Sheep abortion

Question 1

What factors in the RAM affect fertility (scanning %)?

Answer 1

Health (lameness, age, chronic disease)
Nutritional status (BCS 3.5-4)
Numbers
Reproductive function (sperm count, sperm motility, sperm viability).

Question 2

What factors in the EWES affect fertility (scanning %)?

Answer 2

Age

Time of year (Seasonal breeders)

Nutrition (BCS) - cycling, ovulation rate, quality of eggs, placental development, energy protein nutrition trace elements.

Disease - lameness, fluke, wasting disease.

Infectious abortion.

Question 3

What is the gestation of a ewe?

Answer 3

147 days (range 140-150 days) = 4.8 months

Question 4

What are the 3 types of abortion causes?

Answer 4

Infectious
Mixed infections
Non infectious (stress, handling)

Question 5

What level of abortion in a flock indicates a problem?

Answer 5

<2%

Question 6

What is the biggest cause of infectious abortion?

Answer 6

chlamydophilia abortus

Question 7

Give 4 major causes of abortion?

Answer 7

chlamydia
Toxoplasma
salmonella
Campylobacter

Question 8

Give 9 other causes

Answer 8

Border disease
E coli
Listeria monocytogenes
Tickborne fever
Coxiella burnetti (Q fever)
Yersinia spp. 
Fungi
Arcanobacterium pyogenes
Bluetongue

Question 9

Is chlamydia abortus zoonotic?

Answer 9

Yes - pregnant women, immunocompromised individuals.

Question 10

What is chlamydia abortus?

Answer 10

Bacterium

Question 11

is chlamydia abortus gram +ve or -ve? what morphology does it have?

Answer 11

Gram negative cocci.

Question 12

How is chlamydia abortus transmitted?

Answer 12

ORAL route of infection

- discharge products of abortion heavily contaminated.

Question 13

What is the main source of infection of chlamydia abortus in a NAIVE flock?

Answer 13

– Aborting ewes- main source
• Discharges products of abortion heavily
contaminated, viable for several days
– Carrier ewes –less common
• May or may not abort
• shedding at lambing, some spread at oestrus.

Question 14

If a ewe becomes infected whilst pregnant with chlamydia, what are the possible outcomes of exposure?

Answer 14

1) if ewe more than 90 days pregnant, she may abort.
2) If less than 90 days pregnant she may:
- abort after 90 days pregnancy.
- or she may become latently
infected by harbouring agent
in reproductive tract and
abort at next pregnancy

Question 15

If ewe becomes infected with chlamydia whilst NOT pregnant e.g. after lambing or tupping time, what is the outcome of exposure?

Answer 15

1. Latently infected harbouring
   infection in reproductive tract and
   abort at the following lambing

Question 16

What is the outcome of ewe lambs becoming infected with chlamydophila abortus?

Answer 16

Ewe lambs born to infected ewes can become infected and

abort in first lambing

Question 17

Do the ewes become immune post chlamydophila infection?

Answer 17

Once aborted most ewes
become immune and not
abort again, but some will
become carriers and shed at
oestrus and lambing