Abstract 632

T K Ma, C X Gu, B C Dai, Hebei Bureau of Animal Husbandry and Aquatic Products,13 Yuhua Mid-Road, Shijiazhuang, Hebei 050011, China and E R Orskov, Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB, UK

Livestock Research for Rural Development 1990 2(3): 49-53.

An experiment was conducted with 16 bulls of the Chinese Yellow Cattle breed. They were 12-18 months of age at the start of the trial and the experiment lasted for 182 days. The experiment was a 2 x 2 factorial trial in which the steers were given either untreated or ammonia treated wheat straw ad libitum, together with a daily allowance of either 0.5 or 1.0 kg/d of a supplement consisting of wheat bran (0.75) and cottonseed meal (0.25). Both the effect of ammonia treatment and level of supplementation were significant. The daily intakes of untreated and treated straw were 5.07 and 5.12 kg and the liveweight gains were 0.18 and 0.57 kg/d respectively. The liveweight gains for the bulls receiving 0.5 and 1.0 kg/d of supplement were 0.30 and 0.45 kg/d respectively. The most economic diet was the ammonia treated straw with 1 kg/d of supplement. At the end of the trial, the cattle on that treatment were sufficiently fat for slaughter.