Lambing date, ewe live weight and pasture mass effects on ewe and lamb performance during lactation

D.G. McCall, D.C. Smeaton, T.K. Wadams, M.L. Gibbison

Whatawhata Hill Country Research Centre, Ministry of Agriculture and Fisheries, Hamilton

Proceedings of the New Zealand Society of Animal Production. 1986, 46:129-132

Comparisons were made of ewe and lamb weaning weights under 2 lambing dates (6 August and 6 September) with ewes at 2 pre-lambing ewe live weights (52 and 64kg) on 2 levels of pre-lambing pasture mass (approximately 1000 and 400 kg DM/ha) in a 2„ factorial, replicated 4 times. Mixed age Romney and Coopworth ewes were set stocked at 20 ewes/ha from 4 days before lambing until weaning on 21 November. Differential ewe live weights and pasture masses were generated during the winter.

With high pre-lamb pasture masses, early lambing advantaged single and twin lambs by 2.7 and 1.1 kg, respectively at weaning compared to late lambing. The advantages to early lambing at low pasture masses were 1.3 and 0.1 kg, respectively for single and twin lambs. Ewe fleece weight was unaffected by lambing date, but weaning weight of lambs at weaning across all treatments by 1 to 1.4 kg and heavier fleeces by 0.1 to 0.4 kg.

Pre-lamb pasture mass effects on ewe fleece weight and weaning weight were 0.3 and 6kg, respectively and on lamb weaning weights were 3 and 3.3 kg for singles and twins, respectively.

Keywords: NZSAPAB; Lambing date; pasture mass; live weight; fleece weight; ewe; lamb; weaning; nutrition

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Last Updated 18-03-1997