Abortion and Perinatal Mortality in Sheep

Question 1

Major differentials of infectious ovine abortion.

Answer 1

Chlamydophila.
Toxoplasma.
Campylobacter.
Salmonella.
Listeriosis.
Border disease.
Q fever (coxiella burnetti).
Leptospirosis.

Question 2

1. Epidemiology of infectious abortions in sheep.
2. How can horizontal spread of infection be limited at lambing season? – considerations.

Answer 2

1. If contracted by non-pregnant ewe, no disease.
   If contracted by pregnant ewe, abortion.
2. V good hygiene.
   – Lambing pens can be difficult to keep hygienic with time pressure on staff.

Question 3

1. Campylobacter spp that cause abortion in sheep. – and percentages of campylobacter abortions each cause?

Answer 3

1. C. foetus subsp. foetus. – 90%.
   C. jejuni. – 10%.

Question 4

Clinical signs of campylobacter abortion.

Answer 4

Rarely signs in the ewe.
Abortion any time in last 3 months of gestation.
May see liver lesions/swollen liver in foetus.

Question 5

Campylobacter abortion epidemiology.

Answer 5

Campylobacter foetus subsp. foetus is found in gut of carrier sheep and spreads horizontally at lambing.
Campylobacter jejuni found in most birds.
Contamination if water/fields/paddocks.
Horizontal spread between sheep.

Question 6

Diagnosis of campylobacter abortion.

Answer 6

Culture from foetal stomach (and liver/placenta).
Specialist media and conditions.

Question 7

Treatment of campylobacter abortion.

Answer 7

Use of ABX in the face of outbreak.
Oxytetracycline.
Pen/Strep.
No vaccines available in UK.

Question 8

1. What is Border Disease?
2. Border Disease clinical signs?

Answer 8

1. Pestivirus (related to BVD and CSF).
   Originally reported in Welsh/English borders.
2. Foetal resorption.
   Abortion.
   Hairy-shaker lambs (persistently infected with the virus).
   Normal lambs.

Question 9

1. What if Border Disease contracted between conception and 60d gestation?
2. What is Border Disease contracted between 85d gestation and birth?

Answer 9

1. Foetal death, resorption, mummification, abortion, stillbirth or hairy-shaker lambs, weak or normal lambs, no antibodies detectable.
2. Foetal death, abortion, stillbirth or foetal survival, weak or normal lambs w/ antibodies to Border Disease, no virus detectable.

Question 10

Hairy-Shaker lambs.

Answer 10

• Small and weak.
• Nervous signs from tremors to violent shaking.
• Fleece changes in smooth coated breeds.
• Skeletal abnormalities.

Question 11

1. Clinical signs of Border disease?
2. Border Disease epidemiology.

Answer 11

1. Usually only signs in pregnant ewes.
   Rarely see disease in non-pregnant sheep.
2. Mainly sheep to sheep transmission by persistent carriers and also in semen.
   Can get BD from BVD in cattle or other ruminant pestiviruses.

Question 12

Diagnosis of BD?

Answer 12

Abortions/stillbirths.
Hairy-Shakers.
Demonstrate virus in fresh tissues (specific immunostaining).
Can test a 10% sample of the flock for antibodies to demonstrate presence and the extent of BD virus infection in the flock.

Question 13

Border Disease control.

Answer 13

Depends on extent of infection in flock:
- if sporadic outbreak, entire lamb crop should go for slaughter (don’t keep any replacements) and cull sheep suspected of introducing disease (if known).
- if endemically infected, deliberately expose breeding animals when not pregnant to known persistently infected lambs (house indoors for at least 3wks). End exposure 2mths before start of breeding season.
- if BDV or abortion free flock, test bought-in replacements for ab.
– principle that bought-in ewes should not lamb w/ rest of flock.

Question 14

Salmonella serotypes that cause abortion. – and how they are contracted.

Answer 14

S. montevideo. – food, water, other animals.
S. typhimurium. – food, water, other animals.
S. dublin. – food, water, other animals.
S. abortus ovis – carrier sheep.

Question 15

1. Signs of S. typhimurium and S. dublin.
2. Signs of S. abortus ovis.

Answer 15

1. Enteric and systemic signs predominate along w/ abortion. ‘
2. Late abortion / high lamb mortality.
   Non-specific clinical signs and lesions.

Question 16

Epidemiology of S. abortus ovis abortion.

Answer 16

Carriers are asymptomatic.
Non pregnant sheep experience stress and excrete S. abortus ovis in faeces.
Pregnant sheep experience stress and excrete S. abortus ovis in abortion products.

