Bovine Top Topics - Bovine Abortion Key Agents Flashcards
when does brucellosis cause abortions in cattle?
second half of gestation - around 7 months
what is the difference in vaccines used to prevent brucellosis causing abortions in cattle?
RB51 does not cause antibody production & is used in calves while strain 19 CAUSES antibody production!!!!
T/F: brucellosis is a reportable disease & can cause abortion storms
TRUE
what testing is done to screen for brucellosis in cattle?
screening with brucella ring test or brucellosis card (rose bengal) test
what diseases does brucella cause in humans?
undulent fever
where are the areas where foothill abortion is only seen?
foothill regions of california, oregon, & nevada
when does foothill abortion cause cows to abort?
last trimester abortion storms in heifers or cows new to the area
what transmits foothill abortion?
soft ticks
what does a fetus that has been aborted due to foothill abortion look like?
petechiae & lymphadenopathy
T/F: cows affected by foothill abortion are usually resistant to future abortions
TRUE
when does abortion from leptospirosis occur in cattle?
last trimester
what does a fetus aborted due to leptospirosis look like? what serovar causes an icteric fetus?
usually autolyzed - icterus occurs with serovar pomona
what are the most common serovars of leptospirosis causing abortion in cattle?
hardjo, pomona, grippotyphosa, canicola, & icterohaemorrhagiae
how do you eliminate the renal carrier state of leptospirosis in cattle?
long acting oxytetracycline
T/F: leptospirosis is a zoonotic disease
TRUE
how is leptospirosis causing abortions in cattle prevented?
pentavalent bacterin vaccination every 6 months (usually doesn’t prevent hardjo)
what is the definitive host of neospora caninum? what is another important route of transmission of neosporosis causing abortion in cattle?
dog - vertical transmission is important
when does neosporosis usually cause a cow to abort?
mid to late gestation - usually between 4 & 6 months, endemic or epidemic
T/F: serology from a dam is highly specific for neosporosis as a cause of abortion
TRUE
what is the most common cause of abortion in dairy cattle?
neosporosis
when does listeriosis cause abortions in cattle?
sporadic - usually in last trimester, but can occur at any stage
what do dams with listeriosis causing abortion usually present with clinically?
often ill with fever & metritis but rarely with CNS signs
how do cows get listeriosis causing abortions?
ingestion of poorly preserved silage
what does the aborted fetus due to listeriosis look like?
usually substantial autolysis of fetus & retained placenta
T/F: listeriosis causing abortions in cattle is a zoonotic disease that is reportable in some states
TRUE
when does trueperella pyogenes cause abortions in cattle?
sporadic, may occur at any stage - dam is otherwise healthy
what is the most common bacterial cause of abortion in cattle?
trueperella pyogenes
how is trueperella pyogenes diagnosed as a cause of abortion in cattle?
diagnostic if bacteria is isolated from fetus or fetal membranes
what does an aborted fetus caused by trueperella pyogenes look like?
autolyzed fetus
T/F: mycoplasma can cause sporadic, usually last trimester, abortions in cattle
TRUE
what is the etiology of ureaplasma diversum?
frequently present in vagina & prepuce of cattle
when does ureaplasma diversum cause abortion in cattle?
usually occurs in last trimester
what is seen on the fetus/placenta from a cow affected by ureaplasma diversum?
fetus is not autolyzed - retained placenta & necrotic amnios
what bacterial/protozoal causes are most often associated with abortion in cattle?
brucellosis, epizootic bovine abortion, leptospirosis, listeriosis, neosporosis, trueperlla pyogenes, ureaplasma diversum, & mycoplasma spp.
what are the two main viral causes associated with bovine abortion?
BVDV & IBR (BHV-1)
what signs may a cow have concurrently or up to 4 months prior to abortion with BVD?
upper respiratory signs
when does a cow affected by BVDV have an abortion?
at any stage - may cause abnormalities in fetus or calf
how do you diagnose a cow with BVDV causing an abortion?
