The effects of allowance of deferred herbage and concentrate supplementation when offered to ewe lambs, and system of allocation when offered to ewes in late gestation, on animal performance

Abstract

The effects of allowance of extended (deferred) grazed herbage (AEGH) and herbage allocation management (HAM) were studied in ewe lambs (248) and late-gestation ewes (152), respectively, on commercial farms in south-east Ireland in 2005-06. In Experiment 1, which consisted of four treatments, the effects of AEGH (0AE75, 1AE25 and 1AE75 kg DM per head daily) and concentrate supplementation (0AE5 kg per head daily with the 0AE75 kg DM herbage allowance) on lamb performance during the extended grazing (16 December to 3 March) and subsequent grazing (4 March to 11 August) seasons were evaluated. Increasing AEGH increased herbage intake linearly (P < 0AE001) and live weight (P < 0AE001) at the end of extended grazing and the subsequent grazing season. In Experiment 2, single-and twinbearing ewes were allocated to either a conventional (single-and twin-bearing ewes grazed separately) or leader-follower system (twin-and single-bearing ewes, as leaders and followers respectively) of HAM from 30 January to 24 March. The same quantities of herbage were offered daily for each system. System of HAM affected ewe condition score at lambing but did not alter (P > 0AE05) subsequent lamb birth or weaning weights. It is concluded that increasing AEGH to ewe lambs increased liveweight gain during extended grazing and resulted in heavier animals in mid August of the subsequent grazing season. For ewe lambs each 1 kg concentrate DM had the same feed value as 2AE4 kg DM AEGH. Use of a leader-follower system for ewes in late pregnancy did not alter lamb birth weight or subsequent performance.