Abortion Control, Vaccination, and Prevention in the Ewe Suelee Robbe, DVM Veterinary Diagnostic and Production Animal Medicine Iowa State University

Abortion Control, Abortion Control, Vaccination, and Vaccination, and

Prevention in the EwePrevention in the Ewe

Abortion Control, Abortion Control, Vaccination, and Vaccination, and

Prevention in the EwePrevention in the Ewe

Suelee Robbe, DVM

Veterinary Diagnostic and Production Animal Medicine

Iowa State University

Suelee Robbe, DVM

Veterinary Diagnostic and Production Animal Medicine


What is a What is a NormalNormal Abortion Abortion Rate?Rate?

What is a What is a NormalNormal Abortion Abortion Rate?Rate?

Less than 1%Less than 1%Less than 1%Less than 1%

ovine abortionsovine abortionsovine abortionsovine abortions

• Use the diagnostic laboratoryUse the diagnostic laboratory• Do not put aborted fetuses in the Do not put aborted fetuses in the

freezerfreezer• 60%-70% are diagnosed as 60%-70% are diagnosed as

infectious causes of abortion.infectious causes of abortion.• Toxoplasma, Chlamydia, and Toxoplasma, Chlamydia, and

Campylobacter are the 3 most Campylobacter are the 3 most common causes.common causes.

• Use the diagnostic laboratoryUse the diagnostic laboratory• Do not put aborted fetuses in the Do not put aborted fetuses in the

freezerfreezer• 60%-70% are diagnosed as 60%-70% are diagnosed as

infectious causes of abortion.infectious causes of abortion.• Toxoplasma, Chlamydia, and Toxoplasma, Chlamydia, and

Campylobacter are the 3 most Campylobacter are the 3 most common causes.common causes.

Toxoplasma AbortionsToxoplasma AbortionsToxoplasma AbortionsToxoplasma Abortions

• Ewes that Ewes that are not are not immune to immune to Toxoplasma Toxoplasma are exposed are exposed during during pregnancy.pregnancy.

• Ewes that Ewes that are not are not immune to immune to Toxoplasma Toxoplasma are exposed are exposed during during pregnancy.pregnancy.

AbortionAbortion

Animals infected with Toxo in tissue

Animals infected with Toxo in tissue

Cats eat tissue anddefecate in sheepfeed or feed bunks

Cats eat tissue anddefecate in sheepfeed or feed bunks

Ewes unknowingly eat Toxo eggs

Ewes unknowingly eat Toxo eggs

Large amounts of infected tissue for cats to eat.

Large amounts of infected tissue for cats to eat.

Prevention of Toxoplasma Prevention of Toxoplasma AbortionsAbortions

Prevention of Toxoplasma Prevention of Toxoplasma AbortionsAbortions

•*Avoid having a *Avoid having a young/transientyoung/transient cat cat population.population.

•Avoid having ewes eat where cats Avoid having ewes eat where cats frequent.frequent.

•Make feed storage areas cat proof Make feed storage areas cat proof (tough to do).(tough to do).

•Maintain effective rodent control.Maintain effective rodent control.•Prevent cats from feeding on Prevent cats from feeding on

sheep/lamb carcasses.sheep/lamb carcasses.

•*Avoid having a *Avoid having a young/transientyoung/transient cat cat population.population.

•Avoid having ewes eat where cats Avoid having ewes eat where cats frequent.frequent.

•Make feed storage areas cat proof Make feed storage areas cat proof (tough to do).(tough to do).

•Maintain effective rodent control.Maintain effective rodent control.•Prevent cats from feeding on Prevent cats from feeding on

sheep/lamb carcasses.sheep/lamb carcasses.

Vaccination against Vaccination against ToxoplasmaToxoplasma

Vaccination against Vaccination against ToxoplasmaToxoplasma

• There is an effective vaccine in There is an effective vaccine in Europe.Europe.

• Feed ewe-lambs contaminated feed Feed ewe-lambs contaminated feed when they are not pregnant.when they are not pregnant.

• Once a ewe aborts (or exposed) she Once a ewe aborts (or exposed) she is immune.is immune.

• Ionophores have been used… This is Ionophores have been used… This is an illegal use, only partially effective.an illegal use, only partially effective.

• There is an effective vaccine in There is an effective vaccine in Europe.Europe.

• Feed ewe-lambs contaminated feed Feed ewe-lambs contaminated feed when they are not pregnant.when they are not pregnant.

• Once a ewe aborts (or exposed) she Once a ewe aborts (or exposed) she is immune.is immune.

• Ionophores have been used… This is Ionophores have been used… This is an illegal use, only partially effective.an illegal use, only partially effective.

Questions???Questions???Questions???Questions???