PCR or fluorescent antibody
how is BVDV associated abortion prevented?
vaccinate at 6 months of age & annually before breeding
what clinical signs may be seen prior to abortion in a cow with IBR?
abortion storms 100 days after last clinical case of respiratory IBR usually during the second half of pregnancy but any time is possible
when does IBR usually cause a cow to abort?
usually second half of pregnancy, but any time is possible
how are IBR associated abortions prevented?
vaccinate pregnany cows with INTRANASAL MLV only
why not use the IM modified live vaccine for IBR?
IM MLV may cause abortion
between BVD & IBR associated abortions, which is increasing in incidence & which is decreasing?
BVDV is INCREASING & IBR is DECREASING
what venereal diseases are known to cause abortions in cattle?
campylobacteriosis, chlamydiosis, & tritrichomoniasis
what is the pathogenesis of campylobacter causing abortion in cattle?
causes infertility & embryonic death
when does campylobacter cause cattle to abort?
occasional abortion at 4-8 months gestation
how is campylobacter associated abortion diagnosed?
culture (difficult, use clark’s media), vaginal mucus agglutination test
how is campylobacter associated abortion prevented/controlled?
vaccination helps eliminate bacteria (give bulls double dose) & control disease with artificial insemination
when does chlamydiosis cause cattle to abort?
sporadic - usually near the end of the 3rd trimester
T/F: chlamydiosis is a zoonotic disease that causes abortion in cattle
TRUE
what clinical signs are associated with tritrichomoniasis causing abortions?
infertility & pyometra
when does tritrichomoniasis cause a cow to abort?
early abortion - first half of pregnancy & retained placenta
what animal serves as a carrier of tritrichomoniasis?
bulls
how is tritrichomoniasis diagnosed in cattle? how is it treated?
culture of preputial wash or aspirate - treat with imidazoles
T/F: tritrichomoniasis is reportable in some states
TRUE
what are the main mycotic agents known to cause abortion in cattle?
aspergillus spp & mucor spp
when does aspergillosis/mucor spp. cause cattle to abort?
sporadic abortion around 4 months gestation
what is seen grossly that indicates a mycotic cause of abortion?
fungal placentitis & retained placenta
what does an aborted fetus due to a mycotic cause look like?
fetus may be dehydrated & may have grayish/red, elevated skin lesions on head & shoulders
how are mycotic abortions prevented?
avoid feeding moldy silage to pregnant cattle
what are some examples of non-infectious causes of abortion in cattle?
genetic, heat, malnutrition, medications, plants, & toxins
what are some examples of genetic causes of abortion in cattle?
lethal genes & genetic malformations of fetus (fetal monsters) usually aborted in late pregnancy
how does heat cause cattle to abort?
most often due to pyrexia rather than environmental heat causing fetal hypotension, hypoxia, & fetal acidosis
when does heat cause cattle to abort?
usually early term
malnutrition associated with copper deficiency causes what clinical signs in cows that are at risk of aborting?
infertility & abortion - poor growth & loss of hair color
malnutrition associated with vitamin A causes what clinical signs in cows?
abortion, weak calves, & retained placentas
what drugs if inadvertently given can cause abortion in cattle?
dexamethasone, prostaglandins, & xylazine
what is the toxic part of locoweed? why can it cause abortion in cattle?
astragalus or oxytropis - indolizidine alkaloid - causes abortion or birth deformities
what are the side effects seen from a cow that ingests poison hemlock?
abortion & arthrogryposis
desert shrub, if ingested by a pregnany cow, causes what?
abortion & retained placenta
how do ponderosa pine needles cause abortion in cattle?
cows develop a taste preference over normal feed - abortion may occur if pine needles are ingested in the third trimester, abortion may be accompanied by profuse uterine hemorrhage - toxic principles are isocupressic acid & labdane resin
how does sweet clover cause abortion in cattle?
contains dicumarol - dam shows signs of hemorrhage
T/F: a dam with aflatoxicosis will present acutely ill & may abort her fetus
TRUE
T/F: nitrates/nitrite poisoning is a controversial cause of abortion in cattle because there is a lack of proof that it actually causes cows to abort but is thought that it causes abortion when ingested at high levels in late gestation
TRUE
