New research from the RVC has found that antibodies against Johne's disease can be detected in the blood of newborn calves after they have received colostrum from their mothers.

Seeking to better understand early life exposure, researchers from the RVC analysed blood samples from 38 newborn dairy calves and their dams on a commercial dairy farm in south-west England. These had originally been collected as part of routine monitoring of whether calves had successfully absorbed antibodies from colostrum.

The team then measured MAP-specific antibodies in the remaining (residual) serum samples and used statistical modelling to examine how these antibody levels related to the mother's Johne's disease status and the efficiency of antibody transfer from colostrum.

The study found that calves born to cows with MAP antibodies had higher levels of MAP-specific antibodies than calves born to cows without detectable antibodies. The relationship between antibody levels and the amount of antibody absorbed from colostrum also differed depending on whether the mother was MAP-seropositive or MAP-seronegative.

Jonathan Hedgecock, RVC veterinary student graduate and lead author of the study, said: “Continued research into new testing strategies for Johne’s disease is important with more work still needed. Many calves are already blood sampled for serum total protein at a young age, so being able to test calves at this age would be straightforward as we wouldn’t need to take additional blood samples nor would we have to wait until they develop disease as adults.”

https://www.mdpi.com/2076-2615/16/13/1963