PREPARING A FLOCK FOR BREEDING

A brief guide for shepherds covering:• Selecting stock• Methods to prepare a flock• Role of disease prevention

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Criteria used in selecting stock for breeding.

Breed

ewes

Determining what breed has the qualities you need is necessary for success, depending on what your flock produces will greatly effect this. If you run a pedigree herd obviously you don’t want to be diluting your gene pool with different breeds. If you are producing lambs for slaughter it would be recommended to use crossbred ewes (e.g. north country mule) As they tend to have good characteristics for producing slaughter lambs e.g. good mothering, decent conformation and milkiness.

Rams

The same would apply to rams when selecting for a pedigree flock, however with slaughter lamb production a ram with a higher conformation to be a terminal sire is usually desired as the good conformation of the ram will lead to a crop of lambs with suitable conformation for market needs.

Why is this important?

Though breed doesn’t necessarily mean everything, as the animals within a breed can vary as much as the breeds themselves, breeds do tend to conform to general characteristics. Using a breed that’s not suitable to what you need is just wasting money as you’ll have produce not wanted by the market which will lead to penalisation and your breeds may not be suitable for your system or make the most of it (e.g. putting a hill breed that can cope with poor grazing would be wasted putting it on more valuable lowland grazing.)

Conformation

This is the ability of the animal to put on muscle tissue, large lean carcasses are generally what’s wanted by the UK market so animals with better conformation are usually more desirable. However larger muscled animals tend to have problems associated with this such as difficulty birthing, lack of milk etc… (Breeds like Texal’s are notoriously difficult to lamb). What a slaughter lamb producer would be looking for in a good crossbred ewe will tend to be good conformation, but not to the extent that there are excessive lambing difficulties like breeds on the extreme side of the conformation scale. Rams on the other hand tend to be bred to be as muscular as possible such as the Suffolk to be used as terminal sires on crossbreds (e.g. north country mule).

Why is this important?

If your producing slaughter lambs this is really important because at the end of the day conformation equals how much muscle the animal puts on and muscle is what people are purchasing. If you have poor conformation you won’t produce muscular carcasses which will lose you money. If you are a breed this is also important as conformation is a trait that is really looked for, some farmers will look past some genetic issues if it has superb conformation e.g. Entropion (this is however a very poor breeding and business practice).

Suitability for purpose

You need to know what you are producing and the ewe has to be suited to that.

Performance records

EBV’s or estimated breeding values have become a common and effective way to grade your livestock based on performance and helps show the breeding potential of an animal. This system was started by signet. This sort of grading only measures the ram and the lambs performance.

(Above). This is the sort of information that the EBV measures. When you see a sheep’s EBV it can be shown in a chart form that will show you how that animal compares to the national average. The measured traits are important for productivity such as maternal ability which is measured by the lambs weight gain by 8 weeks.

The index at the bottom shows the overall effectiveness of the animal this can be used to determine its value but it is best to look at each trait individually to see if it suits your needs.

Why is this important?

This is important because traditionally sheep’s traits were selected visually such as looking at conformation, fleece quality etc… but the EBV allows the shepherd purchasing to see essentially the majority of its production history easily, thing that can’t be visually determined before purchase such as maternity levels and prolificacy can now be viewed saving unexpected surprises.

It does however need to be taken into account that the lamb will inherit 50% of the genes and therefore the combined values of traits the progeny receive will consist of the ewes and rams score halved and added together as shown in this example.

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Scrapie genotyping

Scrapie is essentially the sheep equivalent of BSE (Bovine spongiform encephalopathy) or more commonly known as mad cow disease. The disease if fatal and can be transmitted from flock to flock Early signs include subtle changes in behavior or temperament. These changes may be followed by scratching and rubbing against fixed objects, apparently to relieve itching. Other signs are loss of coordination, weight loss despite retention of appetite, biting of feet and limbs, lip smacking, and gait abnormalities, including high-stepping of the forelegs, hopping like a rabbit, and swaying of the back end. Though it hasn’t been shown to spread to humans all animals with the disease need to be culled to avoid spreading it, this can incur huge losses.

