Genetic effects for reproductive traits in beef cattle and predicted performance

• Published in: Journal of animal science Vol. 69; no. 2; p. 531
• Main Authors: Williams, A.R. (Louisiana Tech. Univ., Ruston), Franke, D.E, Saxton, A.M
• Format: Journal Article
• Language: English
• Published: United States 01.02.1991
• Subjects: Animal Husbandry; Animals; BOVIN DE BOUCHERIE; Breeding; Cattle - genetics; Cattle - physiology; CROISEMENT; Crosses, Genetic; CRUZAMIENTO; Female; GANADO DE CARNE; GENETICA; GENETIQUE; Least-Squares Analysis; Male; PARTO; PARTURITION; PERFORMANCE DE REPRODUCTION; RACE; Random Allocation; RAZAS; Reproduction - genetics; REPRODUCTIVIDAD; TECHNIQUE DE PREVISION; TECNICAS DE PREDICCION; VACA; VACHE; VIGOR HIBRIDO; VIGUEUR HYBRIDE; Weaning
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/1991.692531x

Reproductive data were collected on 4,595 cow exposures and subsequent calvings over four generations in a rotational crossbreeding study involving Angus, Brahman, Charolais and Hereford breeds. Direct and maternal additive (Ig and Mg) and nonadditive (Ih and Mh) genetic effects were estimated for calving rate, calf survival, weaning rate, calving assistance and calf birth date. Genetic effects were estimated by regressing individual animal response on the proportion of genes from breed of origin and gene combinations expected for the four breeds in offspring and in dams. Breed direct and maternal additive and nonadditive genetic effects were expressed as a deviation from the least squares mean. Brahman Ig effects decreased calving and weaning rate (-9.5 +/- 4.0 and -11.8 +/- 4.4%) but Mh effects for weaning rate that included Brahman were positive, ranging from 16.5 +/-6.7% for Angus-brahman to 27.8 +/- 6.9% for Brahman-Hereford. The Brahman Ig effect delayed calf birth date (9.8 +/- 2.1 d; P .01), whereas Angus and Hereford Ig effects influenced earlier calf birth dates (-4.3 +/- 1.9 and -4.1 +/- 1.9 d; P .05). Brahman combination Mh effects also influenced earlier calf birth dates (P .01). The Charolais Ig effect for calving assistance was positive (4.3 +/- 1.9%; P .05), whereas Angus-brahman and Brahman-Charolais Mh effects for calving assistance were negative (-6.5 +/- 3.2 and -7.0 +/- 3.2%; P .05) and more desirable. Predicted reproductive traits for rotational mating systems were intermediate between predicted reproductive traits for two- and three-breed terminal crosses. Predicted calving and weaning rates were maximized when Brahman first-cross and Charolais-Hereford cows were used in three-breed cross mating systems