Management of finishing pastures to maximise carcass gain

Abstract

Special-purpose finishing areas must achieve the maximum output of carcass gain to ensure their cost effectiveness. Liveweight and carcass weight gain were measured from lambs finished on Puna chicory (Cichorium inrybus)/Hakari upland brome (Bromus sitchensis)lPawera red (Trifolium prutense) and Huia white clover (Trifolium repens) pasture for periods of 3 to 18 weeks after grazing medium or low quality pastures over two summers at the Gore Research Station. The relationship between growth of lambs and time on finishing pasture was quadratic in year 1 when chicory comprised 37% of the pasture on offer. Highest live and carcass weight gains were achieved by finishing for between 9 and 18 weeks. In year 2 with a chicory content of 7% all finishing periods produced similar live weight and carcass weight gains. Carcass gain on low quality pasture (year 2) averaged only 3.5 g/100 g liveweight gain compared with of 42 g/l00 g liveweight gain and 47 g/100 g liveweight gain for medium quality and finishing pastures, respectively, averaged over two years. A finishing period of 9 weeks is recommended when chicory levels are high. Increased lamb performance was still evident when chicory content d65lined. No detrimental fat deu. osition was found in faster growing lambs. Skin and wool weights were significantly (P ~0.05) improved through high quality diets. Keywords: carcass weight gains, Cichorium intybus, fat deposition, finishing time, liveweight gain