Some sheep are significantly more genetically susceptible to the disease than others this affected by the amino acid sequence of the sheep’s prion protein.

What is genotyping?

It’s a DNA test for genetic resilience and can be tested for by taking a blood sample and sending it to be genotyped, this will tell you which sheep have more susceptible genes. This service is provided by many businesses but it can cost quite a lot with the test costing from around £14 per animal. This does however mean by introducing scrapie resistant rams into the flock over time the flock will be significantly more resistant.

Why is this important?

Though the disease has died down with only 23 cases in the UK in 2013 there is still a large potential for another outbreak to happen due to more and more farms getting complacent with genotyping Scrapie caused considerable loss of stock and led to some businesses being ruined.

Methods of preparing a flock for breeding

Condition scoring.This is a method of visually and physically checking the body condition of a sheep. This is done by feeling the spine, the rear ribs and the dock for the bones, if it’s very boney it’s too skinny if the bones can’t be felt at all its too fat the scale ranges from 1-5 (1 being very skinny 5 being far to fat).it is usually done at specific points in the breeding schedule to make sure they are suitably well fed and healthy.

Recommended points and eblex recommended scores:

If ewes aren’t at the ideal condition score at the current point early condition scoring allows you to make changes,

• Segregate ewes post weaning into three groups–fat (>3.5)*, fit (3–3.5)* and thin (2.5 or less)*.

• Identify pasture that will enable ewes to reach optimum score (3–3.5)* by tupping.

• Realise that to gain 1 BCS, a ewe needs access to unrestricted grazing for 6-8 weeks

Rams

Rams body condition score should be between 3.5 and 4.0 (1 = very thin and 5 = very fat) as tupping starts. Good condition is vital as 15% of bodyweight can be lost in six weeks of tupping.

Why is this necessary?

Regular condition scoring is needed so you can spot any problems in terms of condition score and rectifiy it before it becomes an issue e.g. if the ram is not a suitable condition level before tupping it can have decreases in sperm count/fertility and is also

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likely to not have enough energy to get around the flock. Or in a ewes case it might not have the nutrients to have a litter and might abort.

Checking feet

Lameness in sheep can lead to great discomfort in the animal and also drops in productivity, this is due to the fact that when in pain animals are generally less likely to carry out normal behaviors such as feeding etc… meaning they can lose condition and potentially litters therefore Annual foot inspection is to be recommended but trimming should only be undertaken in a minority of cases. The purpose of trimming is to remove overgrown horn, leaving sufficient wall to take the weight of the sheep. The corium should not be exposed nor should bleeding be an outcome. While foot trimming is still essential to correctly locate and drain a foot abscess, recent research work has shown that foot trimming is counter-productive in cases of footrot.

Udders

Checking udders is necessary as the udders will provide the best food source for your crop of lambs early on it is recommended that you check them and deal with any issues e.g. mastitis as that can lead to the death of the lamb and potentially the ewe if left untreated.

It is a good idea if possible to check the ewes udders pre breeding and after weaning. If this isn’t done your last time to check is as soon as they have been penned up before the lamb has drunk, checking the udder has the correct amount teats and no lumps. you might be able to get away with small lumps which are far away from the teat but this still carries a large risk and it is recommended that these ewes are either treated with an intramammery injection of a combination of penicillin, dihydrostreptomycin, dexamethasone and an antihistamine or culled. In most cases the sheep will lose the teat even with treatment.

Also it is advisable to observe for summer mastitis from turning out till after weaning. Preventative measures such as fly repellent and teat protection can also help.

Checking teeth

Checking teeth or mouthing is needed to find out two things. Firstly the age and secondly the condition of its teeth. This can be done at any time the ewes need to go through the race but a good example might be before turning out when drenching or when giving the colostridial booster.

Related husbandry tasks

Checking teeth is necessary so you can know which will be able to cope with difficult feed such as stubble turnips and so that ewes and rams with badly worn teeth or “gummers” can be culled as they won’t be able to eat well and their condition score will decrease.