Question 17

1. Treatment of S. abortus ovis.
2. S. abortus ovis control.

Answer 17

1. ABX in face of outbreak.
   - Long-acting preparations.
   - Antibiotic sensitivity.
   - Supportive treatment.
2. InMEva - Combined (killed) Chlamydophila and S. abortus vaccine.

Question 18

1. Spp. of listeria that cause abortion.
2. Signs of listeria abortion?

Answer 18

1. L. monocytogenes.
   L. ivanovii.
2. Abortion an any stage of pregnancy, may also see other signs w/in the flock:
   - Septicaemia.
   - Encephalitis.

Question 19

1. Epidemiology of listeriosis.
2. Control of listeriosis.

Answer 19

1. Sporadic cases occur.
   Large outbreaks inevitably associated w/ silage feeding of house ewes.
2. Remove silage.
   ABX may reduce losses.

Question 20

1. How common is lepto in sheep.
2. What lepto spp. cause cause ovine abortion?
3. How is the organism excreted?
4. Transmission of lepto.
5. ctrl?

Answer 20

1. Rare - can occur in intensively housed conditions.
2. L. hardjo.
3. In urine.
4. Sheep to sheep. And sheep can act as reservoir of infection for cattle.
5. Could potentially use cattle vaccine in sheep.

Question 21

Coxiella burnetti.

Answer 21

Q Fever.
Modified Ziehl Neelson technique (staining).
Complement fixation test for antibodies.
Zoonotic.
Mostly seen in goats.

Question 22

1. Transmission and spread of Schmallenberg virus.
2. Spp. affected.
3. What does Schmallenberg virus cause?
4. Zoonotic?
5. What is the advice now?

Answer 22

1. Vector borne - midges and ticks.
2. Cattle, sheep, goats.
3. Late abortion or birth defects in new born cattle, sheep and goats.
4. Unlikely.
5. Encouraging farmers to submit lambs/calves w/ arthrogryposis for testing.

Question 23

1. Why does vaginal prolapse occur in pregnancy.
2. When does vaginal prolapse occur?
3. Vaginal prolapse progression.

Answer 23

1. Hormones of pregnancy alter amount and distribution of collagen and smooth muscles in the vaginal wall.
2. Usually 3wks before lambing.
3. Development over a few days.
   Will often return spontaneously when animals rise.
   Eventually fails to return, get further eversion until cervix visible.

Question 24

1. Risk associated w/ vaginal prolapse?
2. Progression of vaginal prolapse to vaginal rupture?

Answer 24

1. Vulnerable to injury.
   Signs of swelling, oedema and congestion ultimately progress to haemorrhage and gangrene.
2. • Neglect prolapse&raquo_space; vaginal damage&raquo_space; straining&raquo_space; vaginal rupture.
     - Prolapse causes urethral obstruction&raquo_space; bladder distension&raquo_space; straining&raquo_space; vaginal rupture.

Question 25

1. How common is vaginal rupture?
2. How does rupture lead to death?

Answer 25

1. Uncommon.
2. Rupture&raquo_space; herniation of caecum ileum colon&raquo_space; death from haemorrhage and shock.

Question 26

1. Breeds predisposed to vaginal prolapse.
2. Relationship between risk of prolapse and litter size.
3. Relationship between age and risk of prolapse.
4. What management factor increases risk of prolapse?

Answer 26

1. Lowland breeds more than hill breeds.
2. Larger litter increases risk.
3. Older ewe increases risk (due to increasing litter size).
4. Overfeeding in flocks managed as a single group or fed on an unrestricted basis.

Question 27

Vaginal prolapse treatment.

Answer 27

Assessment:
- Condition of ewe.
- Condition of vagina.
- Chick if foetal membranes present if cervix open.
Euth. may be necessary for some cases.
Consider use of caudal epidural if straining severe (lidocaine/xylazine for prolonged anaesthesia).
Replacement:
- Lift prolapse and empty bladder.
- Clean up prolapsed tissues v thoroughly.
- Raise rear end of ewe.
- Reduce prolapse carefully.
– tissues may be friable so be careful.
- Farmers use harnesses or plastic retainers (risk metritis and persistent straining).
- Vets use SC purse string suture around vulva or horizontal mattress sutures.
– braided nylon tape.
– stitches into perineal skin, NOT vaginal mucous membrane (get urine scalding and bacterial infection).
Supportive treatment:
- ABX.
- Anti-inflammatory analgesics (Flunixin).
- Check pregnancy toxicity, hypocalcaemia.

Question 28

1. Control of vaginal prolapse.
2. When does uterine prolapse occur?
3. Treatment?

Answer 28

1. Mark ewes w/ prolapse and cull post lambing as 40% will prolapse again.
2. Post lambing.
3. Replace as for prolapsed vagina.