeF
NX
XX
XD
istu
rbed
are
as, r
oads
ides
, fiel
ds, p
astu
res,
and
was
te
area
sSa
ge, s
and
and
fring
ed s
age
Arte
mis
ia fi
lifol
ia,
A. f
rigid
a As
tera
ceae
SN
XX
XM
any
spec
ies
in M
T an
d W
Y th
at v
ary
in h
abita
t; St
ony
or s
andy
soi
ls o
f gra
ssla
nds,
sag
ebru
sh s
tepp
e, o
pen
mea
dow
s, c
onife
rous
woo
dlan
dsSa
gebr
ush,
big
Arte
mis
ia tr
iden
tata
Aste
race
aeS
NX
XX
XX
XD
eep
soils
of s
ageb
rush
ste
ppe,
ste
ep o
pen
slop
es, d
ry
plai
ns a
nd h
illsi
des;
val
leys
to s
ubal
pine
Sa
gew
ort,
gree
n an
d w
hite
Arte
mis
ia d
racu
ncul
us,
A. l
udov
icia
naAs
tera
ceae
FN
XX
XX
XX
XG
rass
land
s, m
eado
ws,
sag
ebru
sh s
tepp
e, s
tream
bank
s,
road
side
s, ta
lus
slop
esSa
ltbus
hA
tripl
ex s
pp.
Che
nopo
diac
eae
SN
XX
XX
XU
sual
ly o
n al
kalin
e or
sal
ine
soil
of s
ageb
rush
ste
ppe,
gr
assl
ands
, bad
land
sSc
otch
bro
omC
ytis
us s
copa
rius
Faba
ceae
SI
MX
XM
oist
road
side
sSc
ram
bled
egg
sC
oryd
alis
aur
eaFu
mar
iace
aeF
NX
XX
XX
Moi
st, o
pen
fore
sts,
dis
turb
ed a
reas
; val
leys
to s
ubal
pine
Serv
iceb
erry
Am
elan
chie
r aln
ifolia
Ros
acea
eS
NX
XX
XX
XM
oist
to d
ry fo
rest
s, g
rass
land
s, m
eado
ws,
woo
dlan
ds,
stre
amba
nks,
ava
lanc
he s
lope
s; v
alle
ys to
low
er s
ubal
pine
Snak
ewee
dG
utie
rrez
ia s
arot
hrae
Aste
race
aeF
NX
XX
XX
Sage
brus
h st
eppe
, gra
ssla
nds,
juni
per w
oodl
ands
, ba
dlan
ds, p
astu
res;
val
leys
to s
ubal
pine
Tabl
e 3,
(con
t.)
- 39 -
1 G =
gra
ss /
gram
inoi
d / g
rass
-like
, F =
forb
/ br
oadl
eaf p
lant
, S =
shr
ub, T
= tr
ee
2 N
= N
ativ
e, I
= In
trodu
ced
to M
onta
na a
nd W
yom
ing
3 Sta
te-li
sted
nox
ious
wee
d in
Mon
tana
(M),
Wyo
min
g (W
), or
bot
h (B
).
Plan
t Spe
cies
Scie
ntifi
c N
ame(
s)Pl
ant F
amily
Lifeform1
Native2
Noxious3
Hab
itat
Hab
itat D
escr
iptio
n
Mountains
Foothills
Shrubland
Plains
Valleys
Wet Areas
Cropland
Disturbed
Snee
zew
eed
Hym
enox
ys h
oope
sii
Aste
race
aeF
NX
Moi
st s
lope
s an
d w
ell-d
rain
ed m
eado
ws;
up
to s
ubal
pine
Sorg
hum
s, fo
rage
, gr
ain,
sor
ghum
-su
dang
rass
, su
dang
rass
Sor
ghum
bic
olor
, S
. x d
rum
mon
dii,
S. b
icol
or v
ar.
