14 February 1997

BVDcaused by infected semen – VR report

BOVINE viral diarrhoea and mucosal disease can be transmitted by infected semen, and can cause persistent infection in progeny.

According to a report in Veterinary Record, Feb 1, 1997, inseminating seronegative cattle – those which have not been exposed to BVD or mucosal disease, and which have no antibodies for those diseases – with semen from persistently infected bulls causes transient infection in dams, and occasionally, the birth of a persistently infected calf.

The Australian-based authors, led by Peter Kirkland, found that three out of 73 Hereford-Angus crossbred heifers in the trial developed pestivirus – the cause of BVD and mucosal disease.

They warn that infected semen can pose a risk to herds, as two of the heifers carried infected foetuses, which would transmit disease either after birth, premature delivery or abortion.

The authors say that losses can be avoided by screening all bulls and other cattle entering AI stations to ensure they are not persistent carriers of pestivirus. They also recommend quarantining all bulls newly introduced to a centre for up to six weeks before collecting semen to prevent transmission by transiently infected animals.