Dexter Cattle For Sale Discussion Board

Posted: **Tue Mar 21, 2006 2:38 pm**

Hi I thought I would run this by all you guys to see if anyone can come up with any suggestions.

I have a 8mth old calf which keeps getting the scours,(he was weaned about 6wks ago as I was beginning to think it was his mothers milk which was causing the problem, we have tested for everything exept BVD ( which may have to be the next thing I test for) and everything else has come back clear. He had been wormed and was clear on this count to.

He will pick up for a while and then go back down with the scours, unfortuntely he is a very fuzzy eater and this is also causing problems, as I am trying to keep him on a reasonable amount of roughage, but he will only eat haylage or grass and at the momnet where we are its not possible to turn him out, he has been eatting weaner pellets, but even has off days on these.

I have been involved with cattle all my life but this lad is giving me a headache.

Any suggesttions would be appreciated

Ann

Posted: **Tue Mar 21, 2006 3:55 pm**

Definitely think about blood test for BVD, the normal thing is to test for antibodies and if they are positive then the calf has either had contact with the disease or there may be some maternal anibody present for up to 9 months. If the anibodies for BVD are absent get him checked for antigen -ie the actual virus. If calves are exposed to BVD in utero they may become Persistently Infected, usually referred to as PI's, and are veritable factories for the virus. They should be culled as soon as poss and herd status reviewed.

Posted: **Fri Mar 24, 2006 2:23 pm**

Hi Duncan

can you explain the difference between a carrier and animals which have been exposed and have antibodies.

Do carriers alway infect their calves?

I sold 9 cattle a couple of years ago and they all had antibodies to BVD

Posted: **Fri Mar 24, 2006 4:09 pm**

If cattle are exposed to BVD for the first time, they are infected for a short period and may show varying degrees of illness - often there is nothing much to see. After the initial exposure they form antibodies which remain in the blood for a long time, possibly for life. But the virus is cleared from the body.

If a pregnant cows or heifers are exposed for the first time during roughly 24-100days in calf, some of the calves will be aborted, but some will survive and be born looking reasonably normal but because they were exposed to the virus before their immune system developed their bodies fail to recognise the virus as a foreign thing and they produce no antibodies but remain persistently infected. These calves often do not survive very long but occasionally they do and if they last long enough to produce a calf then their calf will also be persistently infected. However the majority of persistently infected calves die young often after developing a severe form of BVD called mucosal disease. The snag is that whilst they were alive they have constantly produced huge amounts of virus which will infect the rest of the herd.

If infection hits later in pregnancy some calves will be aborted, and some will have congenital abnormalities, and some will be normal.

It is these persistently infected animals which complicate the erradication of BVD so much - unless you root them all out of a herd you have a constant virus factory operating, so if vaccination is not 100% effective, which few vaccines are, the disease can come back. Contact with a neighbouring herd with PIs present is a common reason for recurrence of infection, so unless biosecurity is good erradication should be accompanied with vaccination.

Duncan

Dexter Cattle For Sale Discussion Board

Calf with scour