Effects of genotype, sex and stocking rate on postweaning efficiency and value-adding potential at turnoff of weaners grazing improved pasture in the Douglas Daly region of the Northern Territory

Abstract

An experiment was undertaken to establish the effects of genotype, sex and stocking rate on postweaning growth and value-adding potential at turnoff of weaners grazing improved pasture in the Douglas Daly region of the Northern Territory, Australia. The growth of 27 steer and 27 heifer weaners of four genotypes was studied each year for 4 years (i.e. n = 216 animals per year). Animals from each group were run at one of three stocking rates. The cattle were weighed monthly and fat depth was measured ultrasonically at the end of the postweaning year. Genotype had no significant effect on weight gain but one-quarter Charolais × three-quarters Brahman and Droughtmaster animals were significantly (P < 0.0001) leaner than Brahman (purebred and commercial) cattle at the end of the postweaning year. Steers grew more (12%; P < 0.0001) and were leaner (2.6 mm less P8 fat depth; P < 0.0001) than heifers. Animals that grazed at lower stocking rates gained more weight (P < 0.0001) but were not significantly fatter than those at higher stocking rates. The way these factors can be used to produce leaner animals with more value-adding potential for South-East Asian feedlots is discussed.