Sheep nutrition: II. Determinations of the amounts of grass consumed by sheep on pasturage of varying quality

Extract

A technique for measuring the appetites of sheep on pasture is described.

Results are given to show that sheep consume a bigger ration, in terms of lb. dry matter, when on pasture than when subsisting out-of-doors on the winter type of diet composed of hay, swedes (or kale) and concentrates. This difference was noted even on grass that had deteriorated in quality, in one case as a result of hot, dry weather in early summer, and in a second case as a consequence of cold, dry weather in spring. With young, leafy pasturage at its best, however, the distinction is most marked.

In the March of 1934, to quote but one example, four pure-bred Suffolk wethers, of live-weight varying from 120 to 181 lb., were shown to consume, on a diet of concentrates (350 g. daily), swedes (ad lib.) and chaffed hay (ad lib.), only 80–88 per cent of the amounts of dry matter predicted on the basis of Wood's feeding standards. During the following May, when grazing leafy pasturage of very good quality (digestion coefficient of organic matter = 81·l per cent), the appetites of the same sheep (range of live-weight now from 137 to 201 lb.) were found to have undergone a striking stimulation, the mean daily consumption of dry matter now being from 104 to 117 per cent of the amounts predicted from the standards. This implied that the sheep were consuming 1·13, 1·37, 1·13 and T53 lb. respectively more dry matter per day than they would have eaten had the diet consisted of hay, concentrates and swedes. The increased appetite is to be attributed to the superior palatability of the young grass.