suda
nene
se
Poac
eae
GI
XC
ultiv
ated
, rar
ely
esca
ping
Sorr
elO
xalis
spp
.O
xalid
acea
eF
N, I
XX
XX
XO
pen
fore
sts,
pra
iries
, fiel
ds, s
tream
bank
s, w
aste
are
as
St. J
ohns
wor
tH
yper
icum
per
fora
tum
Clu
siac
eae
FI
BX
XX
XG
rass
land
, ope
n fo
rest
, pas
ture
s, m
eado
ws,
road
side
s,
dist
urbe
d ar
eas
Suck
leya
, poi
son
Suc
kley
a su
ckle
yana
Che
nopo
diac
eae
FN
XX
XSp
arse
ly v
eget
ated
soi
l of r
eced
ing
lake
s an
d po
nds
or fl
ood
area
s, c
ultiv
ated
fiel
dsSu
nflow
er
Hel
iant
hus
spp.
Aste
race
aeF
N, I
XX
XX
XD
istu
rbed
soi
l of fi
elds
, gra
ssla
nds,
rang
elan
d, s
tream
bank
s,
wet
mea
dow
s, th
icke
ts, r
oads
ides
, cul
tivat
ed fi
elds
Sw
eetc
love
r, ye
llow
and
whi
teM
elilo
tus
offici
nalis
Faba
ceae
FI
XX
XX
XR
oads
ides
, fiel
ds, s
tream
bank
s, g
rass
land
s, ra
ngel
and,
op
en s
lope
s in
bad
land
sS
wee
tpea
Lath
yrus
spp
.Fa
bace
aeF
NX
XX
XX
Roa
dsid
es, fi
elds
, thi
cket
s, m
eado
ws,
moi
st a
reas
, ope
n as
pen
or p
ine
fore
stTa
nsy,
com
mon
Tana
cetu
m v
ulga
reAs
tera
ceae
FI
BX
XX
XM
oist
dis
turb
ed m
eado
ws,
alo
ng s
tream
s an
d di
tche
s Ta
nsy
mus
tard
Des
cura
inia
pin
nata
Bras
sica
ceae
FN
XX
XX
XX
Gra
ssla
nds,
cul
tivat
ed fi
elds
, roa
dsid
es, w
aste
are
asTa
nsy
ragw
ort
Sen
ecio
jaco
baea
Aste
race
aeF
IM
XX
XD
istu
rbed
soi
l of o
pen
fore
st, m
eado
ws,
pas
ture
s, o
ften
asso
ciat
ed w
ith ti
mbe
r har
vest
or fi
reTe
ffE
ragr
ostis
tef
Poac
eae
GI
XC
ultiv
ated
, rar
ely
esca
ping
This
tle, C
anad
aC
irsiu
m a
rven
seAs
tera
ceae
FI
BX
XX
XX
XX
Moi
st d
istu
rbed
soi
ls o
f fiel
ds, m
eado
ws,
thic
kets
, roa
dsid
es,
woo
dlan
ds, o
pen
fore
st, s
tream
bank
s, w
etla
nds
This
tle, R
ussi
anS
also
la tr
agus
Aste
race
aeF
IX
XX
XD
ry d
istu
rbed
soi
ls o
f roa
dsid
es, c
ultiv
ated
fiel
ds, d
ry la
ke
beds
, was
te a
reas
Toba
cco,
coy
ote
Nic
otia
na a
ttenu
ata
Sola
nace
aeF
NX
XX
XX
Sand
y or
gra
velly
soi
l of s
tream
bank
s, h
ills,
railr
oad
right
-of-
way
, was
te a
reas
Vetc
h, h
airy
Vic
ia v
illos
aFa
bace
aeF
IX
XX
Roa
dsid
es, c
ultiv
ated
fiel
ds, g
rass
land
sW
hite
top
Car
daria
dra
baBr
assi
cace
aeF
IB
XX
XX
XX
XX
Fiel
ds, r
oads
ides
, stre
amba
nks
Yello
w s
tarth
istle
C
enta
urea
sol
stiti
alis
Aste
race
aeF
IB
XX
XX
XFi
elds
, gra
ssla
nds,
road
side
s, d
istu
rbed
are
asYe
wTa
xus
brev
ifolia
Taxa
ceae
SN
XX
XX
Wet
fore
st, h
umid
env
ironm
ents
, usu
ally
on
acid
soi
ls
Tabl
e 3,
(con
t.)
