Abstract

Triplet-bearing ewes (n = 999) were identified at pregnancy scanning (PS) and randomly assigned to two pasture feeding treatments through to lamb weaning, FeedPlus (FP) and Control (C). FeedPlus ewes were fed according to theoretical requirements based on live weight and a fetal number of three while C ewes were fed as for twinning ewes. Ewe body condition score (BCS) was similar for FP and C ewes at PS (BCS 3). FP ewes had higher BCS than C ewes at set-stocking one month before the mean lambing date (PL, BCS 2.9 ± 0.1 versus 2.6 ± 0.1, P <0.001). Every unit increase in BCS at PS improved litter survival to weaning by 0.33 ± 0.17 of a lamb. An increase of BCS at set-stocking improved litter survival to weaning by 0.45 ± 0.18 of a lamb (P <0.05). Litter weight increased with increasing BCS PL (β= 1.2 ± 0.5 kg/unit BCS, P <0.05). Low BCS ewes (BCS ≤2.5) at PS weaned 3.5 kg less lamb than medium BCS ewes at PS (BCS ≥3) (82.4 ± 1.1 kg versus 85.9 ± 1.4 kg, P <0.05) when rearing triplets. Pre-lamb BCS had a positive effect on lamb weaning weight (β= 1.3 ± 0.6 kg/unit BCS, P <0.05) and on lamb growth rates from birth to weaning (β= 13.5 ± 6.0 g/day per unit increase in PL BCS, P <0.05). The study highlighted the importance of ewe body condition score at PS and PL on triplet ewe performance.

JM, Everett-Hincks, DR Stevens, JM Rendel, TR Smith, and PJ Smith

Proceedings of the New Zealand Society of Animal Production, Volume 73, Hamilton, 126-130, 2013