The Montana BVD-PI Herd Screening Project, a program designed to improve the overall health of the state's cow herd and add value to its calf crop, is currently underway. The focus is to investigate the role of screening cattle herds for animals persistently infected (PI) with the bovine viral diarrhea (BVD) virus, a disease which costs the U.S. cattle industry more than $2B annually.

The first phase of the project concluded with the testing of the ear notches from about 30,000 cattle from 55 Montana ranches, says John Paterson, Montana State University (MSU) Extension beef specialist. Among the PI-positive animals found through the project is what's being dubbed the "PI-Pair" -- a first-calf heifer and her calf.

Bruce Hoffman, DVM, Manhattan, MT, and president of Animal Profiling International (API) says finding both a calf and its mother that are BVD PI-positive is very rare; particularly a pair that looks as healthy as any other cow-calf pair in a cattle herd. API is conducting the tests for the Montana project in its Portland, OR, laboratory.

But unfortunately, Hoffman says, because they are both persistently infected with the BVD virus, they are lethal animals that must be separated from their healthy herd mates.

Montana has taken the lead in this voluntary industry driven approach to animal health management. Paterson expects that up to 15,000 more Montana calves will be screened for PI status as ranchers look to take advantage of market opportunities for "PI-free" calves.

Paterson adds that the overall incidence rate of PIs in Montana appears to be just below the national average which is estimated to be about 1 PI animal for every 1000 calves.

"We're working hard to help ranchers find PI cattle and create more awareness of this disease process," he says. "The PI prevalence rate in Montana is very low -- but we want to help make it even lower."

The Montana BVD-PI Herd Screening Project is a collaborative effort of the MSU Beef Quality Assurance program and the Montana Stockgrowers Association.
-- Clint Peck