Chlamydia AbortionsChlamydia AbortionsChlamydia AbortionsChlamydia Abortions• Economically a very important disease for sheep producersEconomically a very important disease for sheep producers• Abortion occurs in the last trimesterAbortion occurs in the last trimester• Can be the cause of an abortion storm, but not usuallyCan be the cause of an abortion storm, but not usually• Lambs may also be carried full term, but are born dead or weak.Lambs may also be carried full term, but are born dead or weak.• Can be a chronic continual problem with 1-5% of ewes aborting annually. (Typical)Can be a chronic continual problem with 1-5% of ewes aborting annually. (Typical)

• Economically a very important disease for sheep producersEconomically a very important disease for sheep producers• Abortion occurs in the last trimesterAbortion occurs in the last trimester• Can be the cause of an abortion storm, but not usuallyCan be the cause of an abortion storm, but not usually• Lambs may also be carried full term, but are born dead or weak.Lambs may also be carried full term, but are born dead or weak.• Can be a chronic continual problem with 1-5% of ewes aborting annually. (Typical)Can be a chronic continual problem with 1-5% of ewes aborting annually. (Typical)

Chlamydial AbortionChlamydial AbortionChlamydial AbortionChlamydial Abortion• Ewes can become infected during one lambing season and abort the next lambing season.Ewes can become infected during one lambing season and abort the next lambing season.• A replacement ewe lamb infected at birth can harbor the organism and abort her lambs.A replacement ewe lamb infected at birth can harbor the organism and abort her lambs.• Ewes carrying multiple fetuses are more likely to abort Ewes carrying multiple fetuses are more likely to abort • There are flocks that are free of Chlamydia. (Or at least the strain that causes abortion.)There are flocks that are free of Chlamydia. (Or at least the strain that causes abortion.)

• Ewes can become infected during one lambing season and abort the next lambing season.Ewes can become infected during one lambing season and abort the next lambing season.• A replacement ewe lamb infected at birth can harbor the organism and abort her lambs.A replacement ewe lamb infected at birth can harbor the organism and abort her lambs.• Ewes carrying multiple fetuses are more likely to abort Ewes carrying multiple fetuses are more likely to abort • There are flocks that are free of Chlamydia. (Or at least the strain that causes abortion.)There are flocks that are free of Chlamydia. (Or at least the strain that causes abortion.)

Purchased Ewes can bring Chlamydia into a Clean Flock

Purchased Ewes can bring Chlamydia into a Clean Flock

Infected EweInfected Ewe

How Chlamydia Perpetuates in a FlockHow Chlamydia Perpetuates in a Flock

Carrier EweCarrier Ewe

Infects naive ewes Infects naive ewes

Many of these ewes will abort at next lambing and become carrier ewes

Many of these ewes will abort at next lambing and become carrier ewes

Lambs from these ewes can be born infected (will be carriers) and can abort their first lambs

Lambs from these ewes can be born infected (will be carriers) and can abort their first lambs

Infected flock of carrier ewes.

These ewes don’t abort.

Infected flock of carrier ewes.

These ewes don’t abort.

Their offspring are infected and some of them will abort at subsequent lambings

Their offspring are infected and some of them will abort at subsequent lambings

Chlamydia is perpetuated in the flock with mostly ewe-lambs and yearlings aborting ~1-5% rate annually.

Chlamydia is perpetuated in the flock with mostly ewe-lambs and yearlings aborting ~1-5% rate annually.

How Chlamydia Perpetuates in a Flock (cont.)

Controlling Chlamydial Controlling Chlamydial AbortionAbortion


• Use caution when selecting ewe lamb Use caution when selecting ewe lamb replacements.replacements.

• Run ewe lambs separate from main Run ewe lambs separate from main flock.flock.

• Lamb ewe lambs away from/ after Lamb ewe lambs away from/ after main flock.main flock.

• Immediately isolate aborting ewesImmediately isolate aborting ewes; ; consider culling them.consider culling them.

• Use caution when selecting ewe lamb Use caution when selecting ewe lamb replacements.replacements.

• Run ewe lambs separate from main Run ewe lambs separate from main flock.flock.

• Lamb ewe lambs away from/ after Lamb ewe lambs away from/ after main flock.main flock.

• Immediately isolate aborting ewesImmediately isolate aborting ewes; ; consider culling them.consider culling them.



• Pick up afterbirths, dead fetusesPick up afterbirths, dead fetuses and and throw barn lime down on the area if throw barn lime down on the area if appropriate.appropriate.

• Do not feed on the ground in a dry lot Do not feed on the ground in a dry lot situation.situation.

• Avoid crowding, have plenty of bunk Avoid crowding, have plenty of bunk space.space.

• Tetracycline to help prevent sheddingTetracycline to help prevent shedding

• Pick up afterbirths, dead fetusesPick up afterbirths, dead fetuses and and throw barn lime down on the area if throw barn lime down on the area if appropriate.appropriate.



• Tetracycline to help prevent sheddingTetracycline to help prevent shedding

Vaccination against Vaccination against ChlamydiaChlamydia

Vaccination against Vaccination against ChlamydiaChlamydia

• Vaccines Vaccines maymay decrease severity of initial decrease severity of initial infection.infection.

• Once a flock is infected, there is no Once a flock is infected, there is no evidence vaccine has any impact if all the evidence vaccine has any impact if all the studies are examined.studies are examined.

• Vaccines Vaccines maymay decrease severity of initial decrease severity of initial infection.infection.

