Higher rate of infection
TESTS for BVD, leptospirosis and IBR on herds with unknown status in the Park Vet Group survey show that a large proportion were actually infected.
Of 16 herds not vaccinating for lepto, five were positive and three inconclusive, reveals Peter Orpin. He believes that with known implications for human health, infected herds should be vaccinating. This will also have benefits, such as improved fertility, making it economic.
Negative herds should aim to keep it out. "Avoid buying a lepto positive bull, which could jeopardise the health of the whole herd." It could also enter through contact with urine of infected animals or infected water courses.
Awareness of BVD was high because vets at Mr Orpins practice had made an effort to show producers the benefit of vaccinating or good biosecurity to keep it out. But of 18 herds with unknown status, 13 had suffered recent exposure and were likely to have carrier animals present, said Mr Orpin.
"BVD is now common in the area, but there were a few negative herds." Basic biosecurity would keep it out of free herds. But for infected herds he warned that costs could be high.
For IBR, tests showed that 80% of unknown status herds were infected, he added.