Checking rams

rams need to be healthy and in suitable fitness level to be successful during tupping, treating rams as anything less than vital all year round is a mistake that can have significant weight to it as fertility and the amount of ewes they can get to can fall drastically if not given the right care.

When checking rams pre-tupping its good to remember The four Ts: Teeth, Toes, Tone and Testicles

Teeth- if the teeth of the ram get to worn or to many are lost he won’t be able to get the nutrition he needs to be successful and will need to be culled. You should also look to see if they over cut or undercut, as this will also affect his performance and may be inherited.

Toes- a lame ram will find tupping extremely difficult and wearing if not checked. Feet may need trimming and foot bathing to prevent or treat problems. Check older rams for arthritis. You should also look at how the ram moves around to check for issues.

Tone- the rams condition score needs to be between 3.5-4 at the start of tupping, as the ram will exert a huge amount of energy and will lose around 15% body weight in 6 weeks of tupping due to him running on his reserves as they tend not to have enough time to feed.

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Testicles – should be large and as firm as a flexed bicep looking for equally sized ones aswell. Large, firm testicles produce 80% more semen each day than medium-sized, soft ones. If more semen is produced, he is more fertile and fewer rams will be needed to serve the flock.

Checking rams sexual organs

For a more detailed check-up you could also examine these areas.

Pizzle The pizzle or the penis sheath needs to be checked pre tupping for sores or infections such as pizzle rot as that can cause infertility. You also need to check that it can extrude its penis without issue.

EpididymisThe Epididymis is the bottom portion of the testicle that delivers the sperm to the urethra it needs to be checked for lumps or shrinkage as this could mean there is an issue such as epididymitis the infection causes an inflammation of the epididymitis with permanent damage to sperm and delivery of viable semen reducing the breeding capacity of a ram.

Husbandry throughout the year

Preparatory tupping husbandry tasks

Round tailing

Round tailing is the cleaning up of the ewes tail before tupping, this is done because overtime wool growth and muck can build up to make access to the ewes vulva difficult for the ram. So it must be cleaned up to allow the least amount of complication for the ram. This can also help decrease the amount of issues the ram gets from genital infection and bacteria.

Foot trimming

Foot trimming tends to be done annually before flushing or when a problem is spotted (e.g. limping ewes). Issues should not be put off as this can lead to more severe cases by checking your flock every day you should be able to tell if any have foot rot. Using footbaths in high traffic areas is an effective preventative measure against foot ailments.

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If you have to treat a ewe more than once for foot rot it is advisable to cull it, this is because that ewe will harbor the infection and potentially spread it to the rest of the flock however this is quite an extreme approach.

Vaccinations

The most common thing for sheep to be vaccinated against is Clostridial and Pasteurella diseases as these are the most common, the two diseases are usually vaccinated against at the same time.

Farmers are advised to vaccinate their ewes against the clostridial diseases four weeks before lambing. It is advisable to vaccinate the flock as two separate groups with the later lambing ewes vaccinated one week to 10 days later than those ewes lambing in the first week. The ewes must be dry when they are vaccinated and care must be taken to ensure correct subcutaneous injection of every ewe. Subcutaneous injection of ewes when they are wet may result in contamination of the needle and abscess formation. Careful and gentle handling of the pregnant ewes is essential during the operation; speed is not important. Farm dogs should be kept out of the way whenever possible to reduce stress.

Worming

Although ewes are relatively worm resistant they need to be treated once or twice a year. If any ewes are in particularly poor condition score pre-tupping it could be beneficial to give them to give them a worming treatment to get them as healthy as possible pre-tupping.

It can also be beneficial to give the ewes a post-lambing treatment to cut down on the rise or worm levels in the spring and therefore reduce the worm intake to lambs who are far more susceptible.

Shearing

Pre-tupping during your ram MOT you need to make sure to shear your rams coat this is so he doesn’t overheat when exerting himself during the tupping period.

Otherwise you should shear your flock before the hotter seasons.

Flushing

This is when you put the ewes on a very high plane of nutrition 2-3 weeks before tupping, good nutrition will increase egg counts in the ewe and therefore increase fertility this also increases the likelihood of twins.

