Veterinary Biological Products of Viral Origin

Abstract

The responsibility of the Virology Laboratory of Veterinary Services is to evaluate veterinary virus biologics licensed for distribution or presented for licensing.

The first modified live virus infectious bovine rhinotracheitis (IBR) vaccine was licensed in 1958 for use in feedlots. In the rapidly expanding feedlots, IBR infection was a major problem with up to 100% morbidity, and the initial vaccine was readily accepted. These vaccines were of relatively low modification serving to protect calves against infection in feedlots where the disease was endemic. As the use of these vaccines increased and their use outside of feedlots became more prevalent, reports of unwanted abortions were reported. It was recognized that early IBR vaccines 146 did cause abortion in pregnant heifers and was actually used as an abortifacient. A sequel to this problem was a Veterinary Biologics Division label requirement, "Do not vaccinate pregnant cattle," which became mandatory in 1960.