Bovine Top Topics - Abortion Overview Flashcards
what is the classic case presentation of a cow that has an early-term abortion?
cow will return to estrus - delayed estrus following insemination
what is the classic case presentation of a cow that has a late-term abortion?
dystocia, retained placenta, uterine discharge, & fetal remnants in uterus
what are some clues you can use to determine how long a fetus has been dead in utero?
12 hours: cloudy cornea, 24 hours: soft/pulp kidneys, cloudy, flocculent, & mucoid abomasal contents, & 36-96 hours: subcutaneous tissues are gelatinous & blood-tinged, soft/friable liver, & pink/red abomasal contents
what are some clues that indicate a cow has had an abortion?
cow previously diagnosed as pregnant & is no longer pregnant, finding the expelled fetus, vaginal discharge/hanging placenta, & circling vultures
what is the timeline of tritrichomonas foetus causing an abortion in the first half of gestation?
fetus is resorbed & not expelled - cow will return to estrus!!! multiple breedings & delayed estrus cycles, short term vaginal infection with self-cure & immunity in cows, economically significant, & REPORTABLE
what is the timeline of heat causing abortion in cattle?
cows in ambient temperatures greater than 100°F, fever, & fetal resorption - occurs in the early-term/first half of gestation
what is the timeline of neospora caninum causing abortion in cattle?
midterm abortion caused by protozoan parasite, occurs between mostly 4-6 months - transmitted to adult cows through canine fecal contamination of feed - calves can be non-autolyzed & dead, or can be born alive with varying severity of CNS disease
what is the primary source of neospora caninum?
dogs are the primary host
what is the timeline of brucella abortus causing abortion in cattle?
2nd half of gestation around 7 months, considered to be eradicated in the USA - pregnant cows become infected with contact with aborted fluids/tissues from infected cows - titers will rise but some infected heifers may not have a titer until the abortion occurs, may cause an abortion storm, & REPORTABLE
epizootic bovine abortion is also known as what? where is the only place it is known to happen?
foothill aborton - western USA
what is the etiology of epizootic bovine abortion?
pajaroellobacter abortibovis gram negative rod bacteria transmitted by soft ticks
what is the timeline of epizootic bovine abortion?
abortions occur 60-120 days after naïve pregnant heifers are moved into contaminated pastures - aborted fetuses will have lymphadenopathy & petechial hemorrhages
what do aborted fetuses look like if the etiology is epizootic bovine abortion?
lymphadenopathy & petechial hemorrhage
what are the 5 most common serovars of leptospirosis that cause abortion in cattle?
hardjo, grippotyphosa, pomona, canicola, & icterohemorrhagica
how is leptospirosis transmitted?
mostly environmental urine to oral transmission except in hardjo which can be venereally transmitted
what do aborted fetuses look like if the etiology is leptospirosis?
white spots in kidneys & petechiae in scleral membranes
when may nitrate poisoning cause abortion in cattle? what clinical signs may be seen prior to abortion?
may cause abortions at intakes greater than 700 ppm nitrate in feed on a dry matter basis, but abortion may be delayed with respect to nitrate exposure - muscle tremors, weakness, anxiety, brown/cyanotic mucus membranes, dyspnea, & tachypnea
how does ponderosa pine cause abortion in cattle?
cows develop a preference for pine needles over feed - high dietary protein increases their risk of abortion
what clinical signs may a cow that aborted due to anaplasma marginale have?
concomitant anemia & icterus
what drugs are known to cause abortions in cattle?
dexamethasone - used to terminate pregnancy if necessary but high risk for retained placenta, & xylazine
what is the timeline of BVDV causing abortion in cattle?
may abort 3-4 months after infection with abortion occurring at any stage of gestation with the fetuses looking normal to stages of mummification - can be venereally transmitted from persistently infected bull semen
how is campylobacter veneralis transmitted in cattle causing abortions?
