Aspects of rate and efficiency of gain in beef cattle and heritability estimates

Nine purebred Hereford bulls which had been tested for rate and efficiency of gain at the University of British Columbia, were bred to 99 heifers, 11 heifers to each bull, obtained from commercial breeders. Bach of the offspring, a total of 84, was weaned at 400 pounds and then placed on an individual feeding test, using the same feeding schedule and the same concentrate ration as that used for the bulls. At 800 pounds, the animals were slaughtered, rail graded and several carcass measurements were collected. Daily rate of gain and feed efficiency were computed over three periods. The following correlations were calculated: birth weight and daily gain during pre-weaning period; birth weight and daily gain during post-weaning period; daily gain during pre-weaning and post-weaning period; daily gain during post-weaning period and percentage lean in ribcut; daily gain during post-weaning period and carcass grade. The "r" value of each of the above calculations was found to be "low". There was a very high correlation between rate and efficiency of gain for each of the three periods: 400 - 800 pounds, r = -0.98 400 - 600 pounds, r = -0.97 600 - 800 pounds, r = -0.98 A simple plan for home testing was outlined. This plan calls for selection on the basis of rate of gain during a test period of approximately 5 months. Animals enter the test period in groups with equal body weight and are full fed.Land and Food Systems, Faculty ofGraduat