Veterinary advice: So many ways to bring BVD into your farm that it is frightening
Our client was having serious trouble with his calves following turnout to grass. His calves seemed to go backwards once they hit the grass, with some of them eventually dying.
A lot of advice he received involved mineral deficiency, and copper deficiency in particular.
He tried a number of remedies, including boluses, meal with added copper, and mineral supplementation with extra copper.
He showed me a few of these calves one day, and I was shocked by the state of some of them.
One in particular that I picked out was just a skeleton covered by hide. I recommended putting him down and sending him up to the Regional Veterinary Laboratory for post-mortem.
The following day I had a phone call from the late Eugene Power at the Laboratory.
He had carried out the post-mortem examination, and the result was a classic case of Mucosal Disease/ BVD. He said he could physically scrape copper off the kidneys.
The analysis that came back later showed the copper in the kidneys to be more than 100 times the normal upper level.
The whole herd was blood tested. Six calves and three cows were culled, as animals persistently infected (PI) with BVD.
The next step was a vaccination programme. Every year, this client vaccinated his breeding animals.
With each successive year, you could see the health and thrive of his animals improve. This was about 10 years before the BVD eradication scheme came into play.
You can imagine my shock and horror, when he rang me last year, to inform me that, out of the blue, he had a PI calf.
He was at a loss as to where it had come from. After all the effort we had gone through to eradicate BVD from his herd, I was stunned. He had found no PI in the first two compulsory years of testing.
As we talked, it became apparent he had stopped vaccinating for BVD in the previous year, on economic grounds.
This showed both myself and our client how easy it was to let BVD come back into a herd, when the protection of vaccination lapses.
I have written here in the past about another client who I discovered, during the course of a BVD investigation, had brought two heifers home from the mart unsold.
These returning animals brought BVD back to his farm. One of the recommendations to this client was to vaccinate for BVD. However,l when the investigation was carried out, we were well into the breeding season and, even though he vaccinated without delay, one of his heifers had already picked up BVD from the residual infection on the farm and subsequently gave birth to a PI this year.
I have heard recently of another farmer, going to the knackery with a dead calf.
Upon returning home, he set about tagging some new-born calves, and the entire batch he tagged that day turned up positive for BVD.
In subsequent testing, three weeks later, they all passed the test. Obviously, he had brought the BVD virus back with him from the knackery.
There are so many different ways to bring in this virus to your farm that it is frightening.
If we are to ever completely rid the country of BVD, we must respond to the threat of residual virus in the country which, the academics tell us, can survive in the environment up to five years.
If you have any issues with BVD, or which vaccine to use, give your local vet a call, and discuss it with him or her before you make a decision.
