Maintenance of Merino sheep fed varying protein roughages with or without supplements of chopped lucerne hay and wheat.

Abstract

Merino wethers of 30 months of age were hand-fed in pens on low-(chaffed wheaten straw), medium-(84 per cent chaffed wheaten straw; 16 per cent chopped lucerne hay), and high-protein roughage (chopped wheaten hay, or 67.5 per cent chaffed wheaten straw : 32.5 per cent chopped lucerne hay) alone, or supplemented with wheat grain at daily or twice-weekly intervals. The experimental period was 26 weeks and emphasis was placed on the number of survivors, changes in body weight, and mean daily roughage intake. Data were also collected on wool production. No sheep survived on the low-protein roughage (LPR-2.7 per cent crude protein (CP) ). Seven out of 16 sheep in the medium-protein roughage group (MPR-5.2 per cent CP) survived for 26 weeks ; six of these, however, died in the following four weeks. All sheep survived on the two high-protein roughage diets (HPR(1) and HPR(2)-7.6 per cent CP). The wheat supplement increased the number of survivors in the LPR and MPR groups. There was no difference between results from the daily and twice-weekly supplemented groups. Mean daily roughage intake of the unsupplemented sheep increased at each level of protein in the roughage. Mean intake of chaffed wheat straw when fed alone was 220 g per sheep per day. The intake of the same straw when fed with chopped lucerne hay increased by 120 g per sheep per day in the group fed MPR, and by 344 g in the group fed HPR(1). The wheat supplement did not increase intake within any roughage group. Roughage intake was significantly decreased on the HPR(2) diet when a wheat supplement was given. Sheep fed HPR(2) grew more clean wool than sheep in the other unsupplemented groups. Differences between mean clean wool weights of daily and twice-weekly supplemented groups within each roughage group were not significant, but differences between the mean pooled wool weights of each supplemented roughage group were significant.