Genetic parameter estimates of postweaning growth performance and carcass traits of embryo transfer families

Abstract

Through the advantages related to environmental adaptability and heterosis, Bos indicus type cattle have increased in numbers throughout the southern U.S. By systematically breeding Bos indicus with Bos taunts type cattle, beef cattle production is enhanced, however, it is not without cost as characteristics associated with carcass components are often adversely affected through the infusion of Bos indicits genetics. In order to quantify the magnitude of these effects, the growth performance and carcass attributes of 3/4Angus 1/4Brahman, 1/4Brahman 1/4Angus and 1/2Angus1/2Brahman embryo transfer family progeny (n = 268) were analyzed. The effects of mating type and families within mating type served as the primary genetic components for analytical purposes and allowed for specific comparisons using contrasts. The results demonstrated the effects of breed type for pasture gain, ribeye area, marbling, quality grade and yield grade. Specifically, cattle with 25% Bos indicits inheritance possessed superior marbling and quality grade values approximately one full score over cattle with > 50% Bos indiclis genetics. However, certain families within the -1/4Brahman 1/4Angus mating types produced carcasses with a large percentage of USDA Choice grades. Family within mating type variation was also observed for other traits, demonstrating that genetics within the current population exist that are capable of producing both acceptable and unacceptable consumer related characteristics. Unusually high heritability estimates were obtained which were subsequently attributed to the design and nature of the experiment. Genetic and phenotypic correlations revealed strong associations for growth characters and several carcass quality attributes.