Resources and ReferencesCarlson, M. and B. Anderson. 2013. Cyanide Poisoning, University of Nebraska Lincoln Extension
NebGuide G2184, Lincoln, NE. Available at: http://extensionpubs.unl.edu/
Cornell University. 2007. Brown midrib sorghum sudangrass: successfully growing a high energy grass for dairy cows. Cornell University Cooperative Extension, Agronomy Fact Sheet Series 14, Ithaca, NY. Available at: http://nmsp.cals.cornell.edu/publications/factsheets/factsheet14.pdf
Dorn, R.D. 2001. Vascular Plants of Wyoming. Mountain West Publishing, Cheyenne, WY.
Drewnoski, M., B. Anderson, P. Kononoff, and B. Reynolds. 2019. Nitrates in Livestock Feeding. University of Nebraska Extension NebGuide G1779, Lincoln, NE. Available at: http://extensionpubs.unl.edu/
Forero, L., G. Nadar, A. Craigmill, J. DiTomaso, B. Puschner, and J. Maas. 2010. Livestock-Poisoning Plants of California. University of California Agricultural and Natural Resources Publication 8398, Davis, CA. Available at: https://anrcatalog.ucanr.edu/
Gadberry, S. and J. Jennings. 2016. Nitrate Poisoning in Cattle. University of Arkansas Division of Agriculture Research and Extension, FSA3024, Little Rock, AR. Available at: https://www.uaex.edu/publications/
Glunk, E., K. Olson-Rutz, M. King, D. Wichman, and C. Jones. 2015. Nitrate Toxicity of Montana Forages. Montana State University Extension MontGuide MT200205AG, Bozeman, MT. Available at: https://store.msuextension.org/
Green, B.T., K.D. Welch, J.A. Pfister, C.G. Chitko-McKown, D.R. Gardner, and K.E. Panter. 2014. Mitigation of larkspur poisoning on rangelands through the selection of cattle. Rangelands 36(1):10-15.
Green, B.T., D.R. Gardner, D. Cook, J.A. Pfister, K.D. Welch, and J.W. Keele. 2018. Age-dependent intoxication by larkspur (Delphinium) in Angus steers. Toxicon 152:57-59.
James, L.F., D.B. Nielsen, and K.E. Panter. 1992. Impact of poisonous plant on the livestock industry. Journal of Range Management 45(1):3-8.
Knight, A.P. and R.G. Walter. 2001. A Guide to Plant Poisoning of Animals in North America. International Veterinary Information Service, Ithaca, NY.
Leininger, W., J. Taylor, and C. Wambolt. 1977. Poisonous Range Plants of Montana. Montana State University Cooperative Extension Service Bulletin 348. Montana State University, Bozeman, MT.
Lesica, P. 2012. Manual of Montana Vascular Plants. Brit Press, Fort Worth, TX.
Majak, W., B. Brooke, and R. Ogilvie. 2008. Stock-poisoning Plants of Western Canada. Government of Canada, Agriculture Canada.
Montana Department of Agriculture. 2019. Montana state-listed noxious weeds. Montana Department of Agriculture, Noxious Weeds Program, Helena, MT. Available at: https://agr.mt.gov/Weeds
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Panter, K., M.H. Ralphs, J. Pfister, D. Gardner, B. Stegelmeier, S. Lee, K. Welch, B. Green, T. Davis, and D. Cook. 2011. Plants Poisonous to Livestock in the Western States. U.S. Department of Agriculture, Agricultural Research Service, Agriculture Bulletin 415, Logan, UT. Available at: https://www.ars.usda.gov/is/np/PoisonousPlants/PoisonousPlants.pdf
Pokorny, M. and J. Mangold. 2020. Montana’s Noxious Weeds. Montana State University Extension Service EB0159, Bozeman, MT. Available at: https://store.msuextension.org/
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Smith, M., J. Waggoner, and S. Sims. 2010. Larkspur: Managing grazing to avoid poisoning cattle. University of Wyoming Range Facts MP-111.13, Laramie, WY. Available at: http://www.wyoextension.org/publications/
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Stubbendieck, J., M. Carlson, C. Dunn, B. Anderson, and D. Redfearn. 2018. Nebraska Plants Toxic to Livestock, Including Bloat-Causing Plants, Rangeland, Pastureland, and Cropland. University of Nebraska Extension EC3037, Lincoln, NE. Available at: https://extensionpubs.unl.edu/
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Whitson, T., L. Burrill, S. Dewey, D. Cudney, B. Nelson, R. Lee, and R. Parker. 2002. Weeds of the West. The Western Society of Weed Science, Newark, CA.
