Ranchers should screen herds for BVD-PI animals
MONTANA - Montana cattlemen can improve their herd health and biosecurity on their ranch operations by screening their cattle for those who are persistently infected with bovine virus diarrhea and eliminating those animals, according to a Montana veterinarian.
6 March 2007
2 minute read
Bovine virus diarrhea, commonly known as BVD, affects the cattle's immune system and can cause open cows in the fall, late breeding, stillborn or deformed calves or symptoms similar to that of a cold, Dr. Bruce Hoffman, DVM, of Manhattan, Mont., explained during an interactive television seminar conducted last Wednes-day on the Montana Beef Quality Assurance's BVD screening project.
“Seventy to 90 percent of BVD infections go unnoticed,” he said. “Most of those infected look normal - maybe they'll have a little runny nose or a higher incidence of scours.”
There are two types of BVD infections - transient infections, where the calf's immune system fights off the virus after a few days with good management and persistent infections, where the calf's immune system recognizes the virus as part of itself and doesn't fight it leaving the calf infected and spreading the virus to other cattle.
Persistently infected animals are believed to be created during gestation when a cow is infected with the virus between day 40 and day 150 of gestation, Clint Peck, Montana Beef Quality Assurance program director.
“The virus gets in the cow's bloodstream and passes through the placenta to the fetus where it hides in the developing immune system,” he explained. “Then when the calf gets older, the immune system recognizes the virus as part of itself and doesn't fight it.”
Source: The Prairie Star
