Lower DD prevalence in high immunity cows

By Steve Mason on

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.

Prevalence of digital dermatitis among groups of cows classified as high, average or low antibody-mediated immune responders. * indicates statistically significant differences in DD prevalence between groups.

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.

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