2/3: Pregnancy failure and abortion Flashcards
What % of ewes conceive after each mating?
90%
What % of ewe lambs conceive after each mating?
50%
What is the most common cause of reduced conception rates, infectious or otherwise?
Nutrition (BCS at tupping)
What day do you scan ewes for barren or number?
70
With what % accuracy can you identify barren ewes at 70 days?
100%
With what % accuracy can you identify number of lambs at 70 days?
90-95%
What is the advantage of knowing the number of lambs?
Can feed to litter
How do you see early pregnancy failure?
Increased barren rate
Why should you always investigate a single case of abortion in a bought-in ewe?
Due to EAE risk
Which abortion cases should you always investigate?
Single case of a bought-in ewe, multiple cases (over 2%), cluster of abortions
What hormones mediate stress-induced abortions in sheep vs goats?
Cortisol in sheep, PGs in goats
What are two reasons a larger litter size can increase pregnancy failure?
Placental insufficiency or toxaemia
At what point of pregnancy are more infection outbreaks?
The month before lambing
Which animals may the endemic infections be confined to?
Younger
Which lesions will show up in the placenta?
Toxoplasma, EAE, Q fever
Which lesions will show up in the foetus?
Toxoplasma, border disease, Listeria
In which infections is the ewe also ill?
Salmonella or Q fever
What is the most common cause of ovine abortion?
EAE
What causes EAE?
Chlamydia abortus
Is EAE zoonotic?
Yes
What can lambs be like in EAE?
Aborted, premature, weak live, or normal with infected membranes
What can happen to the ewe following EAE?
Retained membranes so metritis
What is a consequence of the ability of EAE to evade the immune response?
Low grade asymptomatic infection
What is the life cycle of EAE?
Specialised - intra and extracellular phase
What are the two sources of EAE?
Infected purchase (80%), or wildlife
How long can EAE particles survive?
Weeks at low temps
How is EAE spread from sheep to sheep?
Inhalation or ingestion
What will happen if infected with EAE early in pregnancy?
Abort
What will happen if infected with EAE later in pregnancy?
Reactivates from the latent stage during the NEXT pregnancy
What happens to the lambs that are born from an EAE-infected pregnancy?
30% of these will get placentitis or abort in their own first pregnancy
How can you detect ewes/lambs infected with the latent stage?
Cannot
How do the lambs get infected with EAE?
Uterine discharge on teats, NOT milk
What are the signs a ewe is going to abort from EAE?
No signs, but some have vaginal discharge
What does the placenta look like in EAE?
Inflamed, thickened, necrosed, placentitis
What do aborted lambs look like in EAE?
Normal, not mummified
Where do you take smears from in EAE?
Affected cotyledons
Where do you take serology from in EAE?
Dam and foetal fluid
How do antibiotics help in EAE?
Reduce shedding but abortion will occur despite treatment
Which antibiotics do you give in EAE?
Long acting tetracycling
At what stage of pregnancy do you give antibiotics in EAE?
95-100 days until lambing
What should you do following an EAE outbreak?
Isolate, burn dead, don’t foster, only buy from EAE accredited flocks, consider vaccination
When do you give ENZOVAC for EAE?
Live so can’t give when pregnant - so 1-4 months pre-tupping
How long does ENZOVAC last?
Two years, but do yearly if high risk and not an accredited flocks
What is the second most common cause of abortion?
Toxoplasma
What can the lambs look like in toxoplasma?
Aborted, still birth, live but weak
What is toxoplasma like in the ewe or non-pregnant sheep?
Mild - a disease of the conceptus
How long can toxoplasma oocysts survive on pasture?
Two years
How many toxoplasma oocysts are needed to infect a ewe?
200
What happens if a ewe gets toxoplasma after 120 days?
Stillborn, weak or normal lambs
What happens if a ewe gets toxoplasma at mid-gestation?
Aborts or mummifies
What happens if a ewe gets toxoplasma early (before 60-70 days)?
Resorbs and returns to oestrus
What does the placenta look like in toxoplasma?
