The effect of nutritional stress on the wool production potential of strong and fine wool Merino sheep

Abstract

The objective of this study was to investigate the effect of short-term nutritional stress after weaning on the wool production characteristics of fine vs. strong wool producing Merino sheep over the short and medium term. Forty fine wool and 40 strong wool weaner lambs were divided into two equal groups (treatment and control group) each. The treatment and control groups received diets of low and high nutritional value, respectively, for a period of three months. Thereafter the animals were kept for a further 18 months on natural pasture in the Karoo. After the first three months the body weights of the control groups were more than 12 kg heavier than those of their respective stressed groups. However, these differences in body weight were cancelled out by the end of the experiment due to compensatory growth among the treatment animals after alleviation of the nutritional stress. After the three-month stress period the fine wool group produced 42% less wool than their unstressed control group and the strong wool group only 29% less wool than their control group. However, at the end of the study the stressed animals produced the same amount of wool as their respective controls. The most important conclusion from these results is that early nutritional stress did not have a permanent detrimental effect on the wool production potential of fine or strong wool sheep. South African Journal of Animal Science Vol. 35(4) 2005: 273-281