Jeanne - Simme Valley":1cvzzozo said:
kenny thomas":1cvzzozo said:
Ken can you tell us more about the immunuty. Or start a different topic.
If a cow is negative - she is negative for life. If she gets sick during early stage of pregnancy, she is NOT a PI animal - but, her calf is - if it survives.
Ken - how viable are the calves that survive? Are some just as healthy acting as a non-PI calf? Or are they puny at birth and we manage to keep them alive?
Jeanne, a bit of both. Most times they are smaller, stunted and just have that look to them but I have also heard of successfull show cattle turning up as being PI's. Nowadays I think they have to be tested before going to shows.
Kenny the immunity from natural infection was supposed to be lifelong but now I think they believe not that long however if a heifer group is exposed to a PI well before joining then most will be protected by the time they are bred. The actual disease of BVD is mainly a risk in intensive livestock situations like a feedlot where it lowers the immunity and the likes of pneumonia takes hold. In a breeding herd it is mainly a fertility problem with the biggest crashes being in a naieve herd where you get a lot coming up open and some unproductive calves however after a year or two without any action things will revert to normal as the breeding cows develop their immunity.
Ken