Animal Production in Australia A COMPARISON OF MAIZE AND MOLASSES SUPPLEMENTS FED TO FRIESIAN YEARLINGS GRAZING AN IRRIGATED GRASS PASTURE IN THE TROPICS

Forty-two Friesian steers, on average eight months old and 128 kg live weight, grazed Setaria anceps cv. Kazungula pastures for nine months at a stocking rate of 12 animals/ha. Pastures were irrigated and fertilized with 730 kg urea, 490 kg superphosphate and 120 kg muriate of potash/ha/annum. Urea was applied in equal monthly applications. Steers were provided with equivalent amounts of dry matter as maize or molasses. Levels of supplementation were 0, 0.5, 1.0 and 1.5 kg/day for maize and 0.6, 1.2 and 1.8 kg/day for molasses. Mono ammonium phosphate (MAP) was added to molasses at 1 % of the supplement. Supplements were group fed to treatment replicates of three animals. Supplementation increased liveweight gains. Over the nine months there was no significant difference in response between the two supplements and the relationship between liveweight gain (Y, kg/day) and the four dry matter levels of supplementation (X, kg/day) was described by the pooled linear regression equation: Y = 0.439 + 0.128 (2 0.021) X; RSD = + 0.063