Abortion Control, Vaccination, and Prevention in the Ewe

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Abortion Control, Vaccination, and Prevention in
the Ewe
Suelee Robbe, DVM Veterinary Diagnostic and
Production Animal Medicine Iowa State University
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What is a Normal Abortion Rate?

• Less than 1

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ovine abortions

• Use the diagnostic laboratory
• Do not put aborted fetuses in the freezer
• 60-70 are diagnosed as infectious causes of
  abortion.
• Toxoplasma, Chlamydia, and Campylobacter are the
  3 most common causes.

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Toxoplasma Abortions

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

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Cats eat tissue and defecate in sheep feed or
feed bunks
Animals infected with Toxo in tissue
Ewes unknowingly eat Toxo eggs
Abortion
Large amounts of infected tissue for cats to eat.
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Prevention of Toxoplasma Abortions

• Avoid having a young/transient cat population.
• Avoid having ewes eat where cats frequent.
• Make feed storage areas cat proof (tough to do).
• Maintain effective rodent control.
• Prevent cats from feeding on sheep/lamb
  carcasses.

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Vaccination against Toxoplasma

• There is an effective vaccine in Europe.
• Feed ewe-lambs contaminated feed when they are
  not pregnant.
• Once a ewe aborts (or exposed) she is immune.
• Ionophores have been used This is an illegal
  use, only partially effective.

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Questions???
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Chlamydia Abortions

• Economically a very important disease for sheep
  producers
• Abortion occurs in the last trimester
• Can be the cause of an abortion storm, but not
  usually
• 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)

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Chlamydial Abortion

• 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.
• 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.)

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Purchased Ewes can bring Chlamydia into a Clean
Flock
Infected Ewe
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How Chlamydia Perpetuates in a Flock
Lambs from these ewes can be born infected (will
be carriers) and can abort their first lambs
Many of these ewes will abort at next lambing and
become carrier ewes
Infects naive ewes
Carrier Ewe
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How Chlamydia Perpetuates in a Flock (cont.)
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.
Infected flock of carrier ewes. These ewes dont
abort.
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Controlling Chlamydial Abortion

• Use caution when selecting ewe lamb replacements.
• Run ewe lambs separate from main flock.
• Lamb ewe lambs away from/ after main flock.
• Immediately isolate aborting ewes consider
  culling them.

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Controlling Chlamydial Abortion

• Pick up afterbirths, dead fetuses and throw barn
  lime down on the area if appropriate.
• Do not feed on the ground in a dry lot situation.
• Avoid crowding, have plenty of bunk space.
• Tetracycline to help prevent shedding

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Vaccination against Chlamydia

• Vaccines may decrease severity of initial
  infection.
• Once a flock is infected, there is no evidence
  vaccine has any impact if all the studies are
  examined.

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Questions???
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Campylobacter Abortions

• Abortions occur in the last 6 weeks of pregnancy.
• Lambs may be carried full term, but are born dead
  or weak.
• Most common cause of abortion storms with 5-50
  aborting.
• Typically the disease is self-limiting. (unlike
  Chlamydia)

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Campylobacter Abortions

• Many sheep carry Campylobacter as normal
  intestinal flora.
• Ewes ingest a new strain of Campylobacter. If
  this happens after the 12th week of pregnancy or
  later, the ewe very likely aborts.
• Infection is further spread by direct contact
  with aborted fetus/membranes.
• Ewes that are not pregnant develop immunity and
  will not abort subsequent fetuses.

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Preventing Campylobacter Abortions

• Have ewes thoroughly mixed before breeding.
• If you dont have a closed ewe flock, consider
  vaccinating.
• Do not feed on the ground in a dry lot situation.
• Avoid crowding, have plenty of bunk space.

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Campylobacter Vaccination

• One of the poorest vaccines routinely recommended
  by sheep health experts.
• At best 80 efficacy, probably closer to 0.
• Efficacy depends on strain of campylobacter.
• Dont rely on vaccination in place of good
  management.

