Effects of body condition score and nutrition in lactation on twin-bearing ewe and lamb performance to weaning

This study investigated the effect of feeding and body condition during late pregnancy and lactation on both ewe and lamb performance until weaning. On day 141 of pregnancy, ewes with a body condition score (BCS) of 2.0, 2.5 or 3.0 were allocated a 'Low', 'Intermediate' or 'High' feeding treatment until weaning at day 79 of lactation. Feeding treatments had no effect on lamb live weight at birth, summit metabolic rate or indices of colostrum intake (P > 0.05). At weaning, lambs born to the High treatment were heavier than the Intermediate treatment, which were heavier than the Low treatment (P < 0.05). Lambs reared by ewes with a BCS of 2.0 were lighter during the lactation period than lambs whose dam had a BCS of 2.5 or 3.0 (P < 0.05). In addition, lambs reared by ewes with a BCS of 2.0 had greater summit metabolic rates and greater survival to weaning than those reared by BCS 3.0 (P < 0.05) but not BCS 2.5 (P > 0.05). There was, however, no effect of feeding treatment on lamb survival to weaning. These results indicate that, within these BCS, benefits could be gained from greater BCS in late pregnancy across all feeding treatments.