Five-year old diversified pasture supports greater lamb liveweight gain than a standard perennial ryegrass-white clover pasture

Abstract

This study investigated liveweight gain of lambs grazing five-year-old pasture of either Italian ryegrass, red clover and plantain (Diversified) or perennial ryegrass and white clover (Standard). Coopworth lambs were born to either diversified or standard pasture and reared there until weaning in December (early summer). Liveweight gain (LWG) from tailing to weaning was 23% higher in lambs on diversified pasture (0.335 kg LWG/lamb/day) compared to those on standard pasture (0.272 kg LWG/lamb/day). From summer to autumn (December to May), liveweight, pasture mass, botanical composition and nutritive quality was measured as weaned lambs progressed through rotationally grazed paddocks of either diversified or standard pasture. Similar lamb liveweight gain between pasture types was observed over summer and autumn, with both groups averaging 0.187 kg LWG/lamb/day. From December to May, dry matter intakes (DMI) and feed conversion efficiencies (FCE) were similar between lambs grazing on either diversified or standard pasture. Average final lamb liveweight off diversified pasture was 4.2 kg higher than off standard pasture. The higher pre-weaning liveweight gain and subsequent greater weaning liveweight off diversified pasture was maintained throughout the summer and autumn.