MAPPING PRE-SLAUGHTER TRAITS USING THE CANADIAN BEEF CATTLE REFERENCE HERD

¹ Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B5

² DNA Laboratory, Saskatchewan Research Council, Saskatoon, SK Canada S7N OXO

A reference herd for mapping traits of interest in beef cattle was established at the University of Saskatchewan in 1995 on behalf of the Canadian Cattlemen's Association and the Alberta Cattle Commission with matching federal (NSERC) funding (http://skyway.usask.ca/~schmutz). Three heifers and one bull from each of the five major breeds used in Canada: Angus, Charolais, Hereford, Limousin, and Simmental and one additional breed: Belgian Blue were purchased at weaning. DNA was also collected from their parents. These animals were used to create 17 embryo transfer families, 5 purebred and 12 crossbred. Although all of the parental and offspring generation were slaughtered for meat analysis at about 18-20 months of age, this was not completed until December. The cattle were genotyped for 174 markers at about 20 cM spacing. Coat color was scored on the live animal using Smithe color chips from the American Museum of Natural History and individual photographs were taken to record spotting patterns. Fertility measurements, such as scrotal circumference and testicular weight were also taken. "Temperament" was measured using a motion measurement device at weaning (heritability calculated at .35) and 18 months of age. IBD analysis of sib pairs has revealed QTLs for weaning weight and average daily gain on chromosome 2, 8, and 10 and birth weight on chromosome 3 and 9.