Characterization of Biological Types of Cattle-Cycle II: I. Birth and Weaning Traits5

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Abstract
Gestation length, calving difficulty, perinatal mortality, calf crop weaned, birth weight, preweaning average daily gain (ADG), relative growth rate (RGR) and 200-day weight were studied on 1,591 calves born and 1,494 calves weaned in 1973 and 1974 from 4- to 9-year-old Hereford and Angus dams and by Hereford, Angus, Red Poll, Brown Swiss (domestic and European), Gelbvieh, Maine-Anjou and Chianina sires. Hereford and Angus dams differed (P<.01) for most traits; the Angus dams reflected a generally higher level of maternal performance. Breed of sire effects were important (P<.01) for all traits; the Hereford-Angus, Red Poll and Brown Swiss crosses were superior in perinatal mortality and calf crop weaned whereas the Gelbvieh, Maine-Anjou, Chianina and Brown Swiss crosses were superior in ADG and in 200-day weight. Thus, average weight weaned per cow calving was highest for the Brown Swiss crosses. Level of calving difficulty was greatest (P<.01) in the Maine-Anjou crosses. The Hereford-Angus reciprocal crosses had the lowest level of calving difficulty, but the value was not significantly less than the value for the Red Poll and Gelbvieh crosses. The Brown Swiss, Maine-Anjou and Chianina crosses had a significantly higher level of calving difficulty than that of the Hereford-Angus reciprocal crosses. Age of dam (4-year-olds vs 5-year-olds and older) was important (P<.01) for birth weight, ADG, RGR and 200-day weight. The effects of sex of calf were important (P<.01) on all traits studied except perinatal mortality and calf crop weaned. When the data wereanalyzed with birth weight as a covariate on calving difficulty (with abnormal presentations included as difficult births), perinatal mortality and calf crop weaned; breed of sire, breed of dam and sex of calf effects were still significant for these traits. This result reflects the importance of factors, associated with breed of sire, breed of dam and sex of calf, other than birth weight on these traits. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.