Abstract

Low pasture quality in summer-autumn and feed deficits during winter are major constraints to achieving consistently high growth rates in beef cattle finishing systems. Two experiments were run to investigate the tactical use of grain supplementation as a tool to overcome performance constraints during these seasons. The first experiment was conducted during January-March (8 weeks) and involved 4 supplementation treatments: 0, 2, 4, and 6 kg grain supplement/hd/d. The second experiment was conducted during July-August (8 weeks) and also involved 4 supplementation treatments: 0, 1, 2, and 4 kg/hd/d. Rising 2 year steers were used in these experiments and pre- and post-grazing herbage masses were similar for all treatments within each experiment. During the summer experiment, steer liveweight gains were 0.05, 0.43, 0.65 and 0.80 kg/hd/d for the 4 supplementation levels respectively. During the winter experiment, average liveweight gains were 0.89, 1.08, 1.30 and 1.35 kg/hd/d. After grain supplementation ceased, liveweight advantages were eroded by compensatory gain occurring in the lower supplementation treatments. The average liveweight response to grain was similar in both experiments (0.18 kg liveweight gain/kg DM supplement), but was highest and most consistent at the 2 kg/hd/d supplementation rate. Acidosis was evident in 1 replicate of the highest supplementation treatment in each experiment. The use of a grain supplement can give reliable weight gain responses and could be valuable as a tactical tool to ensure that time and market bound supply contracts are fulfilled during difficult seasons. The use of this practice in systems that supply to commodity markets is unlikely to be economic.

CJ, Boom, and GW Sheath

Proceedings of the New Zealand Society of Animal Production, Volume 58, , 239-242, 1998