The growth of weaner sheep on clover or grass pastures during summer in Western Victoria

Abstract

Three pasture types were grazed by weaner sheep during two summers in the Western District of Victoria: (1) dried off grass-subterranean clover pasture (DP); (2) dried off pasture with a higher subterranean clover content (SUB); and (3) pasture with a high proportion of green strawberry clover. Additional treatments during the first summer included sheep grazing DP and fed a supplement of subterranean clover hay (80% clover) or grass hay (77% grass). Further information was obtained by feeding both hays to penned sheep. The digestibility of the SUB pasture declined between early and mid-summer, crude protein content remained constant and neutral detergent fibre content increased markedly. During both summers, the average growth rates of sheep grazing strawberry clover, SUB or DP were 106, 12 and -2 g/d, respectively. In the first summer, supplements of clover hay and grass hay significantly increased the growth rates of weaners on DP by 39 and 44 g/d, respectively. Sheep supplemented with clover hay or grass hay during the first summer grew 0.44 and 0.28 kg more wool, respectively, than unsupplemented sheep grazing DP. In the winter and spring following both summers, poorly grown sheep showed compensatory growth sufficient to make up for lack of growth during summer. Conservation of subterranean clover dominant pasture as hay, and feeding it as a supplement in summer, appears a more effective means of improving the growth and wool production of weaner sheep than simply grazing the mature plant in situ. However, there would be a much greater potential for improvement if a legume that remained green throughout the summer could be found to substitute for subterranean clover.