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Lamb/Sheep Quality Assurance
Suelee Robbe, DVM Veterinary diagnostic and
Production Animal Medicine Iowa State University
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Quality Assurance Programs

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

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Where is the sheep industry in this picture?
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Goals of a Quality Assurance program for Sheep

• Keep muscle damage down to a minimum. (Injection
  sites, bruises, etc)
• Eliminate illegal drug residues and foreign
  objects.
• Prudent use of extra-label drugs.
• Consistent meat eating quality
• Wool QA.

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Minimizing Injection Site Damage

• Syringe handling and care
• Rinse after each use.
• Allow syringe to dry thoroughly.
• Do not use soap to clean. (unless NO MLV products
  are used)
• Lube plungers with approved products.

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Minimizing Injection Site Damage

• Needle handling
• Stainless Steel, Disposable
• Different needle for drawing out of a multi-dose
  bottle.
• Change after bent, burred needles.

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Needles (SQ)

• Acceptable needles
• 18 gauge by ½ inch (5/8 inch in disposable)
• 20 gauge by ½ inch
• Acceptable areas
• Neck (preferred)
• Behind elbow
• Inside loose skin of the flank (Only on lambs)

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Needles (IM)

• (Avoid if possible)
• 16 gauge by ¾ inch
• 18 gauge by ¾ inch
• 20 gauge by ¾ inch
• Neck only!

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SQ, IM
SQ
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QA Guidelines (cont.)

• Follow Label instructions.
• Never mix products in one injection.
• Never put more than 10 ccs per site in adult
  ewes, 5 ccs in lambs, feeder lambs.
• Know the Products you are using.
• Follow common sense.

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Goals of a Quality Assurance program for Sheep

• Keep muscle damage down to a minimum. (Injection
  sites, bruises, etc)
• Eliminate illegal drug residues and foreign
  objects.
• Prudent use of extra-label drugs.
• Consistent meat eating quality
• Wool QA.

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Eliminating Drug Residues

• Understand and adhere to withdrawal times.
• Do not use drugs that are not approved for use in
  sheep without veterinary approval.
• This includes topical insecticides, over the
  counter human remedies, etc

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What are the sheep Approved Antibiotics?

• Erythromycin/ Gallimycin
• Unacceptable Tissue reactivity.
• Penicillin
• 3000 units per pound of body weight or 1.0 ml
  (cc) for each 100 lbs. once daily.
• Naxcel (ceftiofur) (prescription use only)
• 0.5-1 mg/lb. IM (If reconstituted per label
  directions, 1-2 cc/100 lbs.)
  
• If these drugs are used any way other than the
  label, it must be done with veterinary approval.

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

• This is addressed in a law that was passed called
  AMDUCA (Animal Medicinal Drug Use Clarification
  Act).
• This act gives veterinarians the right to use and
  recommend the use of drugs that are not approved
  for use in sheep.
• (ONLY under certain circumstances)

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AMDUCA

• A valid VCPR exists.
• The health of the animal is at immediate risk and
  suffering or death would result if a drug were
  not used.
• There is not an approved drug on the market for
  that particular condition.
• Accurate records of usage are kept
• Treated animals can be easily identified for an
  extended period.
• An extended withdrawal time is used to assure
  that no illegal residue occurs.

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AMDUCA (cont.)

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

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Recommendations to Producers for Prudent
Antibiotic Use

• Before treatment is given, a diagnosis must be
  made by you, or your veterinarian.
• Use a sheep veterinarian that gives you treatment
  protocols. (preferably written)
• Follow your sheep veterinarians advice and give
  feedback.
• Every time you give an antibiotic understand and
  adhere to the withdrawal time.
• Keep Appropriate Records

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Veterinarians Role in the Sheep Industry

• We must be able to justify ourselves
  economically.
• Medicine on a Flock basis
• QA, Protocols, outbreak treatments, diagnostic
  assistance.
• Prevention of Disease on a Flock basis.
• Biosecurity Protocols, Risk Assessments

