Growth patterns in sheep: wool growth during weight loss and subsequent compensatory growth

Abstract

SummaryWool growth rates (WGR) of individual sheep were measured by a patch-sampling technique, during periods of developmental growth, body-weight loss (which ranged from 21 to 34% of original body weight, at rates between 60 and 150g/day) and subsequent compensatory growth under ad libitum feeding.There was a ‘lag phase’ of about 30 days before WGR appeared to be affected by changes in direction of the animals' growth paths.During body-weight loss WGR declined about 300% more than the percentage change in body weight, with the duration of nutritional stress exerting a greater influence than the rate of body-weight loss.During compensatory growth in body weight, the relationship between WGR and rate of body-weight change was initially negative. Sheep required between 11 and 14 weeks to reach the WGR of 21 g/day found during developmental growth. Compensatory growth of wool did not occur.Duration of the nutritional stress, rather than its severity (as indicated by rate of body-weight loss), was the more important determinant of the time taken for the sheep to regain normal levels of wool growth after the commencement of ad libitum feeding.