Like Gary from Kansas, I too am less than impressed with the tieup to BVD. This was heralded several years ago, after research on ONE herd in Cornwall, which turned out to be riddled with both diseases. Subsequent investigation revealed that it didn't stack up, particularly the assumed effect of reverse benefit. That is if there is no BVD, then somehow the cattle are protected against Tb.
Again, like Gary, we have vaccinated for over 8 years now. Cattle receive an annual booster which protects them and their unborn calf, and all the yearlings get 2 jabs before insemination, thereafter coming into the annual group. Our neighbour also vaccinates. Between us we have lost 160 cattle over 5+ years as reactors to the Tb test. That's not to say they've got Tb, but have had contact with m.bovis.
I think it's pretty much accepted that man gave Tb to the animals, but having allowed it to establish as a maintenance reservoir in badgers, we have a big problem in that they are feeding exposure back up the chain. Cattle are only a sentinel of how much is out there, as we are testing and looking for the exposure. The spill over is occurring into other species including domestic cats and humans.
The NBA have put a good paper together using the PQ's and the website. They favour the back up of the 'smart cycler' machines, post movement tests for breeding cattle who have moved home and wildlife management. It will be launched Jan 12th.
Happy New Year Mary,