• Once a flock is infected, there is no Once a flock is infected, there is no evidence vaccine has any impact if all the evidence vaccine has any impact if all the studies are examined.studies are examined.

Questions???Questions???Questions???Questions???

Campylobacter AbortionsCampylobacter AbortionsCampylobacter AbortionsCampylobacter Abortions

• Abortions occur in the last 6 weeks of Abortions occur in the last 6 weeks of pregnancy.pregnancy.

• Lambs may be carried full term, but Lambs may be carried full term, but are born dead or weak.are born dead or weak.

• Most common cause of abortion Most common cause of abortion storms with 5-50% aborting.storms with 5-50% aborting.

• Typically the disease is self-limiting. Typically the disease is self-limiting. (unlike Chlamydia)(unlike Chlamydia)

• Abortions occur in the last 6 weeks of Abortions occur in the last 6 weeks of pregnancy.pregnancy.

• Lambs may be carried full term, but Lambs may be carried full term, but are born dead or weak.are born dead or weak.

• Most common cause of abortion Most common cause of abortion storms with 5-50% aborting.storms with 5-50% aborting.

• Typically the disease is self-limiting. Typically the disease is self-limiting. (unlike Chlamydia)(unlike Chlamydia)

Campylobacter Abortions Campylobacter Abortions Campylobacter Abortions Campylobacter Abortions • Many sheep carry Campylobacter as normal Many sheep carry Campylobacter as normal

intestinal flora.intestinal flora.• Ewes Ewes ingestingest a new strain of Campylobacter. a new strain of Campylobacter.

If this happens after the 12If this happens after the 12thth week of week of pregnancy or later, the ewe very likely aborts. pregnancy or later, the ewe very likely aborts.

• Infection is further spread by direct contact Infection is further spread by direct contact with aborted fetus/membranes.with aborted fetus/membranes.

• Ewes that are not pregnant develop immunity Ewes that are not pregnant develop immunity and will not abort subsequent fetuses.and will not abort subsequent fetuses.

• Many sheep carry Campylobacter as normal Many sheep carry Campylobacter as normal intestinal flora.intestinal flora.

• Ewes Ewes ingestingest a new strain of Campylobacter. a new strain of Campylobacter. If this happens after the 12If this happens after the 12thth week of week of pregnancy or later, the ewe very likely aborts. pregnancy or later, the ewe very likely aborts.

• Infection is further spread by direct contact Infection is further spread by direct contact with aborted fetus/membranes.with aborted fetus/membranes.

• Ewes that are not pregnant develop immunity Ewes that are not pregnant develop immunity and will not abort subsequent fetuses.and will not abort subsequent fetuses.

Preventing Campylobacter Preventing Campylobacter AbortionsAbortions

Preventing Campylobacter Preventing Campylobacter AbortionsAbortions

• Have ewes thoroughly mixed Have ewes thoroughly mixed before breeding.before breeding.

• If you don’t have a closed ewe If you don’t have a closed ewe flock, consider vaccinating.flock, consider vaccinating.



• Have ewes thoroughly mixed Have ewes thoroughly mixed before breeding.before breeding.

• If you don’t have a closed ewe If you don’t have a closed ewe flock, consider vaccinating.flock, consider vaccinating.



Campylobacter Campylobacter VaccinationVaccination

Campylobacter Campylobacter VaccinationVaccination

• One of the poorest vaccines routinely One of the poorest vaccines routinely recommended by sheep health experts.recommended by sheep health experts.

• At best 80% efficacy, probably closer to At best 80% efficacy, probably closer to 0%.0%.

• Efficacy depends on strain of Efficacy depends on strain of campylobacter.campylobacter.

• Don’t rely on vaccination in place of Don’t rely on vaccination in place of good management.good management.

• One of the poorest vaccines routinely One of the poorest vaccines routinely recommended by sheep health experts.recommended by sheep health experts.

• At best 80% efficacy, probably closer to At best 80% efficacy, probably closer to 0%.0%.

• Efficacy depends on strain of Efficacy depends on strain of campylobacter.campylobacter.

• Don’t rely on vaccination in place of Don’t rely on vaccination in place of good management.good management.

Lamb/Sheep Quality Lamb/Sheep Quality AssuranceAssurance

Lamb/Sheep Quality Lamb/Sheep Quality AssuranceAssurance

Suelee Robbe, DVM

Veterinary diagnostic and Production Animal Medicine


Suelee Robbe, DVM

Veterinary diagnostic and Production Animal Medicine


Quality Assurance Quality Assurance ProgramsPrograms

Quality Assurance Quality Assurance ProgramsPrograms

• Standardized methods of handling, Standardized methods of handling, treating, and processing food treating, and processing food animals to help ensure quality and animals to help ensure quality and wholesomeness to the consumer.wholesomeness to the consumer.

• Standardized methods of handling, Standardized methods of handling, treating, and processing food treating, and processing food animals to help ensure quality and animals to help ensure quality and wholesomeness to the consumer.wholesomeness to the consumer.

Where is the sheep industry in this picture?

Where is the sheep industry in this picture?

