Effects of very low nutrition during pregnancy on live weight and survival of ewes and lambs

D.C. Smeaton, T.K. Wadams and H-U.P. Hockey

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

Proceedings of the New Zealand Society of Animal Production. 1985, 45: 151-154

Previous work showed that nutrition during pregnancy substantially affected ewe live weight, but that subsequent effects on ewe and lamb survival and weaning weights were small. However, farm advisers have suggested that industry ewes suffer more weight loss than in the above trials with serious consequences for ewe and lamb survival.

These problems were investigated in a trial involving 2 levels of nutrition in mid-pregnancy followed by 3 levels of nutrition in late pregnancy. Average conceptus-free live weights of the 6 groups at lambing ranged from 47.6 to 38.1 kg. The ewes had weighed 53 kg at the start of the trial. Ewes severely under-nourished throughout had an 86% survival during the trial period compared with 94% for the 5 better-fed groups. A line of ewes within the severely under-nourished group had, however, only 80% survival. There was a decline in the percentage of ewes lambing due to very nutrition in mid-pregnancy (78 v 85%). Similarly, lambing percentage of those ewes lambing was affected (126 v 142%). There was some effect on twin lamb survival. Birth weight, particularly twin lambs, was reduced by low nutrition but there was no effect on weaning weight.

Keywords: NZSAPAB; Ewe survival; lamb survival; birth weight; level of nutrition; pregnancy

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Last Updated 03-05-1997