The Milk Producer - March 2012 - (Page 34)

RESEARCH By Nicole Yada Breeding for resistance Researchers aim to develop genetic evaluation to resist diseases like mastitis N ew University of Guelph recause of higher physiological desearch shows it may be posmands on cows, such as changes in sible to breed cows to resist their immune system or increased mastitis, as well as other diseases, milk production. while improving fertility and enGenetic correlations between hancing herd health. diseases were mostly positive. Researcher Astrid Koeck is tryCows more resistant to one dising to determine if genetic evaluaease are also more resistant to tion can predict disease resistance in other diseases. This may be due cattle. He is working under the joint to a general immune response. supervision of Dr. Filippo Miglior, Professor Bonnie Mallard, departAgriculture and Agri-Food Canada, ment of pathobiology, found cows the Canadian Dairy Network and with high immune response have University of Guelph researcher decreased disease risks. Flavio Schenkel, department of aniIn the team’s latest study, Koeck mal and poultry science. looked at the relationships beCreating a national genetic evaltween milk yield and the three uation system that would provide most frequent dairy cattle disbreeding values for disease-resiseases—mastitis, cystic ovaries and tant traits is the project’s aim. lameness. They found higher milk “In our studies, we’ve found posiyield is genetically linked with tive associations between health and more health problems. fertility and longevity,” says Koeck. “We need to select for milk “This means selection for disease production and health simultaneresistance would inevitably lead to ously, so we can take advantage of selecting cattle with improved fertilthe genes that improve one trait ity and longer herd life.” without affecting the other,” says Selecting for disease resistance could lead The study also examined health to breeding cattle with improved fertility and Koeck. trait heritability. Researchers dis- longer herd life. covered health traits have a low heritability, with mastitis exhibitresistance. One out of five daughters Nicole Yada is a student writer with the ing only two per cent heritability in had a mastitis case in her first lacta- University of Guelph’s office of research. Professor David Kelton is also involved in Canadian Holsteins. tion for the worst bulls, while only Despite this low heritability, reone out of 14 daughters of the best this research. This project is funded by the DairyGen Council of the Canadian Dairy searchers observed large differences sires was affected by mastitis. between cows, based on the best and Disease incidence tends to increase Network and the Natural Sciences and worst breeding values for mastitis during the first lactation month be- Engineering Research Council of Canada. 34 | March 2012 | MilkPRODUCER

Table of Contents for the Digital Edition of The Milk Producer - March 2012

The Milk Producer - March 2012
Contents
Editor’s Notes
DFO Chair’s Message
Dairy Update
DFC Promotion
Farm Finance
Policy Update
Cover Story
Research
Applied Science
Ruminations
Udder Health
Markets
New'N'Noted
Back Forty

The Milk Producer - March 2012