SUPPLEMENTARY FEEDING PATTERN AND RATE OF LIVEWEIGHT GAIN IN WINTER-SPRING AFFECT WOOL PRODUCTION OF YOUNG MERINO SHEEP ON THE SOUTH COAST OF WESTERN-AUSTRALIA

The effects of different supplementary feeding practices in summer-aut umn and management strategies on green pasture on liveweight change, w ool growth rate, annual wool production and wool characteristics of yo ung Merino wethers were examined at 2 farms. The grain feeding treatme nts were lupins (L) or lupins and oats (LO) fed in amounts that were a djusted to try and maintain liveweight, or lupins and oats (LOG) fed a t a higher rate. The objectives of liveweight maintenance or gain were not always achieved, but liveweight patterns differed between LOG com pared with L or LO during summer-autumn. The sheep used at farm 1 were aged 4.5 months and liveweight 32 kg at the start of the experiment, while those at farm 2 were 6.5 months and liveweight 39 kg. The stocki ng rate in summer-autumn was 8 wethers/ha at both farms. During supple mentation, sheep on LOG had a higher (P<0.05) liveweight change compar ed with those on L or LO (farm 1, 15 v. -8 g/sheep.day; farm 2, -35 v. -51 g/sheep.day) and clean wool growth rates (farm 1, 7.1 v. 6.4 g/sh eep.day; farm 2, 5.1 v. 4.8 g/sheep.day). The sheep on LOG grew broade r (P<0.05) wool than those on L or LO (farm 1, 19.0 v. 18.5 mu m; farm 2, 21.7 v. 20.8 mu m), and at farm 1 length was also greater (P<0.05) (114 v. 111 mm), while at farm 2 staple strength was greater (P<0.01) (22.9 v. 16.4 N/ktex). There were no significant differences in annua l clean wool production. There were positive (P<0.01) relationships be tween staple strength and liveweight change to the time of minimum liv eweight in summer-autumn. After green pasture on offer reached 500 kg DM/ha in autumn, different liveweight change patterns were achieved in 2 groups (LSI lower stocking rates; HS, higher stocking rates) of she ep at each farm by adjusting stocking rates. Within a farm, the LS and I-IS groups were comprised of equal numbers of sheep from each replic ate of the supplementary feeding treatments. There were differences (P <0.05 to 0.01) in liveweight change between LS and I-IS (farm 1, 93 v. 72 g/day; farm 2, 127 v. 60 g/day), the differences being more pronou nced at farm 2. The differential stocking rates at farm 2 resulted in differences in clean wool growth rates (P<0.01), in clean wool product ion (4.22 v. 4.53 kg, P<0.05), and fibre diameter (20.8 v. 21.4 mu m, P<0.01), but there were no significant effects on staple length or str ength. There were no significant effects of the supplementary feeding treatments imposed in summer-autumn on the responses to the stocking r ate treatments on green pasture.