Impact of Infectious Diseases on Beef Cattle Reproduction

Summary

Bovine pestivirus, or bovine viral diarrhoea virus (BVDV), is an important cause of reproductive failure in cattle but its impact in Australia is unclear. Even less is known about the more recently identified protozoon, Neospora caninum. The aim of this project was to define the impact of these infectious agents on beef production in Australia.
Beef breeding herds representative of the Australian industry were studied. Pestivirus infection was widespread, with active spread in many herds. Herds progress through cycles from high susceptibility, to disease outbreaks after introduction of the virus followed by herd immunity and reduced losses. Without continuous circulation of this virus, the proportion of susceptible animals quickly rises, giving rise to further outbreaks if control measures are not adopted. The impact ranges from the loss of a few calves through to half of the calves born in one year. In contrast, although N. caninum was present, especially in Queensland, its impact appears to be very low.
Recommendations are given to minimise the spread of pestivirus and reduce losses in Australian herds.​​​