Cotyledons bright red with small white nodules
Other than the placenta, what are the other ways to confirm toxoplasma?
Staning, histo, serology
How do you treat Toxoplasma?
Monensin, decoquinate, TMPS
How does toxoplasma spread from ewe to ewe?
No lateral spread
What should you do with the ewes that have aborted?
Retain them as they are immune
What is an advantage of old neutered cats in controlling toxoplasma?
Reduce vermin and keep feral cats away
How long does toxoplasma take to cause a febrile response?
5-12 days
How long does toxoplasma take to reach uterine caruncles?
10 days
How long does toxoplasma take to reach foetal antibodies?
30 days
Why should you expose new additions to the flock outside pregnancy to toxoplasma oocysts?
Infection outside pregnancy produces good immunity
When do you vaccinate ewe lambs for toxoplasma?
5 months
When do you vaccinate ewes for toxoplasma?
4 months before tupping
When do you vaccinate pregnant ewes for toxoplasma?
Don’t
How long does toxoplasma vaccine protection last?
18 months
What are two iatrogenic causes of abortion?
Steroids in late pregnancy, PGF2a any time in sheep
What are two toxins that can cause abortion?
Heavy metals, careless dip disposal
At what stage of pregnancy can manganese cause abortion?
80-100 days
Which concurrent diseases can cause abortion in sheep?
Tick borne fever, or liver fluke
What condition in Angora goats can cause abortion?
Hyperadrenocorticism
What is the third most common cause of abortion in sheep?
Campylobacter
Which species cause Campylobacter in sheep?
C fetus and C jejuni
How does a symptomless carrier spread Campylobacter?
Excretes in faeces, then ingested
How does Campylobacter spread from an affected sheep?
Aborts, then lateral spread to susceptible ewes
In which conditions can Campylobacter survive?
Cold and moist
At what part of pregnancy do sheep usually abort from Campylobacter?
Last 6 weeks
What are lambs born in Campylobacter like?
May be stillborn or weak
What are some signs of Campylobacter in the ewe?
Vulval swelling and reddish discharge
What may the ewes gets after abortion in Campylobacter?
Metritis
Is the aborted material also infected in Campylobacter?
Yes
What happens if infected with Campylobacter before 3 months?
Not affected
What happens if infected with Campylobacter after 3 months?
Bacteraemia, placentitis, then abort 1-3 weeks later
What % abortion can you get in a flock following first-time Campylobacter infection?
5-50%
How long does immunity to Campylobacter last?
Strong, serotype specific immunity for 3 years
How long can symptomless carriers excrete Campylobacter?
18 months
What does the placenta look like in Campylobacter?
Oedema and necrosis of cotyledons
What does the foetus look like in Campylobacter?
Fresh - but characteristic necrotic 1-2cm foci in the liver
Which age ewes in Campylobacter most common in?
Young, or old ones which have lost immunity
What can you stain to diagnose Campylobacter?
Placenta or foetal stomach contents
Where can you culture Campylobacter from?
Placenta, foetal stomach contents or liver
How useful is serology in Campylobacter?
Unhelpful
What should you do if you suspect Campylobacter?
Isolate, and give antibiotics if extensive lateral spread
How can you stimulate immunity to Campylobacter in the flock?
Mix aborted ewes with those already lambed
What are some ways to prevent Campylobacter in the flock?
Prevent birds getting to troughs, keep flock closed, mix brought-in sheep with residents for immunity, then separate in late pregnancy
Is there a vaccine for Campylobacter?
No
Which Salmonella serotypes cause abortion?
Abortusovis, typhimurium, dublin, montevideo
How can you get exotic strains of Salmonella?
If fed on imported protein
How do ewes contract Salmonella?
Many sources - ingest contaminated food and water
What happens if infected with Salmonella in early pregnancy?
May be barren
What happens if infected with Salmonella in late pregnancy?
Aborted, stillborn or weak lambs
What are affected ewes like in Salmonella?