Wyoming Department of Agriculture. 2018. Wyoming state designated noxious weeds, Wyoming Department of Agriculture, Weed and Pest Program, Cheyenne, WY. Available at: http://wyagric.state.wy.us/divisions/ts/sections-a-programs/weed-a-pest
- 42 -
GlossaryAcute poisoning – Adverse effects from a substance
resulting either from a single exposure or from multiple exposures in a short period of time.
Alkaloid – Naturally occurring basic, organic, nitrogenous compounds.
Anemia – Deficiency of red blood cells or hemoglobin in the blood.
Ataxia – Loss of full control of bodily movements.
Bloat – A disease in livestock characterized by an accumulation of gas in the stomach. To make or become swollen with fluid or gas.
Cannabinoids –Psychoactive chemicals, obtained from plants of the Cannabis genus, that have toxic effects on the nervous system.
Chronic poisoning – Adverse effects from a substance result of a long-term exposure when toxins accumulate over time and damage is permanent.
Cicutoxin – An unsaturated alcohol which acts on the central nervous stimulant.
Colic – Severe, often fluctuating pain in the abdomen caused by intestinal gas or obstruction in the intestines.
Congenital – Existing at birth, but not hereditary.
Cotyledon – An embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed.
Cyanosis – Blue coloring of the lining of the mouth.
Cystitis – Inflammation of the bladder.
Dicoumarol – Toxic product synthesized from coumarin in moldy sweetclover.
DDMP – A complex compound (2,3-dihydro-3,5-dihydroxy-6-(H) -pyran-4-) that inhibits the dopamine transporter system of the brain affecting cranial nerves.
Edema – Excess of watery fluid collecting in the cavities or tissues of the body.
Endophyte – An organism, often fungi or bacteria, living within a plant between living plant cells. The relationship with the plant varies from symbiotic to bordering on pathogenic.
Fetal mummification – Shriveling or shrinkage of fetus by absorbing all fluid of fetus and uterus.
Forb – A broad-leaved herbaceous plant.
Furanocoumarins – Organic chemical compounds associated with photosensitivity through ingestion and direct contact with the skin. When the phytochemicals enter the nucleus of epithelial cells and form a bond with the DNA, it causes the cells to die resulting in the skin being unable to protect itself from sunlight.
Gallic Acid – A substance, occurring in a free state or combined as gallotannin, causing skin and mucosal irritation.
Glycoside – Any group of organic compounds occurring within plants that produce sugars and related substances upon hydrolysis.
Hemolysis – Rupture or destruction of red blood cells.
Hepatic – Relating to, affecting, associated with, supplying or draining the liver.
Hepatopathy – An abnormal or diseased state of the liver.
Hydrogen cyanide (HCN) – (also known as prussic acid) Extremely toxic, volatile, rapidly acting poison that inactivates cellular respiration by depriving cells of oxygen.
Hypericin – A phototoxin contained in pigment glands that fluoresce in the presence of sunlight and causes acute inflammation and necrosis of cells of the skin capillaries. Only white or unpigmented skin areas are affected. These areas itch and become red, swollen, and sore, and the skin may peel or come off in large sheets (photosensitization).
Hypertonic muscle – Too much muscle tone so that areas are stiff and difficult to move.
Irisin – A toxin chemical found in Iris rhizomes which can cause abdominal pain, burning sensation of the mouth and throat, and vomiting if ingested and mild skin irritation upon skin exposure.
Integumentary – The outer protective layer of an animal or plant. The integumentary system comprises the skin and its appendages (hair, hooves) which protect the body from damage.
Isocupressic acid –A diterpene acid that interferes with blood flow to the uterus and can induce abortion in cattle in the last three months of pregnancy.
