It is estimated that over half of Australian beef and dairy farms are actively infected with Pestivirus, with the Meat Livestock Association rating it the second highest cattle disease with regards to economic cost to the industry at $114.4 million annually.
The effects of BVDV will depend on the time of exposure.
Most exposed animals suffer transient immune dysfunction, reducing their ability to fend off other disease.
Adult animals that are not pregnant or under significant stress or disease challenge will often show no sign of the disease.
The most significant effects however are reproductive, and will all depend on when exposure occurs.
Following exposure you can expect embryonic loss early in gestation, whilst late in gestation calves may be malformed with congenital defects or simply born small and weak.
If pregnant cows are exposed mid gestation, a persistently infected (PI) calf will result.
PIs are infected with the virus for life, acting as a great source for continued transmission throughout the herd.
So what’s the issue?
Catastrophes from BVDV are rare, only occurring when naïve animals are by rotten luck exposed at a critical time in reproduction or development.
More commonly, we see low but variable reproductive losses.
Whilst the impact of the PI animals may not be consistently evident, maintaining the virus has been found to limit almost every aspect of production.
The first step to determining the Pestivirus status in your herd is to check for active infections.
This can be done very simply in a dairy herd with a bulk milk sample from your vat.
In beef herds, a set of blood samples should be taken from some of the cows in each of your mobs.
If your herd is established as naïve, vaccination can be considered.
The estimated efficacy of the vaccination is approximately 80 per cent.
There is no ‘one size fits all’ for the management of Pestivirus, and your individual operation needs to be considered when thinking about Pestivirus management options.
If you think Pestivirus may be an issue on your farm, or if you would just like a bit more information, call the Finley Veterinary Clinic on (03) 5890 8444.
18°C