Effect of salt/urea blocks on body weight, body composition and wool production of sheep fed low-protein native grass hay

Abstract

Four groups of 20 two-tooth Merino wethers were group-fed ad lib. on low quality pasture hay (3 · 5% crude protein) for 16 weeks. One group (control) was fed the hay without a supplement. Two other groups were fed salt blocks containing 10% molasses, and 5% pollard with either 35 or 20% urea. The fourth group was fed a block containing 20% urea without molasses or pollard. The control group lost 20% of their initial body-weight over the 16-week feeding period. All three groups with access to urea-containing blocks lost significantly less bodyweight than the control group. Groups fed molasses-pollard blocks with either 35 or 20% urea lost less than 10% of their initial hotly-weight, while the group fed the block without molasses and pollard lost 12 % of the initial body-weight. The voluntary intake of pasture hay and the faecal dry matter output were increased by urea block supplementation. Weight of clean scoured wool was increased, though not significantly, in groups given urea-containing blocks.