BVD testing

[robin walker]

As from December first 2011 it is mandatory in Scotland to have your cattle tested for BVD . I know in England this is not the case as yet . However I think it is advisable where ever you are to have this done as it is going to play an important factor in the selling of your breeding stock .
I should mention unlike TB testing which is paid for by the ministry, BVD testing is entirely at your cost.

[Broomcroft]

That's interesting. We vaccinate for BVD each year when the cattle come in. We do this because our vet said that it is almost true to say that there are two types of cattle herd, those that have BVD and know it, and those that have BVD and don't know it. He remarked that that isn't precise, but isn't far off the mark where we are at least.

It's a very simple task. 2mm in the muscle, quick and easy. We only do breeding stock (from 8 months onwards).

[Jac]

We joined a health scheme last year for BVD, IBR, Leptospirosis and Johne's Disease. The Welsh Assembly Government subsidised us for the BVD and Johne's testing which helped us on our way.

[ann]

I believe I am correct in thinking that once you vaccinate for BVD it becomes difficult to test animals so if this is correct, how will anyone who has vaccinated come on if they wish to sell into Scotland.

[Rob R]

I should mention unlike TB testing which is paid for by the ministry, BVD testing is entirely at your cost.

Although you did get supported testing in phase one of the eradication scheme. As it's quite an eye watering cost for a whole herd, I am surprised there are any that didn't get tested when support was available.

[Jac]

I am surprised there are any that didn't get tested when support was available.


It was very limited support £4 per test per animal but you still had to pay the scheme operator membership fees and vets bills for taking the blood.
There is a link on my website where you can download scheme/disease information and also links to some unfortunate lady that had the misfortune to introduce BVD into her herd of Dexters.
http://www.alvecotedexters.net/sac_health_scheme.htm

[Duncan MacIntyre]

BVD is one of the nastiest most insidious and most economically significant of all cattle diseases in the UK. For many years it was poorly understood, but now that we do know how it works control is comparatively simple and eradication perfectly possible, which is why the Scottish BVD Eradiciation Scheme has begun.

The principles of the scheme are not too complicated, and can be followed voluntarily south of the border as well. In fact they will already be in place in thousands of herds which are health scheme members. Being a member of a scheme gives you and your vet a framework to work to and makes it much more likely that it will go according to plan, and I would recommend all cattle owners to become a member of one. There are various levels of membership in the larger schemes, some of the membership charges are only about £30 per year for the less involved schemes.

Yes you will have to pay for the testing, but more is being done to devise means of controlling the disease with minimum testing - either only testing critical groups, or a percentage of them, and sometimes pooling samples, and only going down to individual tests for groups which test positive. For example if you had 50 breeding females and there was one Persistently Infected carrier amongst them, the bloods could be pooled in 5 groups of 10, only one would indicate need for individual tests, so the PI would be found for the cost of 5 (groups) plus 10 (individual) lab tests.

Persistence of BVD in a herd is largely the result of what is termed a PI, that is persistently infected, animal. These are infected in utero, before birth, and their immune system refuses to recognised the virus as foreign, so no antibodies are produced. They are picked out in the lab because of the lack of antibody, but presence of antigen. The antibodies are the proteins produced by the calf or cow to fight of the infection, whereas the antigen is the protien of the virus itself. Antigen is always present in the blood and tissue of PI's.
When an animal is infected after birth it will produce antibodies. There is a small interval after infection where a post birth infection will result in positive antigen and negative antibody tests, but if there is any doubt about it the tests can be repeated in 3 weeks and the difference will show up.

The key to eradication is the identification and culling of PI's, which for the most part will not be good productive animals anyway, and the protection of the remainder of the herd by biosecurity or vaccination or both. The best plan is both, as perfect biosecurity is very difficult, and perfect vaccination is also tricky.

Movement of cattle into a health scheme herd is perfectly possible if certain criteria are met - either the source herd is of equivalent standing, or if of lower standing then a quarantine period with post quarantine testing is required. Similar quarantine periods can be used to allow for contact at shows etc. Movement generally would not be prevented by vaccination, nor indeed evidence of previous natural infection as long as the quarantine period has been followed.

The biggest threat to BVD free herds is the introduction of active infection, or a PI. A PI of course may still be in utero, so introduction of pregnant females which cannot be shown to have been either vaccinated or previously naturally immune before conception. Both of these things can happen either by deliberatly purchasing an animal, but of course the easiest way is by contact across a fence or by breakins or breakouts.

Remember, the cost of BVD can be huge. More than 10 years ago the cost was quite accurately worked out by SAC as £46,000 in the 10 years following introduction of BVD to a previously free herd of 100 suckler cows. It will be no less today.

The cost of testing, vaccinating, and biosecurity can be fairly accurately estimated before you begin, and will be a small fraction of the above.

Discuss it with your vet, and grasp the nettle.

Duncan