Abortion in sheep

Question 1

What is the average gestation of a sheep?

Answer 1

147 days

Question 2

What is the average lambing survival % of hill, upland and lowland sheep?

Answer 2

Hill - 100%
Upland - 150%
Lowland - 170%

Question 3

What should the ratio of ewe: ram be?

Answer 3

30:1

Question 4

What causes Enzootic Abortion of the Ewe (EAE)?

Answer 4

Chlamydophila abortus
(Gram -ve cocci)

Question 5

How is Chlamydophila abortus spread?

Answer 5

Orally or near lambing time

Aborting ewes main source - carrier ewes less commn

Question 6

What happens if a ewe is exposed to Chlamydophila abortus (EAE) and she has already lambed?

Answer 6

Asymptomatic infection
Latent in repro tract
Activates and causes abortion at next lambing season

Question 7

What happens if a ewe is exposed to Chlamydophila abortus (EAE) when she is <90 days pregnant?

Answer 7

May abort, OR become latently infected (abortion at next lambing season)

Question 8

What happens if a ewe is exposed to Chlamydophila abortus (EAE) when she is >90 days pregnant?

Answer 8

May abort

Question 9

How does an outbreak of Chlamydophila in a flock affect that years lambing abortions and the following years?

Answer 9

That year - low levels of abortion
Following year - high levels >30%
Endemically infected flocks 5-10%

Question 10

When do ewes tend to about with Chlamydophila abortus (EAE)?

Answer 10

> 90 days

Usually last month

Question 11

Do ewes themselves get ill from Chlamydophila abortus (EAE)?

Answer 11

Rarely - may get metritis which can be fatal

Question 12

How is Chlamydophila abortus diagnosed?

Answer 12

PCR
Serology of ewe
PME - necrotic placentitis

Question 13

How can an outbreak of Chlamydophila be controlled?

Answer 13

Burn all abortion material and bedding, clean and disinfect pens, isolate aborted ewes
Treat remainder of flock with vaccine (non-pregnant), or pregnant ewes >90d with oxytetracycline (repeat in 2 weeks)
Vaccinate all ewes following year pre-tupping

Question 14

How can Chlamydophila abortus be prevented?

Answer 14

Vaccination (doesn’t prevent if already latent infection - will still abort next year)
Biosecurity - breed own replacements, don’t buy in

Question 15

What species are the definitive and intermediate hosts for Toxoplasma gondii?

Answer 15

Definitive: cats
Intermediate: sheep

Question 16

Toxoplasma is zoonotic. How can people get Toxoplasma?

Answer 16

Undercooked meat
Raw sheep milk
Cat faeces
Lambing with skin wounds

Question 17

If a ewe is infected with toxoplasma and she is not pregnant, what happens?

Answer 17

Few clinical signs

Becomes immune

Question 18

If a ewe is infected with toxoplasma in early pregnancy, what happens?

Answer 18

Foetal resorption - presents as barren ewe

Question 19

If a ewe is infected with toxoplasma and she is in mid pregnancy, what may happen?

Answer 19

Foetal death, retardation or mummification

Question 20

If a ewe is infected with toxoplasma and she is infected in late pregnancy, what may happen?

Answer 20

Aborts freshly dead lambs
Or weak lambs with high mortality rate
Or live and immune lambs

Question 21

When do ewes develop immunity to Toxoplasma?

Answer 21

If infected whilst not pregnant (already given birth)

Aborted ewes become immune

Question 22

How is Toxoplasma diagnosed?

Answer 22

Serology - Toxoplasma antigen in placenta
PCR or serology
‘Frosted strawberry cotyledons on PME’

Question 23

How can Toxoplasma be prevented?

Answer 23

Control cat and rodent population, secure feed stores

Vaccinate with toxovax weeks prior to tupping (not to be used in pregnant ewes)

Question 24

Salmonella abortus ovis causes abortion in which trimester of pregnancy?

Answer 24

Last trimester

followed by metritis

Question 25

What antibiotic is used to treat Salmonella abortus ovis?

Answer 25

Oxytetracycline - repeat after 7-10 days

Question 26

Give examples of the sources of Campylobacter

Answer 26

``` Carrier sheep Contaminated feed/water Aborted material Birds (Very contagious - can cause abortion storms) ```

Question 27

When does Campylobacter abortion occur? Does it always cause abortion?

Answer 27

Last 6 weeks of pregnancy | No- can cause weak born lambs

Question 28

Is there a vaccine for Campylobacter?

Answer 28

No

Question 29

Is Campylobacter zoonotic?

Answer 29

Yes

Question 30

What type of virus causes BVD and how is it introduced into the flock?

Answer 30

Pestivirus | PI animals - introduce and maintain BV

Question 31

What happens if a non-pregnant ewe is infected with Border disease?

Answer 31

No clinical signs | Immune

Question 32

What happens if a ewe is infected with Border disease <60 days pregnant?

Answer 32

50% foetal death or absorption

Question 33

What happens if a ewe is infected with border disease 60-85 days pregant?

Answer 33

Foetal, death or abortion OR hairy shaker (weak) lambs OR PI lambs

Question 34

What happens if a ewe is infected with border disease 85+ days pregnant?

Answer 34

Lamb and ewe immune

Question 35

How is Border disease controlled if in the flock?

Answer 35

Do not breed from entire lamb crop | Test whole flock for PI and cull

Question 36

How can Border disease be prevented?

Answer 36

Closed herd | Test buy in sheep for PI

Question 37

Listeria monocytogenes causes encephalitis, septicaemia and abortion. How long after feeding contaminated or mouldy sheep do they abort?

Answer 37

1-2 weeks after feeding

Question 38

What is the treatment for Listeria monocytogenes?

Answer 38

Remove contaminated feet | Antibiotics for all in contact - penicillin, oxytetracycline

Question 39

What pathogen causes tickborne fever?

Answer 39

Anaplasma phagocytophilia | Affects WBCs

Question 40

How is tickborne fever prevented?

Answer 40

Avoid introducing naive sheep when pregnant or at tupping time Treat sheep with pyrethroid pour on before entering tick areas

Question 41

How is Coxiella burnetti (Q-fever) controlled?

Answer 41

Isolate infected animals Burn contaminated material Oxytetracycline Pasteurise milk

Question 42

Sheep and cows with Schmallenberg may have no clinical signs or increased barren ewe rate. A foetus can only be infected between how many days pregnancy?

Answer 42

26-56

Question 43

How is Schmallenberg spread?

Answer 43

``` Culicoides midges (delay breeding until midge season over) ```

Question 44

Can Schmallenberg lambs be born alive?

Answer 44

Yes - may be 'dummy' | Blind, wobbly, unable to suck, fitting

Question 45

How are lambs tested for Border disease on PME?

Answer 45

PCR of spleen

Question 46

How are lambs tested fro Schmallenberg on PME?

Answer 46

PCR of brain