Too Much Challenge, Too Little Immunity
The conversation this morning in the vet clinic kitchen was about pneumonia among weaned calves. Initially the primary focus was on one farm. Yet, as we discussed the nature of the problem and possible solutions similar issues on other farms emerged. These were all farms that raise calves in individual pens until about two months and, after weaning, move them to group pens.
The nearly universal situation of overcrowding in transition heifer pens is the most common source of challenging stresses. Also, at this time heifers are making the transition from individual to group housing. Thus we have immuno-suppressed heifers that are being exposed to a new profile of pathogens as they are mixed with other heifers for the first time in their life.
On this farm calves are vaccinated with an intra-nasal vaccine on day two of life. Then the vaccination protocol calls for an injectable modified-live vaccine around four months of age. But, the spike in heifer pneumonia is happening around two to three weeks after the calves are moved into these pens - well before the scheduled second vaccination.
In the long-term, additional heifer facilities are on the planning board. But, the heifers are getting sick now! In the short-term, we talked over ways to boost immunity among these heifers. As we broke up and went off to get ready for today's farm calls the consensus was that the vaccination protocol needs to be modified to add an intra-nasal vaccination.
The farm vet and owner will meet today to talk over this change. They have to decide which vaccine to use, when and where to vaccinate and who will be responsible for getting the job done.