Goals of a Quality Goals of a Quality Assurance program for Assurance program for

SheepSheep


SheepSheep• Keep muscle damage down to a minimum. Keep muscle damage down to a minimum.

(Injection sites, bruises, etc…)(Injection sites, bruises, etc…)

• Eliminate illegal drug residues and foreign Eliminate illegal drug residues and foreign objects. objects.

• Prudent use of extra-label drugs.Prudent use of extra-label drugs.

• Consistent meat “eating quality”Consistent meat “eating quality”

• Wool QA.Wool QA.

• Keep muscle damage down to a minimum. Keep muscle damage down to a minimum. (Injection sites, bruises, etc…)(Injection sites, bruises, etc…)

• Eliminate illegal drug residues and foreign Eliminate illegal drug residues and foreign objects. objects.




Minimizing Injection Site Minimizing Injection Site DamageDamage


• Syringe handling and careSyringe handling and care Rinse after each use. Rinse after each use. Allow syringe to dry thoroughly.Allow syringe to dry thoroughly. Do not use soap to clean. (unless NO Do not use soap to clean. (unless NO

MLV products are used)MLV products are used) Lube plungers with approved Lube plungers with approved

products.products.

• Syringe handling and careSyringe handling and care Rinse after each use. Rinse after each use. Allow syringe to dry thoroughly.Allow syringe to dry thoroughly. Do not use soap to clean. (unless NO Do not use soap to clean. (unless NO

MLV products are used)MLV products are used) Lube plungers with approved Lube plungers with approved

products.products.



• Needle handlingNeedle handling– Stainless Steel, DisposableStainless Steel, Disposable– Different needle for drawing out of a Different needle for drawing out of a

multi-dose bottle.multi-dose bottle.– Change after bent, burred needles.Change after bent, burred needles.

• Needle handlingNeedle handling– Stainless Steel, DisposableStainless Steel, Disposable– Different needle for drawing out of a Different needle for drawing out of a

multi-dose bottle.multi-dose bottle.– Change after bent, burred needles.Change after bent, burred needles.

Needles (SQ)Needles (SQ)Needles (SQ)Needles (SQ)• Acceptable needlesAcceptable needles

18 gauge by ½ inch (5/8 inch in 18 gauge by ½ inch (5/8 inch in disposable)disposable)

20 gauge by ½ inch20 gauge by ½ inch

• Acceptable areasAcceptable areas Neck (preferred)Neck (preferred) Behind elbowBehind elbow Inside loose skin of the flank (Only on Inside loose skin of the flank (Only on

lambs)lambs)

• Acceptable needlesAcceptable needles 18 gauge by ½ inch (5/8 inch in 18 gauge by ½ inch (5/8 inch in

disposable)disposable) 20 gauge by ½ inch20 gauge by ½ inch

• Acceptable areasAcceptable areas Neck (preferred)Neck (preferred) Behind elbowBehind elbow Inside loose skin of the flank (Only on Inside loose skin of the flank (Only on

lambs)lambs)

Needles (IM)Needles (IM)Needles (IM)Needles (IM)

• (Avoid if possible)(Avoid if possible)– 16 gauge by ¾ inch16 gauge by ¾ inch– 18 gauge by ¾ inch18 gauge by ¾ inch– 20 gauge by ¾ inch20 gauge by ¾ inch

• Neck onlyNeck only!!

• (Avoid if possible)(Avoid if possible)– 16 gauge by ¾ inch16 gauge by ¾ inch– 18 gauge by ¾ inch18 gauge by ¾ inch– 20 gauge by ¾ inch20 gauge by ¾ inch

• Neck onlyNeck only!!

SQ, IM

SQ

QA GuidelinesQA Guidelines (cont.) (cont.)QA GuidelinesQA Guidelines (cont.) (cont.)

• Follow Label instructions.Follow Label instructions.• Never mix products in one injection.Never mix products in one injection.• Never put more than 10 cc’s per site Never put more than 10 cc’s per site

in adult ewes, 5 cc’s in lambs, in adult ewes, 5 cc’s in lambs, feeder lambs.feeder lambs.

• Know the Products you are using.Know the Products you are using.• Follow common sense.Follow common sense.

• Follow Label instructions.Follow Label instructions.• Never mix products in one injection.Never mix products in one injection.• Never put more than 10 cc’s per site Never put more than 10 cc’s per site

in adult ewes, 5 cc’s in lambs, in adult ewes, 5 cc’s in lambs, feeder lambs.feeder lambs.

• Know the Products you are using.Know the Products you are using.• Follow common sense.Follow common sense.


SheepSheep


SheepSheep• Keep muscle damage down to a minimum. Keep muscle damage down to a minimum.

(Injection sites, bruises, etc…)(Injection sites, bruises, etc…)

• Eliminate illegal drug residues and foreign Eliminate illegal drug residues and foreign objects.objects.




• Keep muscle damage down to a minimum. Keep muscle damage down to a minimum. (Injection sites, bruises, etc…)(Injection sites, bruises, etc…)

• Eliminate illegal drug residues and foreign Eliminate illegal drug residues and foreign objects.objects.




