EVALUATION OF ANGUS, CHAROLAIS AND HEREFORD AS TERMINAL SIRE BREEDS ON HEREFORD AND FIRST-CROSS COWS .2. CARCASS CHARACTERISTICS AND RETAILYIELD OF PROGENY

The characteristics and retail yield of carcases of 482 Angus, Charola is and Hereford sired progeny out of straightbred Hereford (H x H), an d first-cross Brahman x Hereford (B x H), Simmental x Hereford (S x H) and Friesian x Hereford (F x H) darns were evaluated. The cattle had been raised and slaughtered for either the vealer (both sexes), yearli ng domestic (both sexes) or the heavy export steer market. The data we re analysed within market type, and at a constant age at slaughter (28 1, 478 and 829 days for vealer, yearling domestic and heavy export car cases respectively) and also at a constant hot P8 fat depth (4.6, 7.8 and 14.9 mm for the three markets respectively) and constant hot carca se weight (160, 200 and 343 kg for the three markets respectively). At a constant age, carcases of Charolais sired progeny were significantl y (P < 0.05) heavier (8-16%, depending on market type), leaner, had la rger eye muscle area and higher dressing percentage than those of Angu s and Hereford sired progeny. This resulted in 12 to 17% (P < 0.05) mo re kg of boneless saleable meat (retail yield) from carcasses of Charo lais sired progeny. At a constant hot P8 fat depth, the magnitude of t he sire breed differences increased, whereas at a constant hot carcase weight, the differences became non-significant or were reduced in mag nitude. At a constant age, progeny of B x H dams had higher (P < 0.05) dressing percentage than those of the other dam breeds for all market types except the vealer market. Progeny of F x H dams had more (P < 0 .05) channel and kidney fat than those of the other dam breeds, even a t a constant hot P8 fat depth. Retail yield, as a percentage of the bo ned side, was highest for carcases of progeny of B x H dams and lowest for those of progeny of F x H dams (70.2% and 70.3% v. 69.1% and 69.2 %, for vealer and yearling domestic carcases respectively, at a consta nt age). Sire and dam breed effects for the individual primal cuts, as percentages of the boned side, were not significant for most of the p rimal cuts, and where significant, the differences were very small.