One calf that is persistently infected with BVD can severely impact animal health and profitability of a stocker operation. Even with vaccinations, the PI calf, continuously shedding virus, can cause enough exposure to overwhelm immunity in the rest of the herd.

Shaun Sweiger, a consulting veterinarian from Edmond, Okla., works with his stocker clients to test calves for BVD-PI upon arrival. Some, he says, might purchase calves from tested herds that are certified as PI-free, which could eliminate the need to test. But most stockers, he adds, work with put-together groups of higher-risk calves, hoping to “upgrade” their value. Testing is critical in these populations.

If testing identifies a PI-positive animal, Sweiger says the producer needs to remove it and isolate it from the herd. Options for what to do with PI cattle are limited, particularly for lightweight calves too small for a slaughter plant. Sweiger says some stocker clients are isolating and feeding PI calves to add weight before sending them to local lockers for slaughter. Preventing contact with healthy cattle is critical. BVD spreads through physical contact, and he recommends at least an 8- to 10-foot buffer. In many cases, euthanizing the PI calf is the best solution.

Even with testing and removing PI calves upon arrival, Sweiger recommends including a BVD vaccine in the standard vaccination program for stocker cattle. Exposure could have occurred during the marketing process or the animals could be exposed to BVD through fenceline contact with other cattle.