Bovine Abortion

The Case-Control Study as a Different Approach to Diagnosis

Abstract

A farm in the Midwest is experiencing problems with abortion. This farm is milking around 80 cows, raises its own heifers at another place, and has a rolling herd average of 16,000 pounds. Heifers are bred with a bull at the other farm and brought to the milking farm 4 - 5 weeks before freshening. These springers are housed in the same area as the dry cows until approximately one week before freshening. All cows are vaccinated with a multivalent vaccine for Leptospirosis, Infectious Bovine Rhinotracheitis, and P13 at the time of dry off. Milking cows are fed a total mixed ration of corn silage, haylage, and high moisture corn. Dry cows and springers are fed corn silage with hay or green chop, depending on the time of year.

On May 1 an aborted calf approximately 120 days gestational age was found in the freestall area. On June 1, one heifer aborted 2 weeks before her calving date. On June 10 another heifer aborted. The veterinarian was called out and he submitted serum samples from both heifers to the diagnostic lab, results were negative. A dry cow aborted on June 15. The fresh fetus and placenta were carried, by the producer, to the diagnostic lab. It will be 2 weeks before results are available. Another heifer and a cow had late term abortions on June 17 and 18. Another cow in the low group aborted twins on June 21. Immediate action is called for but no diagnosis can be made from the laboratory findings.