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Background effects on ewe lambing and weaning performance in well recorded breeding flocks
Amer PR, Sise JA, Jopson NB, Bray AR
Proceedings of the New Zealand Society of Animal Production, Volume 69, pp 115-117, Jun 2009
Proceedings of the New Zealand Society of Animal Production, Volume 69, pp 115-117, Jun 2009
Article class: Conference Presentation
Subject Terms: Growth/development, Mortality/morbidity, Reproduction - female, Twinning/parity
Animal Type: Sheep
Publisher: New Zealand Society of Animal ProductionAbstract
Results of analyses of Sheep Improvement Ltd. (SIL) data (27 flocks and 128,203 lambings) showed a substantial impact of ewes being scanned pregnant but failing to rear a lamb (wet-dry), on weight of lamb weaned at the next lambing. Compared to ewes that reared a lamb at the previous lambing, 'wet-dry' ewes had 0.3 to 0.5 less lambs born per ewe lambing, lamb survival rates were lower by 60 to 70 percentage points and weaning weights up to 0.5 kg lighter per lamb weaned. These effects compounded into 30 to 40 kg less weight of lamb weaned per ewe. The failure to rear part of a litter, such as one lamb of a set of twins, had less effect on performance at next lambing and weaning, than loss of the whole litter. Those ewes that previously gave birth to three lambs weaned 4 kg less lamb weight than ewes that previously gave birth to singles, after allowing for their higher genetic drive for prolificacy. A modest but significant effect of previous litter size was observed on weight of lamb weaned within each litter size category. Lamb survival was observed to be 2% lower (P <0.01) for twin ewes that had failed to rear one of their two lambs, compared with those that had reared both in their previous lambing.The whole of the literary matter of the Proceedings of the New Zealand Society of Animal Production is copyright New Zealand Society of Animal Production, Downloading this article signifies agreement with the terms and conditions of electronic access.