Husbandry tasks during tupping

Raddle

Attaching a raddle or some other sort of marking system to the rams (tactor grease mixed with marking spray also works). This is done so you can group ewes by expected conception date after tupping (colours are changed every few days), and if you are using novice ram this is also used to see how he’s doing.

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Disease Cause Symptoms PreventionTreatment, administration and suitable products

Clostridial diseases

It is caused by a bacteria that enters the intestines and quickly multiplies while creating toxins leading to illness

Loose bloody stool, lethargic, loss of appetite, kicking at stomach, restlessness, poor posture and loss of ability to stand up.

Vaccination four weeks before lambing is recommended as well as vaccinating in two separate groups 10 days after each other.

The disease is fatal in almost all cases except for a small percentage of cases of malignant oedema (bighead) and blackleg which receive veterinary treatment during the very early stages of disease.

Covexin® 10 is a suitable vaccine to use. Its administered subcutaneously.

Pasteurella pneumonia

This infection is caused by a bacteria.

Many cases develop quickly and result in death within 8–24 hrs. These animals often have fever, hyper salivation, nasal discharge, and difficult respiration.

A vaccination is recommended to be done at the same time as the clostridial vaccine.

An antibiotic treatment is suitable if it is caught early. Ox tetracycline is preferred as some strains are resistant.

Alamycin A 300 Solution for Injection, is a suitable product. This is administered intramuscularly.

Foot rot

Its caused by two bacteria interacting Fusobacterium necrophorum and Bacteroides nodosus causing infection in the foot.

Limping, foul odour of foot, separation of the horny tissues. Redness around the area and in very poor cases horn coming off.

Never bring in sheep from infected flocks, quarantine infectected sheep in separate areas. Have clean disease pasture. And disinfect areas that have had contact. Foot baths are also recommended.

Antiseptic spray is usually used on the area and an antibiotic is used. Foot trimming can also be used but only if deemed vital.

Pen & Strep Suspension For Injection is a suitable antibiotic which is administered via an intramuscular injection.

Fly strike most commonly caused by Lucilia sericata (Greenbottle) flys being attracted to the sheeps dirty rear and laying eggs in the wool which will then start feeding off

Agitation of the animal e.g. rubbing stomping etc…a foul odur will appear that will attract more flies, the wool will become dicoloured

Prevention is the best form of control. Strike can be prevented using pour-ons with insect growth regulators. However these products will not treat existing strike (maggots). There is some evidence that it is hereditary so culling of regularly struck sheep may help, also sheep with regulary dirty rears. Shearing will help temporarily but

It can be prevented with a pour-on solution. CLiK® which is sprayed on eqal sides of the backbone.

And it can be treated with Deltanil 10 mg/ml Pour-on Solution for cattle and sheep this will kill the maggots and

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the ewe causing damage/infection.

and fall off. Unchecked cases can lead to death.

the risk is still there with shaved sheep routine crutching started in april and repeated every 4-6 weeks. Tail docking is also recommended.

help the infection but it can’t stop further attacks. It is topically applied.

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Common diseases

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Coccidiosis

Its caused by a spore producing parasite Coccidiosis which is transmitted by ingesting the eggs. They multiply in the gut and damage the gut lining.

The common presenting signs of coccidiosis are a rapid loss of weight and diarrhoea containing mucus and flecks of blood, causing staining of the perineum and tail. Affected lambs are very dull and lifeless. Fresh blood and diarrhoea are signs of this disease.

Keep lambs off pasture which infected older sheep have used. If possible move feeders occasionally to stop the build-up of parisites near the feed area.

Treatments with diclazuril in are suitable In killing the parasite and reduce egg numbers.

Vecoxan 2.5 mg/ml Oral Suspension is a suitable medicine, its administered orally with a drenching gun.

Enzootic abortion

It’s caused by a bacterium called Chlamydophila abortus.

This disease causes the ewe to abort its lamb, the aborted material and placenta are highly infectious and it needs to be disposed of and destroyed.

