SUPPLEMENTATION OF YOUNG MERINO SHEEP GRAZING ANNUAL PASTURES WITH LUPIN, BARLEY-GRAIN, OR SILAGE

We examined the effects on liveweight change and wool production of su pplements of lupin, barley grain, or silage given to Merino weaners (a ge 5-7 months; starting weight about 30 kg) grazing dry annual pasture s. In experiment 1, each supplement was offered at 5 rates (g/sheep.da y): lupin, air-dry, 75-450; barley, air-dry, 80-480; silage, fresh, 43 0-2580. Sheep on all treatments gained weight in the first 29 days of supplementary feeding, with no effect of rate of supplementation (lupi n 97 g/day; barley 57 g/day; silage 74 g/day). Those receiving no supp lement also gained weight (40 g/day). Different supplements were not c ompared because the energy levels of lupin and barley were not measure d. Over the next 48 days, liveweight changes increased (P<0.001) linea rly with rate of feeding of lupin (25 +/- 2.1 g/100 g) and barley (12 +/- 0.8 g/100 g). The trend with silage (11 +/- 5.0 g/kg) was not sign ificant. Taken over the 77 days, liveweight changes increased (P<0.01) linearly with rate of feeding for lupin (20 +/- 1.8 g/100 g), barley (8 +/- 1.7 g/100 g), and silage (10 +/- 2 g/kg). There were no signifi cant (P>0.05) differences associated with the rate of supplementation for annual clean fleece weight (lupin 3.43 kg, barley 3.37 kg, silage 3.30 kg) or mean fibre diameter of the 12-month fleece (lupin 22.2 mum , barley 22.6 mum, silage 22.1 mum). In experiment 2, sheep were given no supplement, lupin, barley, or lupin and barley mixtures (metabolis able energy ratio, 1:3, 1:1, 3:1). All supplements increased liveweigh t change (P<0.01) and clean wool growth rates (P<0.05) compared with n o supplement. There was also a trend towards an increase in total wool grown by supplemented sheep (3.81-4.00 nu. 3.73 kg). Liveweight chang e during the first 71 days of feeding increased (P<0.01) as the propor tion of lupin in the supplement increased, with no effects in the fina l 70 days of supplementation. During supplementation, clean wool growt h rate increased (P<0.05) as the proportion of lupin in the mixture in creased, but there was no significant effect on the total amount of wo ol grown over 12 months or on mean fibre diameter. Supplements resulte d in increased (P<0.001) staple strength when compared with controls ( 21-25 v. 14 N/ktex).