MINERAL SUPPLEMENTATION AND WOOL PRODUCTION OF YOUNG MERINO SHEEP ON THE SOUTH COAST OF WESTERN-AUSTRALIA

Wool-free liveweight change (LWC), wool growth rate, annual wool produ ction, and wool characteristics of young Merino wethers fed supplement s of lupins with gypsum or a multi-element mineral lick were examined in 12 experiments at 5 farms between 1989 and 1992. The source of shee p varied between experiments; age was 4.5-6.5 months and liveweight 28 -37 kg at the beginning of supplementation. Sheep were fed lupins, lup ins coated with gypsum (15-20 g/kg lupins), or lupins along with acces s to the mineral lick (offered at 140 g/sheep.week). The amount of lup ins offered in all treatments within any experiment was the same. Supp lementary feeding varied between experiments from 150 to 240 days. The sheep grazed annual pastures at stocking rates of 8-16.7/ha. Average lick intake was 12-18 g/sheep.day. During supplementary feeding, there was considerable variation in LWC (-80 to +110 g/day) and clean wool growth rates (3.8-15.1 g/day) within and between experiments, However, there was no significant positive effect of gypsum or mineral lick su pplementation on LWC or clean wool growth rates during or after supple mentary feeding in any experiment. There were positive (P<0.01) relati onships between LWC and clean wool growth rates during supplementation . Also, for some spring-shorn sheep types, staple strength of wool was linearly related (P<0.01) to LWC in the period before the position of break in the wool staple. Annual wool production, average fibre diame ter, and staple strength of midside wool were not significantly increa sed by supplements of gypsum or mineral lick in any experiment.