embryonic loss every 4 to 5 years; in these cases, heifers appear to be most vulnerable to Cfv infection as they lack sufficient immunity. Cow- to-cow transmission of Cfv has not been reported. A major risk factor for introduction of Cfv-infection in a breeding herd is the introduction of new animals with unknown Cfv-status, whether these be cows or bulls. Economic losses from Cfv infections can be substantial - such losses include culling non-pregnant cows, culling infected bulls, decreased calves born, decreased weaning weights, and prolonged calving seasons. Campylobacter fetus subspecies fetus Campylobacter fetus subspecies fetus is a commensal organism of the bovine gastrointestinal tract. Campylobacter fetus subspecies fetus is a cause of sporadic abortions in cattle and sheep, but is more of a serious problem in sheep production. Ingestion of fecal-contaminated food or water, rather than venereal transmission as with Cfv, is the route of exposure for cattle. Infection arises from hematogenous spread of the bacteria from the gastrointestinal tract through the uterus to infect the placenta of pregnant cows. Often, this will lead to failure of pregnancy and, more commonly, late-term abortions (i.e., between months 4 to 7 of gestation). Infection of the fetus leads to death, however the fetus is retained for a period of time prior to expulsion. Retention of the deceased fetus causes necrosis of the placenta and placental lesions are not easily distinguished from Brucella abortus, characterized by cotyledon colour change from pink/red to yellow/brown. Other pathologic characteristics of placental necrosis include placental edema and leathery texture. Ovine Campylobacter fetus subspecies fetus Campylobacter fetus subspecies fetus is a normal member of the sheep gastrointestinal microbiome. Transmission occurs through the fecal-oral route or by hematogenous spread from the intestine to the reproductive tract and placenta. Infection from ingestion of Cff-contaminated placenta is also a possible route of infection. Ewes that appear to be particularly sensitive to Cff infection are those with underlying immunosuppression or are naïve to the flock. Campylobacter fetus subspecies fetus localizes in the placenta of the pregnant ewe and may lead to fetal hepatitis. Specifically, in sheep and goats, fetuses aborted due to campylobacteriosis, are often accompanied with an edematous placenta, friable cotyledons and upon necropsy exhibit necrotic foci on their livers. Late-term abortion is the main outcome of a Cff infection. Abortion outbreaks can be seen with Cff in a susceptible ewe herd, where few sporadic abortions are followed by large