venereal transmission from bull or cow to bull - reinfection may occur after several years
how does exogenous prostaglandin cause abortion in cattle?
mistakenly injected - may be used for mismating, administered at 7-9 days post-mating & then re-dosed in 7-9 days (high risk for retained placenta)
what is the timeline of infectious bovine rhinotracheitis causing abortion in cattle?
especially 4 months to term (BHV-1) - may abort weeks to months after last clinical case of respiratory IBR, may see abortion storms, & fetuses will have white abomasal plaques
T/F: making a definitive diagnosis of the cause of an abortion in cattle is very difficult
TRUE
T/F: only 20-30% of abortion causes in cattle are diagnosed
TRUE
why are only 20-30% of abortion causes in cattle diagnosed?
fetal tissues are autolyzed, physical non-infectious causes may self-correct, toxic agents have disappeared by the time abortion occurs, & abortion occurs weeks after the infection
what specimens should be collected when trying to diagnose a cause of abortion in a cow?
abomasal contents, decomposed fetus with brain contents collected aseptically, kidneys, cotyledons, intestines, lungs, serum from peritoneal fluid/fetus, vaginal discharge, & any organs with lesions
what testing is done for abortion caused by BVDV in cows?
PCR or fluorescent antibody
what testing is done for abortion caused by neosporis in cows?
titers on the dam are very high in cases of abortion
what testing is done for abortion caused by tritrichomoniasis in cows?
positive cultures with PCR, non-pathogenic intestinal trichomonads sometomes contains specimens, & tag carrier bulls/report to state vet & neighboring farms
what testing is done for abortion caused by campylobacter in cows?
cervical mucus for antibody/culture & fetal tissues for culture - cows will eliminate campylobacter after several estrous cycles
what testing is done for abortion caused by leptospira in cows?
microscopic agglutination titers - can be confusing if cow has been vaccinated but cattle vaccinated rarely will have titers greater than 1:400, PCR or fluorescent antibody on aborted fetal tissues & placentomes
what testing is done for abortion caused by IBR in cows?
immunofluorescence on fetal cotyledons, fetal abomasum, & fetal lungs
what testing is done for abortion caused by nitrates in cows?
analysis of water & feed (diagnostic at greater than 700 ppm dry matter)
what testing is done for abortion caused by brucellosis in cows?
serology on dam’s blood & culture of fetal abomasal contents
what testing is done for abortion caused by foothill abortion in cows?
PCR on fetal tissues
what testing is done for abortion caused by listeria monocytogenes in cows?
culture placenta & fetal abomasal contents
what is the mainstay of preventing abortion in cattle?
good husbandry should keep the abortion rate under 1%
how is abortion caused by IBR & BVD prevented?
appropriate vaccination at 6 months of age with modified-live vaccines & annual revaccination pre-breeding
how is abortion caused by brucellosis prevented?
vaccination with RB-51 vaccine at 4-6 months of age
how is abortion caused by leptospirosis prevented?
vaccinate pre-breeding & mid-gestation, identify carriers of hardjo, & treat carriers with long-acting oxytetracycline
how is abortion caused by campylobacter prevented?
vaccinate infected & at risk cows
how is abortion caused by neosporosis prevented?
keep dogs & other canines away from pastures
how is abortion caused by tritrichomoniasis prevented?
test bulls prior to introduction to cows & repeat tests 2 or more times
how is abortion caused by nitrate poisoning prevented?
dilute or exclude feeds with toxic concentrations of nitrates
how is abortion caused by foothill abortion prevented?
wait until the third trimester, after 160 days, to introduce pregnant heifers to known foothill agent-infected pastures
what agent causing abortion causes a permanent infection in the sheath of the bull’s penis?
tritrichomoniasis foetus
how is trichomoniasis transmitted?
venereal transmission to & from bulls via infected cows
foothill abortion will not happen to a cow if what occurs?
if pregnant cows are moved to contaminated pastures at greater than 120 days gestation
