Mandatory bovine viral diarrhoea screening: guidance for vets

PART 9 BVD MYTH BUSTER

1. Got BVD? Don't worry, you can just vaccinate.

FALSE - vaccination does not deal with PI animals. They continue to spread infection potentially creating yet more PIs in spite of herd vaccination.

2. You should keep a PI animal on the farm so that your animals are not naive i.e. the idea of PI parties.

FALSE - PI animals are highly infectious and should be culled as soon as they are identified. They will cause huge problems on your farm. Vaccination is the only effective way of protecting naive animals that may come into contact with BVD.

3. The government is making vaccination compulsory/ the government is banning vaccination.

FALSE - Vaccination will continue to be an important part of controlling BVD for many herds, but it is a decision to be taken between keepers and vets.

4. You can't get rid of BVD, because of transient infection.

FALSE - The evidence is overwhelming that removing the PI animals will stop the disease from circulating. Transiently infected animals are much less infectious than PIs, and only for a short period of time, if they are infectious at all.

5. There's no point in getting rid of BVD, because my herd will be re-infected by sheep/deer.

Sheep can carry BVD and can re-infect your herd, but only if they have been in contact with cattle with BVD in the first place. Removing the source of infection - the PI cattle - will reduce BVD among sheep. Also, transmission from sheep to cattle is very weak, so only a small number will be unlucky enough to get re-infected this way. To be sure though, you should keep breeding cattle away from sheep.

Deer can carry BVD, but we've no evidence to think this is a significant problem, and again, removing PIs will remove a major source of infection for deer.

6. It's impossible to eradicate BVD from my herd - I've been trying for years.

FALSE - The vast majority who have followed a CHeCS scheme have got rid of BVD in under 2 years. If you test to find your PIs, slaughter them, buy in only BVD-free cattle or isolate and test them, test your calves for 2 years, and exercise good biosecurity, you should get rid of a BVD infection in around 2 years. All the studies show that the benefit to your profits will far outweigh the cost of getting rid of BVD.

7. I've got a PI animal, but it looks alright so I don't need to slaughter it, I'll just finish it.

This is a lottery. In some cases a good animal can be finished, but many will die before slaughter age, incurring veterinary costs and spreading virus. While it's on your farm it is a significant disease risk to the rest of your herd. It may well be a hard decision to take, but it's always better to send it for slaughter immediately.