New test detects genetic immunity status of cattle
Someday soon, you may be able to test your cattle to determine their genetic ability to resist disease.
Researchers with the Ontario Veterinary College at the University of Guelph are working on such a test, and preliminary results show that 15% of Canadian Holsteins tested have high-immune response (HIR). The payoff could be huge, especially if AI bull studs incorporate the tests in their sire selections.
HIR cattle are four times less likely to have mastitis, eight times less likely to have metritis, three times less likely to have ketosis and 2½ times less likely to have a retained placenta.
The research centers on an immune-endocrine micro-array chip that identifies bovine genes associated with high, average and low immune responsiveness and determines the genes that affect disease resistance. Cattle as young as two months can be tested.
Working with the Canadian Bovine Mastitis Research Network, the researchers tested 690 Holsteins in 58 herds for their immune response profile. Approximately 15% of the cows were high responders, 15% were low responders and 70% were average immune responders, with some slight differences between provinces, says Kathleen Thompson-Crispi, a researcher at the University of Guelph.
Preliminary results from another study show that HIR cows have the lowest occurrence of coagulase-negative Staph. mastitis infections. However, when cows were challenged with four different strains of Staph. aureus, the results were not as clear-cut. In fact, how cows responded depended more on the strain of Staph. aureus than on their immune status, so HIR is not a cure-all.
The researchers are continuing to test dairy herds to determine the best way to bring the technology to market. Stay tuned, they say.
- April 2011