Often ill - catastrophic losses
What can happen to ewes that recover from Salmonella?
Symptomless carriers
What are systemic signs like in S abortus or montevideo?
Few
What stage of pregnancy does abortion occur in S abortus?
Last 6 weeks
In which Salmonella species are symptomless carriers a problem?
S abortus
What do lambs look like following S abortusovis?
Either born weak and die in a few hours, or born healthy and die in the first ten days
Where is S montevideo a problem?
SE Scotland
Which Salmonella species could become endemic?
Montevideo
Which Salmonella species may involve seabirds?
montevideo
What is severity of montevideo like compared to typhimurium or dublin?
Less
Do lambs born alive in montevideo have diarrhoea?
No
What precedes S typhimurium disease?
Stress
What are ewes like in S typhirmurium?
Anorxia, pyrexia above 41, scour, foul vaginal discharge, tehn die from septicaemia or dehydration in 6-9 days
What are lambs like in S typhirmurium?
Born dead, but if alive have severe illness and high mortality
Is S dublin or typhimurium more severe?
Typhimurium
Which is the only Salmonella that is not zoonotic?
Abortusovis
What are some signs a ewe had Salmonella?
Scouring, pyrexic, foul vaginal discharge
What do labs born alive with salmonella die of?
Septicaemia or pneumonia
What can you culture to diagnose Salmonella?
Foetal stomach contents, placental tissue, vaginal discharge
Other than culture, what are other ways of diagnosing Salmonella?
Fluorescent antibody test, or serology for S abortusovis
What is the persistent reservoir of Salmonella?
Symptomless carriers
What should you ideally send for sampling following abortion?
Placenta and foetus
How do you treat Salmonella?
Isolate sheep, give antibiotics based on sensitivity if aborted or scoured
How do you avoid Salmonella outbreaks in sheep?
Avoid stress, avoid wild birds, avoid competition for feed, use piped fresh water
What % of abortions does listeria account for?
2%
Which listeria species cause abortion?
Monocytogenes or ivanovii
What are some signs of a listeria infection?
Encephalitis, abortion, diarrhoea, septicaemia, KCS, mastitis, death (in young lambs)
What is the most likely source of a listeria infection?
Soil, esp silage, but sheep require other factors to cause disease
What happens if infected with listeria in late pregnancy?
Infects foetus, get septicaemia and placentitis, foetal death and abortion
Which stage does abortion normally occur in in Listeria?
Can be any stage, but usually late pregnancy
What is a distinguishing feature of listeria?
None
What do lambs look like following Listeria?
Weak, with white focal necrosis of the liver
What can the foetus look like following Listeria abortion?
May be autolysed
What does the placenta look like in Listeria?
Necrotic placental villi, chorion covered in brown-red exudate
What is vaginal discharge like in Listeria?
Heavy, brown
Where can you culture listeria from?
Vaginal swab, foetal membranes, foetal liver lesions, fluorecent antibody
When do you give antibiotics in Listeria?
If aborted or discharging
How do you prevent Listeria?
Isolate all aborted ewes and don’t give poor silage to pregnant animals
What are some signs of Border disease?
Neuro signs, tremor, course fleece, reproductive failure
What causes Border disease?
A pestivirus, similar to BVD
What signs does border disease give in lambs?
“Hairy shaker”
What signs does border disease give in adults?
Mild pyrexia
What does the foetus look like in border disease?
Mummified, absorbed or resorbed, or lambs born weak
At what stage of pregnancy is abortion most common in border disease?
90 days (mummified or anasarcous)
At what stage of pregnancy is the conceptus most susceptible to border disease?
16-80 days
What are some ways of diagnosing border disease?
Clinical signs, histopathology of CNS, virus isolation, fluorecent antibody test, serology on barren or aborted ewes
How is border disease spread?
PI animals
How do you treat border disease?
Can’t
Can you vaccinate for border disease?
No
How can you prevent border disease?
Keep closed flock, segregate from affected ewes, ensure non-pregnant develop immunity, don’t retain exposed lambs
What stage of gestation does leptospirosis normally affect?
