A comparison of the progeny of British Friesian dams and different sire breeds in 16- and 24-month beef production systems 1. Live-weight gain and efficiency of food utilization

Abstract

ABSTRACTThe live-weight gain and efficiency of food utilization of purebred British Friesian steers and of crossbred steers out of British Friesian dams by Aberdeen-Angus, Charolais, Devon, Hereford, Lincoln Red, Simmental, South Devon and Sussex sires were examined in two beef production systems. One system was similar to the commercial 18-month grass/cereal system (16-month system) and the other to a commercial 2-year system (24-month system). The cattle were slaughtered at a standard level of fatness, determined by the use of the Scanogram ultrasonic machine.The trial extended over 3 years and a total of 579 cattle were involved.Data for the two production systems were analysed separately. Adjustment was made to equal age at the beginning of the test and to equal carcass subcutaneous fat concentration.There were important differences between sire breeds in daily live-weight gain (P < 0.05), the order of performance for the different sire breeds being similar in the two systems. Charolais and Simmental crosses grew fastest, followed by South Devon crosses, and then by the purebred British Friesian and the other native breed crosses. Faster growing sire-breed crosses were generally heavier and older at slaughter; they ate more, and there was no obvious relationship between sire-breed means for growth rate and efficiency. The range in efficiency between sire breeds was 27 g and 17 g live-weight gain per kg digestible organic matter intake for the 16- and 24- month systems respectively. In both systems, Hereford crosses ranked highest and the purebred British Friesian among the lowest. Probability levels for sire breed differences were P < 0.1 (16 month) and P < 0.01 (24 month).