Eliminating Drug Eliminating Drug ResiduesResidues

Eliminating Drug Eliminating Drug ResiduesResidues

• Understand and adhere to withdrawal Understand and adhere to withdrawal times.times.

• Do not use drugs that are not Do not use drugs that are not approved for use in sheep without approved for use in sheep without veterinary approval.veterinary approval.– This includes topical insecticides, over This includes topical insecticides, over

the counter human remedies, etcthe counter human remedies, etc……

• Understand and adhere to withdrawal Understand and adhere to withdrawal times.times.

• Do not use drugs that are not Do not use drugs that are not approved for use in sheep without approved for use in sheep without veterinary approval.veterinary approval.– This includes topical insecticides, over This includes topical insecticides, over

the counter human remedies, etcthe counter human remedies, etc……

What are the sheep Approved What are the sheep Approved Antibiotics?Antibiotics?

What are the sheep Approved What are the sheep Approved Antibiotics?Antibiotics?

• Erythromycin/ Gallimycin Erythromycin/ Gallimycin – Unacceptable Tissue reactivityUnacceptable Tissue reactivity..

• PenicillinPenicillin – 3000 units per pound of body weight or 1.0 ml (cc) for 3000 units per pound of body weight or 1.0 ml (cc) for

each 100 lbs. once daily.each 100 lbs. once daily.

• NaxcelNaxcel (ceftiofur) (prescription use only)(ceftiofur) (prescription use only)

– 0.5-1 mg/lb. IM (If reconstituted per label directions, 1-2 0.5-1 mg/lb. IM (If reconstituted per label directions, 1-2 cc/100 lbs.) cc/100 lbs.)

• If these drugs are used any way other than the label, it must If these drugs are used any way other than the label, it must be done with veterinary approval.be done with veterinary approval.

• Erythromycin/ Gallimycin Erythromycin/ Gallimycin – Unacceptable Tissue reactivityUnacceptable Tissue reactivity..

• PenicillinPenicillin – 3000 units per pound of body weight or 1.0 ml (cc) for 3000 units per pound of body weight or 1.0 ml (cc) for

each 100 lbs. once daily.each 100 lbs. once daily.

• NaxcelNaxcel (ceftiofur) (prescription use only)(ceftiofur) (prescription use only)

– 0.5-1 mg/lb. IM (If reconstituted per label directions, 1-2 0.5-1 mg/lb. IM (If reconstituted per label directions, 1-2 cc/100 lbs.) cc/100 lbs.)

• If these drugs are used any way other than the label, it must If these drugs are used any way other than the label, it must be done with veterinary approval.be done with veterinary approval.

When can we use Drugs When can we use Drugs that are Not Approved for that are Not Approved for

Sheep?Sheep?

When can we use Drugs When can we use Drugs that are Not Approved for that are Not Approved for

Sheep?Sheep?• This is addressed in a law that was passed This is addressed in a law that was passed

called AMDUCA (Animal Medicinal Drug Use called AMDUCA (Animal Medicinal Drug Use Clarification Act).Clarification Act).

• This act gives veterinarians the right to use This act gives veterinarians the right to use and recommend the use of drugs that are not and recommend the use of drugs that are not approved for use in sheep. approved for use in sheep.

(ONLY under certain circumstances)(ONLY under certain circumstances)

• This is addressed in a law that was passed This is addressed in a law that was passed called AMDUCA (Animal Medicinal Drug Use called AMDUCA (Animal Medicinal Drug Use Clarification Act).Clarification Act).

• This act gives veterinarians the right to use This act gives veterinarians the right to use and recommend the use of drugs that are not and recommend the use of drugs that are not approved for use in sheep. approved for use in sheep.

(ONLY under certain circumstances)(ONLY under certain circumstances)

AMDUCAAMDUCAAMDUCAAMDUCA• A valid VCPR exists.A valid VCPR exists.• The health of the animal is at immediate risk and The health of the animal is at immediate risk and

suffering or death would result if a drug were not suffering or death would result if a drug were not usedused..

• There is not an approved drug on the market for There is not an approved drug on the market for that particular condition.that particular condition.

• Accurate records of usage are keptAccurate records of usage are kept• Treated animals can be easily identified for an Treated animals can be easily identified for an

extended period.extended period.• An extended withdrawal time is used to assure An extended withdrawal time is used to assure

that no illegal residue occurs.that no illegal residue occurs.

• A valid VCPR exists.A valid VCPR exists.• The health of the animal is at immediate risk and The health of the animal is at immediate risk and

suffering or death would result if a drug were not suffering or death would result if a drug were not usedused..

• There is not an approved drug on the market for There is not an approved drug on the market for that particular condition.that particular condition.

• Accurate records of usage are keptAccurate records of usage are kept• Treated animals can be easily identified for an Treated animals can be easily identified for an

extended period.extended period.• An extended withdrawal time is used to assure An extended withdrawal time is used to assure

that no illegal residue occurs.that no illegal residue occurs.

AMDUCA AMDUCA (cont.)(cont.)AMDUCA AMDUCA (cont.)(cont.)

• The veterinarian and producer accept The veterinarian and producer accept full responsibility for any illegal residue full responsibility for any illegal residue that occurs.that occurs.

