Sheep productivity in an Astrebla grassland of south-west Queensland

A grazing study conducted between 1979 and 1983 assessed the seasonal trends of ewe productivity in Astrebla grassland in southwestern Queensland. This study was designed originally to compare productivity on two pastures with different compositions, however, these differences in pastures composition were not achieved. Large differences in liveweight, wool growth and reproductive performance occurred between years in response to differences in pasture growth resulting from large variation in the seasonal incidence of rainfall. Rainfall effective for plant growth, both forbs and grasses, resulted in a high quality diet which resulted, in turn, in increased sheep productivity. Reproductive performance was particularly sensitive to the quality of the ewes diet around the time of lambing through the effect of diet quality on lamb survival and growth rate. It is suggested that the effect of rainfall on reproductive performance is of greater importance than the yield of forbs present in the pasture