Sheep production on annual pasture/stubble versus lucerne

Abstract

This research addressed the impact of lucerne in the traditional grazing system of stubble/annual pastures on animal production. One hundred and eighty Merino ewe weaners were allocated to 2 equal groups on a stratified weight basis. One group of animals was maintained on stubble/annual pastures and supplemented with hay and lupins as required. The second group was grazed rotationally on 4 lucerne paddocks. Food on offer was measured initially to establish stocking rates, which then changed as sheep moved from paddock to paddock. A crossover design was employed to estimate compensatory effects of grazing on lucerne during winter compared with annual pastures. To study wool production, 40 weaners were selected from each group. Dyebanding and mid-side patch clipping were used to measure wool growth and fibre diameter over the trial period. At shearing, fleeces from all sheep were sampled to determine wool quality characteristics. All animals gained weight, however, overall the lucerne sheep experienced greater liveweight gain over the trial period than the stubble/annual pasture sheep. During summer/autumn, the average liveweight gain of the lucerne group was significantly higher (P<0.05) than the group grazing stubbles. In contrast, those animals grazing annual pastures over winter gained weight at a significantly higher rate (P<0.05) than those grazing lucerne. Despite differences in nutritive value, the type of pasture the sheep grazed had no effect (P>0.05) on wool growth or wool characteristics. This may have been due, in part, to either the supplements provided to the sheep grazing stubbles during the summer/autumn period and/or to the relatively low stocking rates used in the trial, which potentially enabled the sheep to be highly selective in their grazing.