Identification of a Brahman sire whose progeny have high marbling scores and high intramuscular fat content

Abstract

Summary. A Brahman sire (Select Brahman) whose steer progeny had both high marbling scores and high intramuscular fat content has been identified. The effect was independent of dam breed (5 different dam breeds were analysed), was present in both grain-finished and pasture-finished progeny, and was independent of hormone growth promotant treatment. From pasture, over twice as many progeny from the Select sire (62.5%) had high marbling scores as progeny from 10 other Brahman sires (25.9%). The effect was not as marked in grain-finished steers but the Select sire still produced one-third more high marbling progeny (84.6%) than the other sires (63.6%). The Select sire’s progeny were equal to or better than progeny from Tuli sires in producing high marbling scores. The intramuscular fat content (3.5 ± 0.3 g/100 g) of the progeny from the Select sire was greater than double that of progeny from other Brahman sires (1.9 ± 0.2 g/100 g; P<0.0001) and higher than progeny from Tuli sires (2.3 ± 0.1 g/100 g; P<0.0001). The increased marbling and intramuscular fat content were not associated with increased subcutaneous fat deposition, decreased muscle deposition, lower growth rate or smaller mature size since there were no differences in age, hot standard carcass weight, rump fat depth and rib eye muscle area between the Select sire’s progeny and those of other Brahman sires. The identification of a high marbling trait in a Bos indicus sire is of considerable significance to the northern Australian beef industry because it enables markets requiring marbled carcasses to be targeted while maintaining the advantages of tropical adaptation.