EFFECTS OF BREED AND SIRE ON CARCASS CHARACTERISTICS AND FATTY-ACID PROFILES OF CROSSBRED WAGYU AND ANGUS STEERS

In a two-year experiment, 54 steers siren by seven Wagyu bulls [Americ an Wagyu Association (AWA) sire numbers 331, 384, 388, 411, 429, 433 a nd 488] and 15 steers sired by two Angus bulls, all out of Angus-Heref ord cows, were used to evaluate the effects of sire and breed on carca ss characteristics and fatty acid composition. Steers were given ad-li bitum access to a high-concentrate diet (15% alfalfa cubes and 85% bar ley supplement) for at least 170 days. Breed and individual sire effec ts were analysed. Wagyu-sired steers had higher marbling, maturity and quality scores, more estimated kidney, pelvic and heart fat, larger l ongissimus dorsi muscle areas, lower fat thicknesses and yield grades than Angus-sired steers (p < 0.05). Steers sired by 388, 411 and 433 h ad lower fat thicknesses than steers sired by Angus, 429 and 488 (p < 0.05). Steers sired by 384 and 388 had higher marbling scores per cm s ubcutaneous fat than steers sired by Angus, 429 and 488, and lower fat thickness per 100 kg of carcass weight than Angus-sired steers (p < 0 .05). For both subcutaneous fat and longissimus dorsi muscle, Wagyu-si red steers had higher (p < 0.05) percentages of 14:0, 14:1, 16:0, 16:1 , and lower percentages of 18:0 than Angus-sired steers. The genetic d ifferences in carcass characteristics among Wagyu sires may enable us to select for improved marbling with less fat in the Wagyu breed. Some statistically significant (p < 0.05) but small differences existed in fatty acid profiles between breeds and among sires. Copyright (C) 199 6 Elsevier Science Ltd