Infectious causes of bovine abortion during mid- to late-gestation

The accurate and prompt diagnosis of infectious abortions in a herd requires cooperation between the herd veterinarian and a veterinary diagnostic laboratory; working together, with good communication and appropriate sampling and testing, the chances of obtaining an etiologic diagnosis are improved. Abortion diagnosis is a challenge as a cause is usually identified in less than half of submitted fetuses. The majority of diagnosed abortions are attributed to infections by a moderate number of bacterial, viral, fungal and protozoal agents. The pathology and other findings used in the laboratory diagnosis of the major infectious agents causing bovine abortion in mid- to late-gestation will be discussed.