Liveweights and ration digestibilities for steers fed oat or wheat rations at near maintenance level

Abstract

Steers of 252 kg initial mean liveweight were fed 0.44 kg of hay dry matter (DM)/head day-1 plus five rates of whole oats, crushed wheat or whole wheat, with the crushed wheat rations providing 0.7 to 1.3 times the estimated energy for maintenance. All-grain rations at these energy levels had been attempted, but resulted in digestive upset, and were abandoned. The results obtained, listed in the order of the above grains, were : 1 ) grain in ration to maintain liveweight: 1.31, 1.41 and 1.85 kg DMIhead day-1 ; 2) additional grain for each 10 kg improvement in liveweight over I2 weeks: 434,466 and 61 3 g DMIhead day-1 ; 3) mean digestible organic matter content (DOM) of rations, tested at the highest and lowest rates of grain : 69.4, 84.5 and 68.3%. The DOM of the oat rations declined by 8.1 units from the lowest to highest rate of grain. The relative liveweight change on oats could not be explained by the DOMs. Nevertheless, the results suggest, for similar conditions to those applying in our experiment, that: 1) whole oats may be at least as good a feed as crushed wheat, and both will be much better than whole wheat; 2) the feed requirement for maintenance may be about 20% less than standard recommendations; 3) even a little hay in the ration, compared with grain only, may greatly reduce the likelihood of digestive upset