Abstract:
Proc. Aust. Soc. Anim. Prod. (1978) 12: 133 CATTLE PRODUCTION ON SUGAR CANE: THE EFFECTS OF SUPPLEMENTATION WITH RICE POLISHINGS T.R. PRESTON # and R.A. LENG* The rationale for the utilisation of sugar cane in cattle production is that about 10 head of cattle can be grown per hectare over a whole year at approximately 1 kg/d if certain constraints to production can be overcome. On sugar cane plus urea, vitamins'and minerals, growth rates of cattle are increased linearly in response to supplementation with rice polishings. About 100 g gain per day is obtained for each 100 g of supplement. Rice polishings contain approximately 25-30% starch, 11% protein (of high biological value) and 11% lipid. This supplement had no apparent effect on total VFA, VFA proportions, pH or ammonia levels in the rumeni indicating that the effect of rice polishings was not on rumen function. Further, theoretical calculations (Leng and Preston, 1976) indicated that if the glucose entry rates (requirements?) observed in lambs were applicable to cattle (on a metabolic body weight basis) then the cattle would have difficulty in obtaining their glucose requirements from propionate and microbial amino acids. For these reasons, using techniques already described, glucose entry rates have been measured in cattle on sugar cane diets supplemented with varying levels of rice polishings. Measurements were made with [2-Tlglucose. Fresh chopped sugar cane was given ad Zibitwn. There was a linear relationship between the glucose entry rate and the amount of rice polishings given (Figure 1). Glucose entry rates (GER) in Zebu x Friesian bulls (200 kg) given freshly-chopped whole sugar cane supplemented with rice Entry rates were measured X--7 h after feeding. polishinqs. The results suggest that some of the starch in rice polishings is directly available to the animal (i.e. without undergoing fermentation in the rumen), and that low glucose availability may be a major limitation to cattle growth on cane based diets. The 'amount of protein bypassing the rumen is not known. LENG, R.A. and PRESTON, T.R. (1976) Trop. Anim. Prod. - lr 1: #scuella de Medicina Veterinaria y Zootecnia, Universidad de1 Yucatan, Merida, Yucatan, Mexico. * Department of Biochemistry and Nutrition, University of New England, Armidale, N.S.W. 2351. 133. Figure 1.
