Puberty in Crossbred and Straightbred Beef Heifers on two Levels of Feed

Abstract

Age and weight at puberty in heifers were determined for Hereford, Angus and the crosses between the two breeds. The heifers were allotted to two nutritional levels from weaning to puberty. The average daily gain from 6 to 12 months of age was 0.82 kg. and 0.73 kg. for crossbred and straightbred heifers on the high level of feed and 0.30 kg. and 0.36 kg. for crossbred and straightbred heifers on the low level of feed. The average age at puberty was 381 days for both crossbred and straightbred heifers on the high level of feed, while on the low level of feed the average age at puberty was 424 days for the crossbred heifers and 572 days for the straightbred heifers. The average weight at puberty was 330 kg. for crossbred heifers and 299 kg. for straightbred heifers on the high level of feed and 254 kg. and 268 kg. for crossbred and straightbred heifers on the low level of feed. Thus, an interaction for age and weight at puberty was found between level of nutrition and breed of the heifer.