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Parasite Control Programs

• Suelee Robbe, DVM, MS
• Diagnostic and Production Animal Medicine, Iowa
  State University

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Typical parasitic lifestyle

• Adults-Hang out in the GI tract
• Abomasum
• Haemonchus , Ostertagia, some Trichostrongylus
• Small intestine
• Trichostrongylus, Nematodirus
• May live for longer than a year, but usually egg
  production peaks 3 months

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Typical parasitic lifestyle

• Eggs
• Development from egg to infective (L3) larvae can
  occur as early as 6 days
• Molt into L1s in the egg then hatch
• Nematodirus develop into L3s in the egg, then
  hatch
• Most ova do not survive very cold ambient
  temperatures

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Typical parasitic lifestyle

• L3s - infective stage
• Thick cuticle protects them from drying
• Cannot feed - finite life span
• Warm temperatures increase their metabolic rate.
• Can survive some freezing

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Typical parasitic lifestyle

• L3s molt in to L4s soon after their ingestion
  where they may rest for a time
• Hypobiosis
• occurs in most species of worms

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Haemonchus

• Adults live in abomasum
• ingest 0.05ml blood/worm/day
• 5000 worms will remove 250 ml of blood.
• Adults are very prolific egg layers
• Haemonchus L3s are not as cold hardy as others
• Most L3s live for 1-3 months

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Others parasites

• Nematodirus
• Ostertagia
• Trichostrongylus
• Plan your parasite program to control haemonchus

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Coccidia

• All sheep shed coccidia
• Clinical signs
• Sudden death
• Scouring lambs
• weight loss

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Prevention

• Keep environment clean and dry
• Design feed and water bunks so lambs cannot step
  in them
• Feed coccidiostats
• Decox
• Bovatec

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Treatment

• Amprolium
• Sulfa drugs

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Parasite control

• Control of L3s on pasture is critical, and is
  related to number of adults in the animal.
• A parasite program that
• Targets L3s controls the parasite burdens in
  grazing sheep.
• Targets L4s and adults in the animal does not
  necessarily control L3s on pasture.

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Example Sheep flock
Working facility/barns
Close Pasture
Remote Pasture
Winter close up pasture.
Moves here in the summer.
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Example Sheep and goat flock
Working facility/barns
Close Pasture
Remote Pasture
Wants to move here Sept. 30 last sheep/goat July
4th
Flock here since June 20 FEC Aug 1st. Dewormed
Dectomax Sept 2
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Example Sheep and goat flock
Working facility/barns
Close Pasture
Remote Pasture
L3 Burden in Oct?
L3 Burden in Sept/Oct?
HIGH
LOW
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Parasite control programs

• Development and survival of infective larvae
  depend on temperature and moisture.
• Optimums vary with worm species.

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Parasite control

• Host Resistance depends on
• Age
• Vigor
• Genetic constitution
• Presence or absence of established parasite
  infections
• Acquired immunity

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Parasite control

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

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Anthelmentics

• Long acting
• ivermectin-larvicidal 10 days
• doramectin -larvicidal 20 days
• eprinomectin
• moxidectin
• Pour-ons do not work in sheep
• Disadvantages Parasite resistance, cost, WDT,
  Not Ovicidal

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Anthelmentics

• Short acting or purge
• levamisole
• relatively poor against immature or arrested L4
  larvae
• Low margin of safety
• benzimidazoles (fenbendazole, oxfendazole,
  albendazole)
• These products are ovicidal

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Host resistance issues

• kids typically more susceptible
• goats producing more milk typically have higher
  parasite burdens
• animals under stress/have pre-existing conditions
  are more likely have higher parasite burdens

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Parasite Resistance

• The best way to avoid resistance to an
  anthelmintic is not to use it.
• If you rely on just anthelmintics as your sole
  parasite control program you WILL get resistance.
  
• There never has been and most likely never will
  be an anthelmintic that wont have resistance
  problems

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