A microscopic parasite believed to be responsible for hundreds of California dairy cattle abortions that cost the dairy industry $35 million each year has been identified, isolated in the laboratory and transmitted to cows, report researchers at the UC Davis School of Veterinary Medicine and the California Veterinary Diagnostic Laboratory Systems. Known simply as bovine Neospora, the one-celled protozoal parasite is passed from an infected mother cow to her fetus, causing it to be aborted or to be born infected and, in some cases, partially paralyzed. "Spontaneous abortions are a serious problem for the dairy industry, because cows that abort either do not produce milk or have reduced milk production," said Dr. Patricia A. Conrad, a bovine Neospora researcher and parasitologist in the UC Davis School of Veterinary Medicine. Conrad and colleagues are continuing to investigate where the infection originates and how it is spread, why cows get repeated infections and why the timing of infection during pregnancy is crucial. They also are working to develop tests that identify the presence of the parasite in the blood or tissues of an infected animal.