• The veterinarian and producer accept The veterinarian and producer accept full responsibility for any illegal residue full responsibility for any illegal residue that occurs.that occurs.

Recommendations to Recommendations to Producers for Prudent Producers for Prudent

Antibiotic UseAntibiotic Use

Recommendations to Recommendations to Producers for Prudent Producers for Prudent

Antibiotic UseAntibiotic Use• BeforeBefore treatment is given, a diagnosis treatment is given, a diagnosis

must be made by you, or your veterinarian.must be made by you, or your veterinarian.• Use a sheep veterinarian that gives you Use a sheep veterinarian that gives you

treatment protocols. (preferably written)treatment protocols. (preferably written)• Follow your sheep veterinarian’s advice Follow your sheep veterinarian’s advice

and give feedback.and give feedback.• Every time you give an antibiotic Every time you give an antibiotic

understand and adhere to the withdrawal understand and adhere to the withdrawal time.time.

• Keep Appropriate RecordsKeep Appropriate Records

• BeforeBefore treatment is given, a diagnosis treatment is given, a diagnosis must be made by you, or your veterinarian.must be made by you, or your veterinarian.

• Use a sheep veterinarian that gives you Use a sheep veterinarian that gives you treatment protocols. (preferably written)treatment protocols. (preferably written)

• Follow your sheep veterinarian’s advice Follow your sheep veterinarian’s advice and give feedback.and give feedback.

• Every time you give an antibiotic Every time you give an antibiotic understand and adhere to the withdrawal understand and adhere to the withdrawal time.time.

• Keep Appropriate RecordsKeep Appropriate Records

Veterinarians Role in the Veterinarians Role in the Sheep IndustrySheep Industry

Veterinarians Role in the Veterinarians Role in the Sheep IndustrySheep Industry

• We must be able to justify ourselves We must be able to justify ourselves economically.economically.

• Medicine on a Flock basisMedicine on a Flock basis– QA, Protocols, outbreak treatments, QA, Protocols, outbreak treatments,

diagnostic assistance.diagnostic assistance.

• Prevention of Disease on a Flock Prevention of Disease on a Flock basis.basis.– Biosecurity Protocols, Risk AssessmentsBiosecurity Protocols, Risk Assessments

• We must be able to justify ourselves We must be able to justify ourselves economically.economically.

• Medicine on a Flock basisMedicine on a Flock basis– QA, Protocols, outbreak treatments, QA, Protocols, outbreak treatments,

diagnostic assistance.diagnostic assistance.

• Prevention of Disease on a Flock Prevention of Disease on a Flock basis.basis.– Biosecurity Protocols, Risk AssessmentsBiosecurity Protocols, Risk Assessments

Parasite Control ProgramsParasite Control ProgramsParasite Control ProgramsParasite Control Programs

Suelee Robbe, DVM, MSSuelee Robbe, DVM, MSDiagnostic and Production Animal Diagnostic and Production Animal Medicine, Iowa State UniversityMedicine, Iowa State University

Suelee Robbe, DVM, MSSuelee Robbe, DVM, MSDiagnostic and Production Animal Diagnostic and Production Animal Medicine, Iowa State UniversityMedicine, Iowa State University

Typical parasitic lifestyleTypical parasitic lifestyleTypical parasitic lifestyleTypical parasitic lifestyleAdults-Hang out in the GI tractAdults-Hang out in the GI tract• AbomasumAbomasum

– Haemonchus , Ostertagia, some Haemonchus , Ostertagia, some Trichostrongylus Trichostrongylus

• Small intestine Small intestine – Trichostrongylus, NematodirusTrichostrongylus, Nematodirus

• May live for longer than a year, but May live for longer than a year, but usually egg production peaks ~ 3 usually egg production peaks ~ 3 monthsmonths

Adults-Hang out in the GI tractAdults-Hang out in the GI tract• AbomasumAbomasum

– Haemonchus , Ostertagia, some Haemonchus , Ostertagia, some Trichostrongylus Trichostrongylus

• Small intestine Small intestine – Trichostrongylus, NematodirusTrichostrongylus, Nematodirus

• May live for longer than a year, but May live for longer than a year, but usually egg production peaks ~ 3 usually egg production peaks ~ 3 monthsmonths

Typical parasitic lifestyleTypical parasitic lifestyleTypical parasitic lifestyleTypical parasitic lifestyle

Eggs: Eggs:

Development from egg to infective (L3) Development from egg to infective (L3) larvae can occur as early as 6 dayslarvae can occur as early as 6 days

Molt into L1’s in the egg then hatchMolt into L1’s in the egg then hatch

Nematodirus develop into L3’s in the Nematodirus develop into L3’s in the egg, then hatchegg, then hatch

Most ova do not survive very cold Most ova do not survive very cold ambient temperaturesambient temperatures

Eggs: Eggs:

Development from egg to infective (L3) Development from egg to infective (L3) larvae can occur as early as 6 dayslarvae can occur as early as 6 days

Molt into L1’s in the egg then hatchMolt into L1’s in the egg then hatch

Nematodirus develop into L3’s in the Nematodirus develop into L3’s in the egg, then hatchegg, then hatch

Most ova do not survive very cold Most ova do not survive very cold ambient temperaturesambient temperatures


• L3’s - infective stageL3’s - infective stage• Thick cuticle protects them from Thick cuticle protects them from

dryingdrying– Cannot feed - finite life spanCannot feed - finite life span– Warm temperatures increase their Warm temperatures increase their

metabolic rate. metabolic rate.

