Screening reveals BVD exposure
BOVINE viral diarrhoea (BVD) is one of the most significant viral diseases of cattle in New Zealand.
It is endemic and considered to be common in beef herds. To get an idea of how common BVD is in our local area, we surveyed the exposure in 65 herds during beef pregnancy scanning this year. This was just over athird of the herds we pregnancyscanned. Of the 65 herds tested, 59% were infected or recently exposed to the BVD virus. This is very similar to a recent North Island survey which found 58% of herds had evidence of recent active infection. Interestingly, 28% of herds surveyed were na¨ıve to the virus. The data indicates that the pattern of infection in the local area is probably very similar to other parts of the country.
Farmers are using this information to put BVD control programmes in place for their farms. Research conducted in New Zealand estimated that infected herds have a 5% reduction in pregnancy rates. So there is an economic benefit to controlling the virus. The economic effects could be greater in the 28% of herds that are na¨ıve if the virus were to infect their cattle.
There are three measures that can make up a BVD control programme:
❑ Management and biosecurity
❑ Testing and culling of stock ❑ Vaccination
In a general farming context, people are much more aware of biosecurity since Mycoplasma
bovis was diagnosed last year. Biosecurity doesn’t just apply to M. bovis and is very important for the control of diseases like BVD. In reality, it is a combination of all three measures that make a farm biosecure against BVD. I would encourage you to assess the biosecurity risks for your farm and manage them. Testing and culling can be used to remove infection from a herd or check animals coming into it. Vaccination is an important tool that can be used to make a herd more biosecure, especially when risk factors can’t be managed with management or testing. Timing of vaccination is critical to its success; there is still time prior to the bulls joining the cows this season to be able to use it.
If you know the BVD status of your farm, use the information to start putting a control plan in place. If you don’t know the BVD status, I would encourage you to find out, and in the meantime work on there being a greater than 50% chance that your herd is infected.