Fertility problems and Abortion Flashcards
Name 4 general causes of sub-optimal reproductive performance in sheep
1) Anestrus / low ovulation rate
2) fertilization failure
3) embryonic loss / early fetal death
4) late fetal loss (abortion/preg tox)
Name 3 common causes of poor ram breeding soundness
1) Testicular degeneration / hypoplasia
2) epididymitis
3) scrotal trauma
Causes of epididymitis in the UK
gram negative pleomoprhic bacteria (actinobacillus seminis, hemophilus somnus, histophilus ovis)
ascending urogenital infections
CS epididymitis
Palpable abnormalities (firm nodules in epididymis; testicular atrophy) on routine breeding soundness exam
+/- swelling, pain, lameness, inapettance during acute infections
Epididymitis Tx
Cull
What is normal gestation length?
~147 days (142-150)
Target abortion percentage?
<2%
Name a viral cause of abortion in sheep
Border disease virus
Name 2 protozoan causes of abortion in sheep
Toxoplasma gondii, neospora caninum
What are the 2 most commonly diagnosed causes of ovine abortion?
Toxoplasma gondii and Chlamydophila abortus
Name 5 bacterial causes of abortion in sheep
Chlamydophila abortus (enzootic abortion) campylobacter species salmonella leptospira iterrogans listeria monocytogenes
Name some non-infectious causes of abortion in sheep (8)
nutrition, pregnancy toxemia, stress, vaccination, transport, dog worry, pasteurellosis, chronic fluke
What is the best type of sample to submit to investigate abortion problems?
whole fetus / placenta
What are 5 measures that should be taken after an abortion (but before confirmation of cause is found)?
1) Isolation and marking of aborted ewes
2) prompt disposal of products of abortion
3) biosecurity to avoid spread
4) hygienic precautions to minimize zoonoses
5) reduced stocking density or pregnant lambing ewes (if practical)
CS of chlamydial abortion?
in last 3 weeks of pregnancy, healthy ewes, reddish vaginal discharge, lambs freshly dead or alive (but weak and unable to suckle)
Dx of chlamydial abortion?
Placentitis - discoloration/ necrosis of cotyledons, edema/rough thickening of intercotyledonary membranes, yellow/pink pus-like exudate
demonstration of large # of chlamydial elementary bodies in ZN stained smears of placental tissue
or paired serology if no aborted material
What are the outcomes of chlamydial infection for:
1) Late pregnant/non-pregnant ewes?
2) ewe in first half of pregnancy?
3) surviving lamb from infected ewe?
1) no immune response, abortion during last 3 weeks of NEXT pregnancy
2) abortion during last 3 weeks of CURRENT pregnancy
3) abortion during it’s first pregnancy
Control of chlamydial abortions?
isolate aborted ewes + surviving lambs (cull)
remove products of abortion and contaminated bedding
Abx tx of whole flock or in-contact ewes (oxytet)
vaccination
Chlamydial vaccination: what kind, when, result?
Live attenuated vaccines
vaccinate all ewes in first ear; then replacment ewes/gimmers before mating
in outbreak, may reduce but not eliminate the risk of abortion in following year
CS of toxoplasma abortions? (early, mid, late pregnancy)
Early pregnancy = embryonic death / resorption (barren ewes)
mid-pregnancy = fetal death (mummification); fetal growth retardation
Late pregnancy = freshly dead lambs; weak live lambs
Dx of Toxoplasma
Aborted material gross findings: placenta (hyperemic cotyledons, small white foci of necrosis & calcification), lamb (SQ edema; fibrinous exudate in pleural & peritoneal cavities)
Confirmation = histo and serology
Serology in aborted ewes w/ toxo: what do high and low titers mean?
High titers = usually consistent w/ recent infection
Low titers = only indicate infection @ some stage in the past - Ab can persist for several years
Tx and control of toxoplasma
Rodent control, keep feed stores safe from cats, limit cat breeding
Decoquinate - 2mg/kg SID (last 2 weeks of pregnancy)
Vaccination (toxovax) - live vx, single dose 3 weeks before mating
How long after infection w/ campylobacter will the ewe abort?
7-25 days after
What are sources of infection for campylobacter and how is it transmitted?
Sources = carrier ewes, wild birds, infected clothing/equipment
Transmission = direct w/ aborted material, vaginal discharges (up to 6 wks after abortion), contaminated environment (bacteria survive up to 3 weeks), NO venereal transmission (vs. cattle)
CS of campylobacter infections
Late abortions - last 6 weeks of pregnancy
ewes - blood stained or purulent vaginal discharge, no systemic signs
placenta - inflamed, edematous, may be covered by thick yellow-white exudate
aborted fetuses - fresh, may contain serosanguinous exudate in body cavities
Dx campylobacter infection
smears from placenta or fetal stomach
ZN or gram stain
Tx & control of campylobacter
Isolation of aborted ewes
tx w/ broad spectrum abx
reduce environmental challenges
Vaccination in USA (not UK)
aborted ewes = immune, become carriers
3 serotypes of salmonella commonly seen in UK sheep abortions
montevideo, typhimurium, dublin
CS of salmonella montevideo (most common in sheep per professor)
abort through 2nd half pregnancy, lambs fresh or autolysed
ewes normal
CS of salmonella dublin
Infection via carrier cattle
systemic illness & diarrhea more frequent in ewes
Treatment and control of salmonellosis
S. montevideo = whole flock tx with long acting oxytetracycline
how long after infection does abortion occur?
several weeks later - (has already had time to spread w/in the group)
What kind of disease is border disease?
Pestivirus
closely related to BVDV
Dx of border disease
pestivirus antigen in fetal/lamb blood & tissues
Serology - ewes; aborted fetus
control of border disease
difficult
ID and cull PI animals
Mix ewe lambs/gimmers w/ main flock 6 weeks before mating
What kind of virus is the Schmallenberg virus?
Orthobunya virus
What fetal abnormalities are seen with Schmallenberg?
Arthrogryposis (curved joints), twisted neck/spine, short lower jaw
How is Schmallenberg transmitted?
Midges
How do you prevent Schmallenberg?
vaccination
decrease vector?
