Effect of stocking rate, fodder conservation and grazing management on the performance of wether sheep and pastures in south-west Victoria. 2. Seasonal wool growth rate, liveweight and herbage availability

Abstract

The effects of stocking rate, level of fodder conservation and grazing management of Polwarth x Corriedale wethers on the seasonal wool growth rate, liveweight and herbage on offer over a three year period have been examined by pattern analysis. The grazing management systems were continuous, deferred and rotational grazing. The herbage on offer in the autumn and spring of two years, the minimum liveweight in winter for each of three years, and monthly wool growth rates were analysed by regression. The grouping of treatments with similar patterns of seasonal fluctuations indicated some effects due to the treatments and these indications were supported by the regression analysis. Stocking rate was shown to have a major effect on the distribution and amount of feed on offer, especially in the continuous system. Differences between stocking rate in the herbage on offer were reduced by the rotational grazing system, and the deferred system increased the autumn supply of herbage. These general effects were also reflected in the seasonal patterns for wool growth and, to some extent, liveweight. The effect of fodder conservation on herbage availability showed two distinct and opposing responses one during the feeding and the other during the period when hay is conserved. Responses in herbage availability were apparent in late autumn, but by late winter any residual effect on liveweight was small. In the drought conditions of 1967 there was a substantial response in the minimum liveweight in winter to the conservation practice.