Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. 18 USE OF HAY IN GRAIN DIGESTIBILITY TRIALS WITH SHEEP P. HEAZLEWOOD* and T. HAY* Previous attempts at diet for sheep have of this study was determined accurately this institute failed due to a to determine by feeding hay to measure digestibility of grain as a sole The objective high level of inappetence. if the digestibility of grain could be with the grain. Three trials were conducted in an animal house with individually penned 18 month old Merino wethers. The sheep were each offered 500 g/d of whole grain, plus hay ranging from 0 to 200 g/d. There was a 210day introduction period when the daily grain ration was increased from 50 g to 500 g and the hay ration decreased from 500 g to the defined level. The grains fed were barley in experiment 1 and triticale from two sources in experiments 2 and 3, Seven, six, and eight sheep per treatment were used for experiments 1, 2 and 3 respectively. Four sheep in experiment 1 and 2 and eight sheep in experiment 3 were offered 400 g/d of hay in order to determine its digestibility. After the introductory period, the sheep were harnessed for seven days of faecal collection. The faeces from each sheep were dried and bulked daily. The digestibility of the grain in the mixed diets was calculated assuming that there was no interaction between hay and grain, Table 1 Apparent dry matter digestibility (%) of hay and grains (s-d.) fed with hay and proportion of sheep completing trials. The apparent dry matter digestibility of the hay used was calculated to be 60.2 (3-W, 66.1 (1.33) and 64.2 (1.64) respectively in experiemnts 1, 2 and 3. None of the sheep fed on grain alone ate all their ration. Offering 200 g/d of hay enabled the sheep to adapt to a high grain diet. Lower amounts of hay caused inappetence for the grain, leaving too small a number completing the trial. The reason for the large difference in calculated digestibilities of the grain in experiment 2 is unknown. To obtain reliable results in trials intended to estimate the digestibility of grain, sheep cannot be offered less than 200 g of hay with 500 g of grain. * Dept Agriculture and Rural Affairs, Pastoral Research Institute, Hamilton, Vic. 3300. 485