Jaundice – Yellowing of the skin or whites of the eyes, caused by obstruction of the bile duct, liver disease, or excessive breakdown of red blood cells.
Laminitis – Inflammation of the sensitive layers of tissue inside the hoof in horses and other animals. It can cause extreme lameness.
- 43 -
Monoterpene – A class of terpenes produced in plants that often have a strong odor and may protect the plants.
Mycotoxin – A toxin produced by a fungus. Major classes of mycotoxins include aflatoxins, trichothecenes, fumonisins, zearalenone, ochratoxin, and ergot alkaloids.
Neurotoxic diterpenoid – Toxins, including andromedotoxin and grayanotoxin, present throughout the plant. Symptoms of poisoning include vomiting, depression, hypotension, irregular heartbeat, colic, convulsions, inability to coordinate voluntary muscles and recumbency.
Nitrotoxin – Neurotoxin compounds contained in some milkvetch species that are poisonous to cattle, sheep and horses with cattle being the most commonly affected. Symptoms of nitrotoxin poisoning include weakness (staggered gait, clicking of hooves while walking), ataxia, muscle tremors, depression, recumbency and death.
Oxalate – Poisonous salt of dibasic acid.
Petechial hemorrhage – Tiny pinpoint red mark caused when the body is deprived of oxygen.
Photophobia – Extreme sensitivity to light.
Photosensitivity – Light sensitivity causing abnormal skin reaction to direct sunlight exposure.
Photosensitization – Sensitization of the skin to light. The development of an abnormal capacity to react to sunlight typically by edematous swelling and dermatitis.
Plains – Plains and valleys are the lowest elevation habitat in a given area. Plains are influenced by the Great Plains which generally have more growing season precipitation than valleys.
Poison – A substance that can cause the illness or death of a living organism when introduced or absorbed. Synonym: toxin; Adjective: poisonous.
Prostration – Lying stretched out on the ground.
Prussic acid – (also known as hydrogen cyanide) Extremely toxic, volatile, rapidly acting poison that inactivates cellular respiration by depriving cells of oxygen.
Rectal prolapse – Rectal walls have prolapsed to a degree where they protrude out the anus and are visible outside the body.
Recumbency – Laying down, unable to walk or remain standing.
Renal – Relating to the kidneys.
Rumen stasis – Collapse of ruminal function, cessation of normal rhythmic contractions for more than two minutes.
Selenium – An essential trace nutrient for animals. In certain plants it accumulates to levels that are toxic to livestock when those plants are growing in selenium-rich soils.
Sesquiterpene lactone – A terpene (sesquiterpene) containing a lactone ring. It can cause allergenic (irritate eyes, nose, gastrointestinal tracts) or neurotoxic (necrosis or death of neural tissue) effects.
Sulfate – A salt or ester of sulfuric acid. Animals consuming plants with high levels of sulfate will reduce sulfate to hydrogen sulfide in the rumen resulting in degenerative changes in the brain causing depression, blindness or death.
Tannic acid – A form of tannin that is a weak acid and a type of polyphenol found in some plants.
Tannin – A bitter-tasting organic substance present in some galls, barks, and other plant tissue.
Teratogen – A chemical or agent (e.g. alkaloid) which crosses the placenta and interferes with embryo or fetus development producing an embryonic or fetal defect. Extent of the defect depends on the teratogen and the stage of development.
Tetany – A stimulated neuromuscular activity caused by deficiencies of calcium and/or magnesium.
Tetradymol – A sesquiterpene that is a liver toxin.
Thiaminase – An enzyme that produces thiamin (vitamin B1) deficiency in livestock by destroying ingested thiamine after ingestion and reducing thiamine availability. Thiamin deficiency results in retinal degeneration, blindness, depression, weight loss, and hemorrhaging syndrome.
Thujone – A ketone and monoterpene, which occurs naturally, has a menthol odor, and may cause effects resembling epilepsy.
Toxin – A substance produced by a living organism that is poisonous to another living organism. Synonym: poison; Adjective: toxic.
Valley – Valley and plains are the lowest elevation habitats in a given area. Valleys are generally in mountainous areas and rain-shadows.