Effect of concentrate supplementation at pasture and inclusion of condensed tannins (Quebracho) in concentrates on lamb performance and faecal egg and worm counts

Abstract

Two studies were undertaken to evaluate the effect of concentrate supplementation at pasture and inclusion of Quebracho on the performance and faecal egg counts of lambs grazing a perennial ryegrass sward from six weeks of age until 5 months of age or slaughter. In experiment 1, from six weeks of age until weaning, lambs were offered no concentrate (NC), low protein (130 g metabolisable protein (MP)/kg dry matter (DM)) concentrate (LP) or high protein (160 g MP/kg DM) concentrate (HP). From weaning until slaughter, lambs were offered 500 g/day of LP or HP concentrate containing either zero Quebracho (T0) or 80 g Quebracho/kg fresh (T80). Prior to weaning, lambs offered LP or HP concentrate had significantly greater weaning live weights (LW), liveweight gains (LWG) from birth to weaning and reduced age at slaughtered compared to those offered NC ( P < 0.001). Protein level had no effect on lamb performance. Lambs offered NC in the pre-weaning period had higher LWG from weaning to the end of the study relative to lambs offered LP and HP concentrate. In the post-weaning period, protein content of the concentrate had no significant effect on age at the end of the study, LWG from birth to the end of the study or carcass characteristics. There was a significant interaction between protein content and level of tannin inclusion on LWG from weaning to the end of the study. Lambs offered LP/T0 concentrate had lower LWG than those offered LP/T80, HP/T0 or HP/T80 concentrates ( P < 0.01). Pre and post-weaning treatment had no significant effect on Strongyle faecal egg counts or total worm counts in the abomasum or small intestine. In experiment 2, from six weeks of age until slaughter, lambs were offered no concentrate (NC), concentrates containing zero Quebracho (LP/T0), concentrate plus 80 g Quebracho/kg fresh (LP/T80) and concentrate plus 100 g Quebracho/kg fresh (LP/T100). The concentrate contained 130 g MP/kg DM. Relative to NC treatment, concentrate supplementation increased lamb LWG from birth to weaning and from birth to the end of the study and reduced age at slaughter ( P < 0.01). Increasing level of tannin inclusion had no significant effect on lamb performance, faecal egg counts or total worm counts in the abomasum and small intestine. Overall in the study faecal egg counts were low and worm counts taken from slaughtered animals were less than 3000 worms per animal. The results of this work indicate that supplementing lambs with concentrates at pasture improved animal performance, but concentrate supplementation and inclusion of Quebracho had no effect on faecal egg counts.