Production and carcass traits of high dairy genetic merit Holstein, standard dairy genetic merit Friesian and Charolais × Holstein- Friesian male cattle

The increased proportion of Holstein genetic material in the dairy herd has consequences\nfor beef production in Ireland. A total of 72 spring-born male calves (24 Holsteins (HO), 24 Friesian (FR) and 24 Charolais × Holstein-Friesians (CH)) were reared from calfhood to slaughter. Calves were artificially reared indoors and spent\ntheir first summer at pasture following which they were assigned, on a breed basis, to a factorial combination of two production systems (intensive 19-month bull beef and\nextensive 25-month steer beef) and two slaughter weights (560 and 650 kg). After\nslaughter the pistola hind quarter was separated into fat, bone and muscle.\nLive-weight gain, carcass gain, kill-out proportion, carcass conformation and carcass\nfat scores were 830, 811 and 859 (s.e. 14.9) g/day, 540, 533, 585 (s.e. 7.7) g/day, 526, 538 and 561 (s.e. 3.0) g/kg, 1.51, 2.18 and 2.96 (s.e. 0.085), and 3.40, 4.25 and 4.06 (s.e. 0.104) for HO, FR and CH, respectively. Corresponding values for pistola weight as a proportion of carcass weight, pistola muscle proportion and pistola fat proportion were 458, 459 and 461 (s.e. 2.6) g/kg, 657, 645 and 667 (s.e. 3.7) g/kg, and 132, 161 and 145 (s.e. 4.1) g/kg. Compared with the intensive system, animals on the extensive system had a lower (P < 0.001) daily live-weight gain, kill-out proportion and a lower muscle proportion in the pistola. Increasing slaughter weight increased (P < 0.001) carcass weight and carcass fat score and reduced the proportion of muscle in the pistola.\nAllometric regression coefficients for pistola weight on side weight, and total\nbone, muscle and fat weights on pistola weight were 0.898, 0.755, 0.900 and 1.910\nrespectively. It is concluded that HO grew at least as fast as FR but had a lower killout\nproportion. Carcass conformation and fat scores were greater for FR than for HO\nand muscle proportion in the pistola was lower and total fat proportion was higher.\nCompared with FR, CH had heavier carcasses, a higher kill-out proportion and less fat\nand more muscle in the pistola.