Abstract:
446 Proc. Aust. Soc. Anim. Prod. Vol. 17 CARCASS COMPOSITION OF SHEEP AT A COMMON LIVE WEIGHT AFTER DIFFERENT GROWTH PATHS D. M. MURRAY* AND OLGA SLEZACEK** The empty body composition of sheep fed ad lib. continuously and of others subjected to intermittent weight stasis or weight loss have been compared by Searle and Graham (1975, 1979). They found that, provided deprived animals were allowed to rehabilitate on ad lib. feeding, the empty body composition of continuously fed and deprived animals was similar. The aim of this study was to compare the effects of interrupted growth paths on the dissected carcass composition of sheep. The study was conducted using castrate male progeny of Border LeicesterMerino ewes and Dorset Horn rams. The animals were individually penned and f.ed a pelleted ration of 80 % lucerne chaff and 20% cereal grain. A control (C) group fed ad lib. continuously and three other treatments were studied. All four groups were fed ad lib. from 25 to 40 kg live weight (LW) with the following exceptions:'restricted' (R) group fed to grow from 30 to 35 kg LW at 0.1 kg/day, weight stasis (WS) group fed to maintain LW at 30 kg for 50 days and weight loss (WL) group fed to lose LW from 30 to 25 kg at -0.1 kg/day. Five animals were allocated to each group but only three reached slaughter in the R group due to death of two animals for reasons unknown. Animals in each group were slaughtered, dressed and dissected when they reached a LW of 40 kg. Dissection methods were described by Murray and Slezacek (1976). The dissection results which are shown in Table 1 were analysed for group differences using Duncan's multiple range test. Table 1. Dissected carcass composition of four groups of sheep at a common live weight after different growth paths. The differences between groups in the dissected components were small and not biologically or statistically significant. Thus any compositional changes which may have occurred during the different interrupted growth paths described herein were transient and counter-balanced by appropriate changes in composition during rehabilitation. REFERENCES MURRAY, D. M. and SLEZACEK, OLGA (1976). J. Agric. Sci. Camb. 87: 171. SEARLE, T. W. and GRAHAM, N. McC. (1975). Aust. J. Agric. Res.26: 355. SEARLE, T. W. and GRAHAM, N. McC. (1979). Aust. J. Agric. Res. - 525. 30: *Department of Wool Sciences, University of N.S.W., Sydney, N.S.W. 2033. **Hawkesbury Agricultural College, Richmond, N.S.W. 2753.