Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/1998
Publication Date: N/A
Interpretive Summary: Breed differences in performance characteristics are an important genetic resource for improving efficiency of beef production. Diverse breeds can be crossed to exploit heterosis, complementarity, and match genetic pot- ential with diverse markets, feed resources and climates. In this report, results are presented for gestation length, calving difficulty, perinatal mortality, calf crop weaned, birth weight, and 200 d weight of progeny by Hereford, Angus, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, Salers, Charolais, Gelbvieh, and Pinzgauer sires with Hereford and Angus dams. Significant differences exist among Hereford, Angus, Shorthorn, Longhorn, Nellore, Piedmontese, Salers, Charolais, Gelbvieh, and Pinzgauer topcross progeny in gestation length, unassisted calvings, birth weight and 200-d wt. For gestation length, birth weight, and 200-d weight, the range for differences between breeds was estimated to be comparable in magnitude to the range for breeding value of individuals within breeds. Breed diff- erences can generally be exploited to optimize performance levels in crosses or in composite populations relatively more quickly than perfor- mance levels in crosses or in composite populations relatively more quickly than performance can be optimized by intrapopulation selection.
Technical Abstract: Gestation length, unassisted calving percentage, perinatal mortality, calf crop weaned (survival from birth to weaning), birth weight, and 200-d wean- ing weight of 2,604 calves born and 2,439 calves weaned are reported for F1 crosses resulting from matings of Angus, Hereford, Charolais, Gelbvieh, Pinzgauer, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, and Salers sires to Angus and Hereford dams (greater than or equal to 3 yr of age) in Cycle IV of the Germplasm Evaluation (GPE) Program at the U.S. Meat Animal Research Center. The Hereford and Angus sires included: 1) Reference sires born from 1963-1971 used in previous cycles of the GPE Program, 2) Sires born from 1982-1985 (80's), and 3) Sires born in 1983-1985 used in natural service clean-up matings. Effects of sire breed of calf were signi- ficant for gestation length, unassisted calving percentage, birth weight and 200-d weaning weight. Gestation length was significantly longer for Nellore than Charolais, Galloway, Longhorn, Piedmontese, and Salers which were in turn longer than Hereford-Angus and Shorthorn. Rankings for birth weight tended to be inversely related to those for calving ease, except for Shorthorn and Salers sires which required low assistance relative to their heavy birth weights. Rankings for 200-d weaning weight among AI sired pro- geny were: Charolais (233.3), Nellore (230.9), Salers (226.6), Shorthorn (225), 80's Hereford-Angus (224.4), Piedmontese (221.8), Galloway (211.2), reference Hereford-Angus (211.1), and Longhorn (200.4), with differences (greater than or equal to 6.6 kg significant.