Abstract 179

Lindsay,-JA; Mullins,-TJ; Kidd,-JF

Queensland Dep. Primary Industries, Swan's Lagoon, Millaroo, Qld 4807, Australia.

Proceedings-of-the-Australian-Society-of-Animal-Production. 1988, 17, 432; 1 ref.

Digestibility data were obtained from 4 Bos indicus crossbred steers (200 kg liveweight) in a crossover design with 2 treatments and 2 periods. The growth study used 16 Bos indicus crossbred steers (145 kg liveweight) which were fed for 79 days in 4 pens, each of 4 animals. The 2 supplements were: 1 kg/day of whole cottonseed and 0.5 kg/day of cottonseed meal. The steers in the growth study which were fed on cottonseed meal also received urea 65 g/day. A basal diet of low-quality native pasture hay (0.4% N) was given freely. The apparent digestibility of DM and liveweight gain were similar for both diets. However, total DM intake was higher (P <0.05) when whole cottonseed was given compared with cottonseed meal alone. In contrast, when urea was added to cottonseed meal total DM intake was higher (P <0.05) when compared with whole cottonseed in the growth study. This difference is likely to be due to the stimulating effect of urea on roughage intake. Thus, when given at moderate levels whole cottonseed and urea plus cottonseed meal produced comparable liveweight gains with no effect on DM digestibility.