There are 2 vaccines available to protect ewes against abortion caused by Chlamydophila: Enzovax®, (Intervet Schering Plough Animal Health), and CEVAC Chlamydia® (CEVA Animal Health Ltd).

Oxytetracycline can be used to treat in-lamb ewes during an outbreak to reduce the number of abortions.

Alamycin A 300 Solution for Injection contains

Oxytetracycline, therefore it is a suitable product. This is administered intramuscularly.

Toxoplasmosis

Its caused by a parasite Toxoplasma gondii that is spread by cats via faeces.

It will cause abortions in mid-late pregnancy and foetal loss in early pregnancy. It can also lead to mummified lambs.

Store feed in vermin proof facilities. Vaccines are available and should be administered 3-4 weeks before the breeding season.

Same treatment as above.

TOXOVAX® is available as a vaccine administered intramuscularly via injection. Follow up vaccine should be given 2 years after the first dose.

Mastitis

Is caused by a variety of bacteria infecting the udder.

Lumps in udder, milk consistency changes drastically, blood in milk, udders are hot, swollen and reddened.

Can lead to death in the lamb and the ewe if not treated.

Clean bedding should always be a priority, disinfecting areas routinely and avoiding dampness will all help prevent it.

Treat with penicillin after disinfecting the teat.

Pen & Strep Suspension For Injection is a suitable antibiotic which is administered via an intramuscular injection.

Sheep scab

Caused by a mite Psoroptes ovis.

It causes irritation to the sheep and can lead to yellowy lesions on the skin. Sheep with it tend to have areas of tatty loose wool or bare areas due to scratching.

Keep off farm sheep away, check new sheep have been dipped and get vets to check any signs of wool loss.

treatment would be either plunge dipping in diazinon or injection with doramectin or moxidectin.

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Scald

bacterium Fusobacterium necrophorum which causes damage to the superficial layer of the skin between the claws

It causes a white layer to form inbetween the toes and soreness of the feet. This can develop to be more severe and break down the foot as footrot.

Formalin footbaths, good pasture management, disinfecting areas routinely and good management will help prevent it.

A spray containing Oxytetracycline is suitable for individual treatment. For larger groups a 5% formalin foot bath is recommended.

Liver fluke

Caused by parisites that feed off the liver

Sheep affected tend to show signs of depression and a loss of appitite and condition. It usually isn’t spotted until the sheep suddenly dies.

There isn’t much in the way of prevention other than drenching with triclabendazole. Full proof of infection is mostly only possible post-mortem.

Fasinex® 100 (triclabendazole) is a suitable oral drench that will kill the parisites.

PGE

Caused by a parasite.

Signs are profuse diarrhoea reduced performance weight loss emaciation in some cases anaemia in some cases.

Regular anthelmintic oral drenching for worms is recommended.

ZOLVIX® is a suitable oral drench for killing the parasites.

Watery mouth

Caused by e.coli bacteria in the gut.

It causes lethargy diarrhoea and profuse salivation commonly.

Hard to prevent but regular disinfecting and clean areas/bedding should help.

Oral anti-biotics, soapy water enemas, oral eltrolyte therapy and amoxicillin injections are recommended.

Betamox LA 150mg/ml Suspension for Injection is a suitable intramuscular injection to treat it.

Preg Tox

Caused by an energy shortage in the ewe that is carrying many lambs

Disorientation, blindness, depression, muscle tremors and abortion. Head pressing may happen at later stages, It may eventually end in death.

Give high quality nutrition to ewes expected to have large amounts of lambs triplets/quads.

Give the ewe an energy solution such as an Intravenous glucose injection as soon as signs are spotted.

Glucose 5g/100 ml B. Braun is a suitable solution for treatment.

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This is an example veterinary medicine record. You are required by law to keep these records up to date.

Disposal of medicine.

Current uk controlled drugs laws require all unused/out of date drugs be disposed of when no longer usable e.g. not enough of that drug for another dose. Methods of disposal include pouring liquids in sawdust and breaking and dissolving pills in soapy water.

