Characterization of Biological Types of Cattle IX. Postweaning Growth and Puberty of Three-Breed Cross Heifers

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Abstract
Postweaning growth, puberty and pregnancy data were analyzed on 267 heifers produced by breeding yearling heifers of 12 crossbred groups (Hereford-Angus reciprocal crosses plus crosses produced by breeding Jersey, South Devon, Simmental, Limousin and Charolais sires to Hereford and Angus cows) to Hereford, Angus, Brahman, Devon and Holstein bulls. Effects of sire breed of heifer were significant for all growth traits and for age and weight at puberty. Holstein-sired heifers had the highest (P<.05) feedlot average daily gain (ADG). Brahman-sired heifers, due to their large weaning weights, had the lowest (P<.05) feedlot relative growth rate (RGR). Other differences in feedlot ADG and RGR were relatively small. Brahman- and Holstein-sired heifers had higher pasture ADG (P<.05) and were heavier (P<.05) at 400 and 550 days of age than Hereford-Angus or Devon-sired heifers. Brahman-sired heifers were older and heavier (P<.05) at puberty than heifers from any other sire breed. Effects of sire breed of the heifers' dam (breed of maternal grandsire) were significant for weights at 200, 400 and 550 days, puberty age, puberty weight and percentage pregnant. Heifers from Jersey cross cows had lower (P<.05) feedlot ADG and RGR than heifers from any other crossbred cow group. Heifers from Hereford-Angus cross cows had the lowest (P<.05) pasture ADG and heifers from Charolais cross cows had the highest (P<.05). Heifers from Simmental and Charolais cross cows were heavier than heifers from any other crossbred group at 400 and 550 days of age, although all differences were not significant. Heifers from Hereford-Angus, Limousin and Charolais cross cows were older (P<.05) at puberty than heifers from Jersey, South Devon and Simmental cross cows. Charolais crosses had the highest average puberty weight. Jersey crosses had the lowest. Even though 99% of the heifers from Limousin cross cows reached puberty before the end of the breeding season , only 69% were classified as pregnant which was the lowest (P<.05) percentage pregnant among the cross bred cow groups. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.