Evaluation of estimated genetic merit for carcass weight in beef cattle: Live weights, feed intake, body measurements, skeletal and muscular scores, and carcass characteristics

摘要: Abstract Genetic merit for growth rate, expressed as expected progeny difference carcass weight (EPD CWT ), is available dairy and beef sires used in Ireland. The once predominantly Friesian (FR) herd has experienced significant introgression of Holstein (HO) genes over the past two decades, cross-breeding cows, not required to produce replacements, with bulls common. objective this study was compare feed intake, live animal measurements slaughter traits Holstein–Friesian cows contrasting maturity breeds namely Aberdeen Angus (AA) Belgian Blue (BB), each selected either high (H) or low (L) estimated genetic weight. Two strains (FR HO) were also included giving six groups total. A total 170 male from spring-calving artificially reared indoors subsequently managed together at pasture until end their second grazing season when they assigned one mean weights (i) 560 kg (Light) (ii) 620 kg (Heavy). Daily intake recorded during first winter finishing. Body four times animals' life, linear scoring carried out 9 months age again slaughter. Carcasses graded conformation fatness (15 point scale). Slaughter per day AAH, AAL, BBH, BBL, FR HO 782, 719, 795, 793, 804 783 (SE 12.9) g, 415, 372, 438, 436, 413 401 5.8) respectively. Corresponding values weight, kill-out proportion, class scale) fat 314, 283, 334, 333, 317 305 4.7) kg, 526, 518, 553, 550, 519 511 2.9) g/kg, 6.2, 5.4, 8.0, 7.9, 5.3 3.7 0.26), 9.8, 9.3, 7.4, 7.2, 9.3 8.2 0.26). There interactions between breed differences H L mainly AA only. Feed animals negligible largely attributable Following scaling had lower skeletal measurements, indicating greater compactness, effect more pronounced AA. It concluded that using on increases rate but may be similar all breeds.