• Can survive some freezingCan survive some freezing

• L3’s - infective stageL3’s - infective stage• Thick cuticle protects them from Thick cuticle protects them from

dryingdrying– Cannot feed - finite life spanCannot feed - finite life span– Warm temperatures increase their Warm temperatures increase their

metabolic rate. metabolic rate.

• Can survive some freezingCan survive some freezing


• L3’s molt in to L4’s soon after their L3’s molt in to L4’s soon after their ingestion where they may “rest for ingestion where they may “rest for a time”a time”

• HypobiosisHypobiosis

• occurs in most species of wormsoccurs in most species of worms

• L3’s molt in to L4’s soon after their L3’s molt in to L4’s soon after their ingestion where they may “rest for ingestion where they may “rest for a time”a time”

• HypobiosisHypobiosis

• occurs in most species of wormsoccurs in most species of worms

HaemonchusHaemonchusHaemonchusHaemonchus

• Adults live in abomasumAdults live in abomasum– ingest 0.05ml blood/worm/dayingest 0.05ml blood/worm/day– 5000 worms will remove 250 ml of 5000 worms will remove 250 ml of

blood.blood.

• Adults are very prolific egg layersAdults are very prolific egg layers• Haemonchus L3’s are not as cold Haemonchus L3’s are not as cold

hardy as othershardy as others• Most L3’s live for 1-3 monthsMost L3’s live for 1-3 months

• Adults live in abomasumAdults live in abomasum– ingest 0.05ml blood/worm/dayingest 0.05ml blood/worm/day– 5000 worms will remove 250 ml of 5000 worms will remove 250 ml of

blood.blood.

• Adults are very prolific egg layersAdults are very prolific egg layers• Haemonchus L3’s are not as cold Haemonchus L3’s are not as cold

hardy as othershardy as others• Most L3’s live for 1-3 monthsMost L3’s live for 1-3 months

Others parasitesOthers parasitesOthers parasitesOthers parasites

• NematodirusNematodirus• OstertagiaOstertagia• TrichostrongylusTrichostrongylus

• Plan your parasite program to Plan your parasite program to control haemonchuscontrol haemonchus

• NematodirusNematodirus• OstertagiaOstertagia• TrichostrongylusTrichostrongylus

• Plan your parasite program to Plan your parasite program to control haemonchuscontrol haemonchus

CoccidiaCoccidiaCoccidiaCoccidia

• All sheep shed coccidiaAll sheep shed coccidia

• Clinical signsClinical signs– Sudden deathSudden death– Scouring lambsScouring lambs– weight lossweight loss

• All sheep shed coccidiaAll sheep shed coccidia

• Clinical signsClinical signs– Sudden deathSudden death– Scouring lambsScouring lambs– weight lossweight loss

PreventionPreventionPreventionPrevention

• Keep environment clean and dryKeep environment clean and dry• Design feed and water bunks so Design feed and water bunks so

lambs cannot step in themlambs cannot step in them• Feed coccidiostats Feed coccidiostats

– DecoxDecox– BovatecBovatec

• Keep environment clean and dryKeep environment clean and dry• Design feed and water bunks so Design feed and water bunks so

lambs cannot step in themlambs cannot step in them• Feed coccidiostats Feed coccidiostats

– DecoxDecox– BovatecBovatec

TreatmentTreatmentTreatmentTreatment

• AmproliumAmprolium• Sulfa drugsSulfa drugs

• AmproliumAmprolium• Sulfa drugsSulfa drugs

Parasite controlParasite controlParasite controlParasite control

• Control of L3’s on pasture is critical, Control of L3’s on pasture is critical, and is related to number of adults in and is related to number of adults in the animal.the animal.

• A parasite program that:A parasite program that:

Targets L3’s controls the parasite Targets L3’s controls the parasite burdens in grazing sheep.burdens in grazing sheep.

Targets L4’s and adults in the animal Targets L4’s and adults in the animal does not necessarily control L3’s on does not necessarily control L3’s on pasture.pasture.

• Control of L3’s on pasture is critical, Control of L3’s on pasture is critical, and is related to number of adults in and is related to number of adults in the animal.the animal.

• A parasite program that:A parasite program that:

Targets L3’s controls the parasite Targets L3’s controls the parasite burdens in grazing sheep.burdens in grazing sheep.

Targets L4’s and adults in the animal Targets L4’s and adults in the animal does not necessarily control L3’s on does not necessarily control L3’s on pasture.pasture.

Example Sheep flockExample Sheep flock

Remote Pasture

Close PastureWorking facility/barns

Moves here in the summer.

Winter close up pasture.

Example Sheep and goat flockExample Sheep and goat flock

Remote Pasture


Flock here since June 20

FEC Aug 1st.

