A comparison of the reproductive performance of ewes grazing Dwalganup of Bacchus Marsh subterranean clover of a mixture of lucerne and burr medic, before and during mating

Abstract

At Wagga Wagga, New South Wales, three groups, each of 90 Border Leicester x Merino ewes, were grazed for two and a half weeks before joining, and for the six weeks of joining on pastures dominated by Dwalganup subterranean clover (Trifolium subterraneum L.), Bacchus Marsh subterranean clover, and lucerne-medic. Lambing percentages were Dwalganup 74, Bacchus Marsh 30, and lucerne-medic 93. The percentages of non-pregnant ewes were 47, 30, and 33 in the Dwalganup, Bacchus Marsh, and lucerne groups respectively. These results are compared with bio-assay values for the oestrogenic potency of the pastures.