Late
Which periods of life does leptospirosis affect?
Immune compromised - 2 weeks before lambing, and 1st week of life
Which kind of flocks get leptospirosis?
Intensively housed lowland flocks
How can you prevent leptospirosis?
Minimise contact between cattle and sheep, vaccinate before tupping with 1/4 cattle dose
What do you see in adult ewes that get lepto?
Late abortion, still birth, weak lambs
What do you see in lambs that get lepto?
Meningitis
How do you diagnose leptospirosis?
Isolated from aborted foetus or membrane or paired serology from a rising titre
What do the foetal tissues and placenta look like in lepto?
See fat
How do you treat lepto?
Dihydrostreptomycin during abortion storm
What causes Q fever?
Coxiella burnetti
What is the significance of Q fever in sheep farming?
Little - a public health issue
How does Q fever spread?
At parturition, as placenta and vaginal discharge are heavily contaminated, or aerosol from fleece or dust
In which ewes can you isolate Ureaplasma from?
Those with granular vulvitis
How is Ureaplasma distributed?
By ram
What does Ureaplasma cause in cattle?
Infertility and abortion
Which areas of the country get tick-borne fever?
Where Ixodes ricinus occurs
What happens following tick borne fever infection in late pregnancy?
Fever, then abort 2-8 days later, then mummified and expulsed weeks later
What happens following tick borne fever if not pregnant?
Uneventful recovery
What happens to rams exposed to tick borne fever?
Reduced fertility for several months
What is the infectious agent in tick borne fever?
Cytoecetes phagocytophilia
Which cells is tick borne fever found in?
In leucocytes of aborted or septicaemic ewes
How do you treat tick borne fever in a naive flock?
Oxytetracycline
What happens to ewes that survive tick borne fever?
Immune, usually from an early age
How do you control ticks?
By dipping
When do you introduce new sheep to the flock to prevent tick borne fever?
Before tupping
What kind of a virus causes Schmallenberg?
Simba serogroup of Orthobunyaviruses
How is Schmallenberg spread?
Culicoides midges
What is the only way Schmallenberg spreads from animal to animal?
Transplacental from viraemic dam to foetus
What do lambs look like in Schmallenberg?
Aborted, stillborn, congential defects or limbs and skull
What tests do you do if you suspect Schmallenberg?
Histopath, serology, ELISA
How can you prevent Schmallenberg?
Vaccine available, control insects, serology to assess exposure
What are immediate steps following abortion outbreak?
Isolate, disinfect area, destroy bedding, no fostering or milk use, separate those still to lamb, antibiotics if ill, plan future prevention
What is the most likely cause of abortion if below 2 years?
Toxoplasma
What is the most likely cause of abortion if above 2 years?
Chlamydia
What is prevalence of pseudopregnancy is goats?
5-30%
What usually precedes pseudopregnancy in goats?
Normal oestrus or foetal death
Which goats have increased risk of pseudopregnancy?
Older goat, goatling, artifical breeding
Is pseudopregnancy recurrence likely?
Yes
How is pseudopregnancy inherited?
Familial
From which stage of pregnancy can you diagnose pseudopregnancy by ultrasound?
50-100 days
From which stage of pregnancy can you diagnose pseudopregnancy by milk or plasma oestrone sulphate?
45 days
From which stage of pregnancy can you diagnose pseudopregnancy by radiography?
80-100 days
How do you treat pseudopregnancy?
PGF2a, and repeat 10-12 days later to prevent recurrence
Why might oxytocin help when treating pseudopregnancy?
May aid involution
What are infectious abortion causes in goats?
The same as sheep
What are two particular causes of non-infectious abortion in goats?
Stress, and placental insufficiency
What are two particular causes of non-infectious abortion in Angora goats?
Environmental stress and chronic energy deficiency
Which Angora goats especially abort?
Young, poorly grown goats at 90-120 days gestation
Why can larger goats especially get habitual abortion?
Due to hyperfunction of adrenal glands
