Liveweight gains and carcass traits of high grade Simmental, Hereford, Africander x Hereford and Brahman x Hereford feedlot yearling steers

Abstract

Sixty-three high grade Simmental (S), 40 Hereford (H), 96 Africander x Hereford (AH) and 33 Brahman x Hereford (BH) steers were fed high concentrate feedlot rations from about 8 months of age to slaughter at about 12 months to compare their suitability for producing feedlot beef. Selection for slaughter was made when estimated fat cover and liveweight were closest to market requirements (6-10 mm rib fat and 320-360 kg, respectively). The steers were slaughtered in 3 groups and their carcasses electrically stimulated. Mean slaughter liveweights and carcass weights were 398 and 212, 350 and 182, 349 and 189, 335 and 181 kg for S, H, AH and BH, respectively. Daily liveweight gains during the 4 months on feedlot rations were 1.53, 1.37, 1.24 and 1.25 kg/steer, respectively. Fat depths at rib 12-1 3 and sacral crest sites for S, H, AH and BH were 6.2 and 8.1, 7.3 and 10.3, 8.0 and 10.4,7.3 and 10.0 mm, respectively. In the same order, yield of saleable meat was 77.4, 75.7, 76.3 and 77.2%, and the S and BH had less fat trim than H and AH. Warner-Bratzler peak force shear values (kg) and cooking loss (%) were 3.4 and 33, 3.6 and 34, 3.9 and 34, 5.0 and 35 for S, H, AH and BH, respectively. There were no commercially important differences between H, AH and BH in terms of fat cover at preferred carcass weights and tenderness. However, feedlot liveweight gain favoured the H. Although S steers had highest liveweight gains, many steers did not have sufficient fat cover until liveweights were above the preferred range.