Non-carcass parts and carcass composition of high dairy genetic merit Holstein, standard dairy genetic merit Friesian and Charolais X Holstein-Friesian steers

摘要

The increased use of Holstein genetic material in the dairy herd has consequences for beef production. A total of 24 spring-born calves comprising 8 Holsteins (110), 8 Friesians (FR) and 8 Charolais x Holstein-Friesians (CH) were reared from calfhood to slaughter. At the end of the second grazing season they were assigned to a 3 (breeds; HO, FR and CH) x 2 (slaughter weights; 620 and 730 kg) factorial experiment and finished indoors. After slaughter carcasses were classified for conformation and fatness, all organs and non-carcass parts were weighed, and the right side of each carcass was dissected into fat, bone and muscle. Non-carcass parts, carcass weight, kill-out proportion, carcass conformation score and m. longissimu area were 405, 398 and 368 (s.e. 8.31) g/kg empty body weight, 355, 344 and 383 (s.e. 9.4) kg, 509, 520 and 545 (s.e. 8.99) g/kg, 1.0, 2.0 and 3.1 (s.e. 0.1.6), 7616, 7096 and 9286 (s.e. 223.4) mm(2) for HO, FR and CH, respectively. Corresponding proportions of carcass muscle and fat were 631, 614 and 656 (s.e. 8.4), and 165, 200 and 1.65 (s.e. 1.0.5) g/kg. Increasing slaughter weight increased the proportion of total non-carcass parts, carcass weight, carcass fat score and fat proportion, and reduced carcass muscle and bone proportions. It is concluded that differences in kill-out proportion between the two dairy breeds was primarily due to the lower proportion of gastrointestinal tract (GIT) in FR, and the higher kill-out proportion of CH was mainly due to lower proportions of GIT, internal organs and internal fat. In terms of beef production, HO and FR were broadly comparable for most traits except carcass conformation score and carcass fat proportion, which were lower for HO. CH was superior to the dairy breeds in all important production traits.