A Retrospective Study on the Relationships of Calving Practices and Vaccination Status of Reactor Animals to the Cost of Eradicating Brucellosis in 79 Dairy Herds

Abstract

A recently completed retrospective study designed to evaluate the factors responsible for these time differences revealed that among the 79 herds examined, the vaccination status of the reactor animals directly controlled the pace of eradication. In 33 herds rapidly restored to a clean status, all the reactors were vaccinated animals. In 46 herds restored more slowly to a clean status, each invariably contained one or more non-vaccinated reactor animals. The presence of non-vaccinated reactors in a herd slows the pace or eradication by increasing the number of animals that ultimately become infected, particularly under circumstances of dry pen style of calving practice. They also are responsible for prolonging herd quarantine periods.