Example sheep flock health plan

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Selection programs

Sheep selection programs should be used in all sheep enterprises as they promote economically beneficial traits through selection, however it isn’t possible to improve all traits at once. Generally the more traits improved on the smaller the improvement individually. The first step in any selection program is to identify the traits of greatest economic importance. They may be growth rate, carcass merit, fleece traits, or reproductive efficiency.

The improvement that can be made depends on:

-Accurate measurement of the trait.

-Complete records on the flock.

-The amount of selection pressure applied.

-The amount of variation of the trait or different traits among individuals within the flock. If the sheep do not vary genetically, then no improvement can be made. If they vary greatly, then improvement will be rapid when producers select only the individuals that excel in the expression of important traits.

-The heritability of the trait. Variation in any economic trait is caused by genetic differences and environmental differences. Variation that results from differences in heredity is broadly defined as heritability.

Hybrids

Mixing breeds has an effect of hybrid vigour which has tended to show improvement in terms of trait. Generally, crossbred ewes exhibit a higher reproduction rate, produce more milk, and their lambs are stronger at birth. This makes them significantly more profitable than purebred flocks.

Other than these traits, there are other negative that you would want to breed out. Conditions like Entropion (in-turned eyelid) which is known to be hereditary or other issues such as ewes which constantly suffer a certain ailment e.g. prone to foot rot, fly strike etc…

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Heritability of traits in sheep

Trait Percent

Birth weight 0.15

Weaning weight (60 days of age) 0.20

Weaning weight (120 days of age) 0.25

Mature body weight 0.40

Rate of gain (post-weaning) 0.40

Face cover 0.35-0.55

Skin folds 0.20-0.50

Grease fleece weight 0.25-0.60

Clean fleece weight 0.25-0.60

Clean yield 0.30-0.40

Staple length 0.30-0.65

Fleece grade 0.20-0.60

Multiple birth 0.10

Milk production 0.10

Ewe productivity 0.20

Loin-eye area 0.35

Fat thickness over loin eye 0.30

Carcass weight 0.35

Retail cut weight 0.45

Dressing percentage 0.10

References

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Eradicatescrapie.org, (2015). NSEI: Scrapie Fact Sheet. [online] Available at: http://www.eradicatescrapie.org/About%20Scrapie/Fact%20Sheet.html [Accessed 24 Jan. 2015].

Farmanimalhealth.co.uk, (2015). Clik » Farm Animal Health. [online] Available at: http://www.farmanimalhealth.co.uk/sheep-clik [Accessed 23 Jan. 2015].

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Innovis.org.uk, (2015). Scrapie genotyping | Sheep | Breeding Services | Innovis: Breeding innovation. [online] Available at: http://www.innovis.org.uk/breedingservices/sheep/scrapiegenotyping.asp [Accessed 24 Jan. 2015].

Merckmanuals.com, (2015). Overview of Hemorrhagic Septicemia: Hemorrhagic Septicemia: Merck Veterinary Manual. [online] Available at: http://www.merckmanuals.com/vet/generalized_conditions/hemorrhagic_septicemia/overview_of_hemorrhagic_septicemia.html [Accessed 23 Jan. 2015].

Nadis.org.uk, (2015). NADIS - National Animal Disease Information Service. [online] Available at: http://www.nadis.org.uk/bulletins/eye-diseases-in-sheep.aspx [Accessed 23 Jan. 2015].

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Nadis.org.uk, (2015). NADIS - National Animal Disease Information Service. [online] Available at: http://www.nadis.org.uk/bulletins/clostridia-and-pasteurella-vaccination.aspx [Accessed 21 Jan. 2015].

Nadis.org.uk, (2015). NADIS - National Animal Disease Information Service. [online] Available at: http://www.nadis.org.uk/bulletins/liver-fluke-control-in-sheep.aspx [Accessed 23 Jan. 2015].

Norbrook.com, (2015). Norbrook Laboratories | Veterinary, Equine, Farm Animal and Pet Products. [online] Available at: http://www.norbrook.com/products/alamycin-la-300-solution-for-injection-300mg-ml [Accessed 23 Jan. 2015].

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