Abstract:
Proc. Anim. Soc. Anim. Prod. Vol. 19 RELATIVE CHANGES IN THE WEIGHTS OF GUT PARTS OF SHEEP DURING LIVEWEIGHT STASIS AND LIVEWEIGHT LOSS N. N. AZIZ and D. M. MURRAY Dept of Wool and Animal Science, University of New South Wales, Kensington, N.S.W. 2033. Alimentary tract tissue of sheep is sensitive to level of nutrition as shown by Murray and Slezacek (1980) in their study of different rates of positive growth. This experiment aimed to evaluate the effects on the weight of separate gut parts when sheep either maintained liveweight or suffered liveweight loss. The Merino wethers used in each study were less than 12 months old and were given a pelleted ration composed of lucerne chaff (0.80) and wheat grain (0.20). Of the 21 animals in the weight stasis study, groups of 5 were killed after 0, 25 and 50 days and 6 at 75 days, at 30 kg liveweight. In the weight loss study, 5 animals were killed at a liveweight of 33 kg and 5 each after 25,50 and 75 days of subsequent liveweight loss at 133 g/day. Full details of feeding, slaughter and dissection are reported by Aziz (1988). Allometric coefficients relating the separate weight of gut parts to total gut weight (less oesophagus) are presented in Table 1. The coefficients indicate the relative decrease in weight of each part in relation to that of total gut during stasis and loss when total gut decreased at a linear rate of 7 and 10 g/day, respectively (P < 0.001). During weight stasis relative rates were similar for the rumen-reticulum, omasum and large intestine although the former decreased at a slower rate than total gut (coefficient cl). The small intestine showed the fastest decrease in weight of all parts during weight stasis and also exceeded that of total gut (coefficient >l). Table 1. Allometric regression coefficients (+ s.e.) relating the log10 tissue weight of the separate gut parts to loglO total gut tissue weight (less oesophagus) during weight stasis and weight loss During weight loss the coefficients for the rumen-reticulum omasum each other and 1. The small intestine again showed the fastest relative large intestine had a slower relative rate than all parts (P < 0.05) and less sensitivity of the small intestine to both treatments, a conservation of faster rate of rumen-reticulum loss during loss than stasis (P < 0.05). and abomasum were similar to rate (coefficient ~1) while the than 1. The results indicate the abomasum during stasis and a AZIZ, N. N. (1988). Ph.D. Thesis, University of N.S.W. MURRAY, D. M. and SLEZACEK, OLGA (1980). J. Agric. Sci. Cumb. 95: 241-50. 417
