Heterosis and Management Effects in Carcass Characters of Angus, Hereford and Reciprocal Cross Cattle

Abstract

Heterosis for carcass characters was estimated from Angus and Hereford crosses. Two data sets were analyzed. Data set I contained records of 1,095 calves placed on feed immediately after weaning. Data set II was made up of records on 210 calves assigned randomly to either immediate feeding or deferred management (wintering, grazing and then feeding). Cattle with Angus sires or dams produced heavier carcasses with higher dressing percentages, conformation scores, marbling scores and final grades, a larger percentage kidney fat and thicker fat cover but lower estimated cutability than cattle with Hereford sires or dams. Steers dressed higher, producing heavier carcasses with higher conformation scores and larger longissimus muscle areas, whereas heifers were fatter and graded higher. Carcasses from deferred cattle were heavier, with higher marbling scores and grades, less kidney fat, larger longissimus muscle areas and higher estimated cutability than carcasses of cattle fed immediately after weaning. Heterosis was observed for carcass weight, longissimus muscle area and measures of fatness in both data sets.