Dewormed Dectomax Sept 2

Wants to move here Sept. 30

last sheep/goat July 4th

Example Sheep and goat flockExample Sheep and goat flock

Remote Pasture


L3 Burden in Sept/Oct?

L3 Burden in Oct?

HIGHHIGH LOWLOW

Parasite control programsParasite control programsParasite control programsParasite control programs

• Development and survival of Development and survival of infective larvae depend on infective larvae depend on temperature and moisture. temperature and moisture.

• Optimums vary with worm species.Optimums vary with worm species.

• Development and survival of Development and survival of infective larvae depend on infective larvae depend on temperature and moisture. temperature and moisture.

• Optimums vary with worm species.Optimums vary with worm species.


• Host Resistance depends onHost Resistance depends on– AgeAge– VigorVigor– Genetic constitutionGenetic constitution– Presence or absence of established Presence or absence of established

parasite infectionsparasite infections– Acquired immunityAcquired immunity

• Host Resistance depends onHost Resistance depends on– AgeAge– VigorVigor– Genetic constitutionGenetic constitution– Presence or absence of established Presence or absence of established

parasite infectionsparasite infections– Acquired immunityAcquired immunity


• Maturation of 4th stage larvae in Maturation of 4th stage larvae in host may be arrested.host may be arrested.

• Maturation of 4th stage larvae in Maturation of 4th stage larvae in host may be arrested.host may be arrested.

AnthelmenticsAnthelmenticsAnthelmenticsAnthelmenticsLong actingLong acting• ivermectin-larvicidal ~10 daysivermectin-larvicidal ~10 days• doramectin -larvicidal ~20 daysdoramectin -larvicidal ~20 days• eprinomectineprinomectin• moxidectinmoxidectin

Pour-ons do not work in sheepPour-ons do not work in sheep

Disadvantages: Parasite resistance, Disadvantages: Parasite resistance, cost, WDT, Not Ovicidalcost, WDT, Not Ovicidal

Long actingLong acting• ivermectin-larvicidal ~10 daysivermectin-larvicidal ~10 days• doramectin -larvicidal ~20 daysdoramectin -larvicidal ~20 days• eprinomectineprinomectin• moxidectinmoxidectin

Pour-ons do not work in sheepPour-ons do not work in sheep

Disadvantages: Parasite resistance, Disadvantages: Parasite resistance, cost, WDT, Not Ovicidalcost, WDT, Not Ovicidal

AnthelmenticsAnthelmenticsAnthelmenticsAnthelmenticsShort acting or purge Short acting or purge • levamisolelevamisole

– relatively poor against immature or arrested relatively poor against immature or arrested L4 larvaeL4 larvae

– Low margin of safetyLow margin of safety

• benzimidazoles (fenbendazole, benzimidazoles (fenbendazole, oxfendazole, albendazole)oxfendazole, albendazole)

These products are ovicidalThese products are ovicidal

Short acting or purge Short acting or purge • levamisolelevamisole

– relatively poor against immature or arrested relatively poor against immature or arrested L4 larvaeL4 larvae

– Low margin of safetyLow margin of safety

• benzimidazoles (fenbendazole, benzimidazoles (fenbendazole, oxfendazole, albendazole)oxfendazole, albendazole)

These products are ovicidalThese products are ovicidal

Host resistance issuesHost resistance issuesHost resistance issuesHost resistance issues

• kids typically more susceptiblekids typically more susceptible• goats producing more milk goats producing more milk

typically have higher parasite typically have higher parasite burdensburdens

• animals under stress/have pre-animals under stress/have pre-existing conditions are more likely existing conditions are more likely have higher parasite burdenshave higher parasite burdens

• kids typically more susceptiblekids typically more susceptible• goats producing more milk goats producing more milk

typically have higher parasite typically have higher parasite burdensburdens

• animals under stress/have pre-animals under stress/have pre-existing conditions are more likely existing conditions are more likely have higher parasite burdenshave higher parasite burdens

Parasite ResistanceParasite ResistanceParasite ResistanceParasite Resistance

• The best way to avoid resistance to The best way to avoid resistance to an anthelmintic is not to use it.an anthelmintic is not to use it.

• If you rely on just anthelmintics as If you rely on just anthelmintics as your sole parasite control program your sole parasite control program you WILL get resistance. you WILL get resistance.

• There never has been and most There never has been and most likely never will be an anthelmintic likely never will be an anthelmintic that won’t have resistance problemsthat won’t have resistance problems

• The best way to avoid resistance to The best way to avoid resistance to an anthelmintic is not to use it.an anthelmintic is not to use it.

• If you rely on just anthelmintics as If you rely on just anthelmintics as your sole parasite control program your sole parasite control program you WILL get resistance. you WILL get resistance.

• There never has been and most There never has been and most likely never will be an anthelmintic likely never will be an anthelmintic that won’t have resistance problemsthat won’t have resistance problems

Documents

Abortion Control, Vaccination, and Prevention in the Ewe Suelee Robbe, DVM Veterinary Diagnostic and Production Animal Medicine Iowa State University