Bovine Flash Notes - Abortion Flashcards
what causes infectious bovine rhinotracheitis?
bovine herpes virus 1
T/F: clinical signs are seldom seen in dams with abortions due to IBR
TRUE
what does an aborted fetus due to IBR look like?
focal necrotizing lesions of tissue
how is IBR causing abortions prevented?
intranasal MLV for breeding cows (won’t cause abortions), can use IM MLV in feedlot young & open females without risk of causing abortion
what is the presumed cause of abortion due to actinomyces pyogenes?
maternal bacteremia
when does actinomyces pyogenes cause abortion in cattle?
can occur at any stage but most often in late gestation plus or minus a retained placenta
how is actinomyces pyogenes diagnosed as a cause of abortion?
isolate in nearly pure culture from abomasal contents from fetus, rule out other causes
what are the most common lesions seen with an abortion from actinomyces pyogenes?
placentitis & bronchopneumonia
what is the etiology of bovine campylobacteriosis?
campylobacter foetus venerealis - obligate parasite of the bovine genital tract that doesn’t affect other species, gram negative curved or spiral rod that is motile
how is campylobacteriosis transmitted?
coitus
what are the carriers of campylobacteriosis?
subclinical carrier bulls - crypts of the prepuce
when does campylobacteriosis cause abortions?
sporadic abortions at 5-6 months
what is the pathophysiology of campylobacteriosis?
vaginal infection that persists for 2-3 months that will prevent conception or cause early embryonic death with irregular returns to estrus - problem in replacement heifers, less common abortion in cows up to 8 months gestation
what are the big clinical signs associated with bovine campylobacteriosis?
infertility, early embronic death, carrier bulls, causing repeat breeders, & a low % abortion
how is campylobacteriosis prevented?
vaccinate heifers with killed bacterin 1 month before breeding & booster 2 weeks later, vaccinate bulls with 2.5x dose of cows repeatedly to prevent carrier state, revaccinate bulls & cows annually, AI from non-infected bulls or treat semen with streptomycin
T/F: AI exclusively controls disease by prevention
TRUE
how is campylobacteriosis treated?
animals will recover spontaneously within 5 months, so isolate - will resist reinfection after this
how is trichomoniasis diagnosed in cattle?
diamond’s media - culture of preputial smegma from fornix of bulls, cervicovaginal mucus, uterine exudate, placental fluids, or fetal abomasal contents
how are bulls with tritrichomoniasis treated?
imidazole, dimetridazole, or metronidazole
how are cows with tritrichomoniasis treated?
either cull or give them 3 months of sexual rest
how is tritrichomoniasis prevented?
AI reduces but doesn’t eliminate the chance of infection, young bulls in natural breeding helps to reduce incidence
T/F: young bulls are resistant to infection from tritrichomoniasis
TRUE
what are the main clinical signs caused by tritrichomoniasis?
early embryonic death, high non-pregnancy rate, increased calving intervals up to 100 days, & early occasional abortion around 3-4 months
what is the number one mycotic cause of abortions in mares & cows?
aspergillus fumigatus
when do mycotic infections cause abortion?
3rd trimester - often near term
what is a possible sequelae of mycotic abortion?
retained placenta
how is mycotic abortion diagnosed?
last trimester abortion with a retained placenta, leathery placentitis, & culture
is fertility affected by mycotic causes of abortion?
nope
how is mycotic abortion prevented?
reduce exposure to fungus
when does brucellosis cause cattle to abort?
after 5 months gestation
what are some sequelae of brucellosis?
retained placentitis, mastitis, & lameness
how is brucellosis diagnosed as a cause of abortion?
culture of brucella abortus from fetal lung, fetal abomasal contents, placenta, uterine, or mammary secretions, titer of 1:100 for unvaccinated animals & 1:200 for vaccinated animals
how is brucellosis prevented?
b. abortus strain 19 given to calves 4-12 months old to increase resistance to infection with a USDA tattoo in the right ear of vaccinated animals. replacement animals (vaccinated calves or non-pregnant heifers), pregnant/fresh cows kept in brucellosis free areas, & isolating replacement animals for more than 30 days & retesting before adding them to the heard
what screening tests are used for brucellosis in dairy herds?
brucella milk ring test every 3 to 4 months to ID infected dairy herds - if positive, individual blood tested on all with reactors slaughtered
what screening tests are used for brucellosis in non-dairy herds?
market cattle testing - serum is collected from cattle for slughter at market, reactors are traced to herd of origin & all animals tested, & reactors are slaughtered
what classifies a herd as being brucella free?
herds maintained by BRT/MCT & slaughter with 2-3 successive negative tests given at regular intervals
when does foothill abortion cause cattle to abort?
late in gestation - around 6-7 months, or they will have very weak calves
T/F: cows with epizootic abortion don’t show clinical signs
TRUE
what transmits epizootic bovine abortion?
soft ticks
how is foothill abortion diagnosed?
enlarged spleen in the fetus seen postmortem, increase in IgG in fetal blood, but no serologic test because agent is unknown
what drug reduces the rate of abortion due to foothill abortion?
chlortetracycline
how is foothill abortion prevented/controlled?
seldom abort in subsequent pregnancies & no vaccine - so, expose heifers to ticks before breeding & change from spring to fall calving to reduce exposure to ticks only during the last trimester
neosporosis causing abortion in cattle is a major problem in what state?
california
what is the only clinical sign associated with neosporosis in cattle?
sporadic/multiple, or storms of abortions - year round abortions!!!!
