THE incidence of disease in dairy cattle is increasing, and the only way to tackle it has been through management practices and veterinary inputs. That, though, is until now: new genetic technology will help reduce disease levels because sires can now be tested for their immune response, with the best ones chosen in order to pass their genes on to their daughters.
Speaking at this year’s Semex conference, the scientist behind the technology, Professor Bonnie Mallard from the Department of Pathobiology at the University of Guelph, Ontario, Canada, said the new High Immunity Response technology could result in a reduction in disease of between 4 and 8%, and bring financial benefits of £50 per cow per generation – equivalent to the amount gained from production related genetic improvement. The heritability of immune genetics at 25% is similar to that for milk production traits, and far higher than those for longevity (8-10%), calving ease (6-7%), daughter fertility (4-7%) and mastitis (10%).
Disease breakdowns occur when an animal’s immune system does not make an adequate response to a pathogen challenge, either through the first defence mechanism, which is within the cell, or through the second mechanism, which is outside of it, she explained. The HIR technology provides a genetic boost to both of those immune mechanisms. An animal’s immune response can be measured through two relatively simple tests involving three farm visits.