Several years ago. a group of researchers at the University of Guelph, led by Dr. Bonnie Mallard, developed a method to classify dairy cattle according to their ability to mount an immune response. This method has been applied to identify ‘Immune Plus®’ dairy sires whose semen is now available through Semex® and its worldwide partners.
More recently, Dr. Mallard’s group has reported the results of a study designed to evaluate whether the ability of dairy cows to mount an immune response might be related to their resistance to digital dermatitis (DD). 329 cows in 5 Ontario dairy herds were tested for both antibody-mediated (AMIR) and cell-mediated immune response (CMIR) to antigens administered intramuscularly. Cows were classified as high-, average- or low- AMIR or CMIR responders. Hoof health data were recorded by each herd’s hoof trimmer using Hoof Supervisor® software.
As illustrated in the graph on the right, the prevalence of DD among cows that were classified as high AMIR responders was significantly lower (20%) than that of cows classifed as low AMIR responders (40%); the DD prevalence among average AMIR responders was 35%. There were no significant differences in DD prevalence among the CMIR groups – all were between 32 and 38%.
The authors of the study suggest that breeding for high immune response (presumably by using Immune Plus® sires) may contribute to a reduction in DD prevalence in a dairy herd.
The article, to be published in the Journal of Dairy Science, is available here.