Studies of Comparative Fleece Growth in Sheep I. The Quantitative Nature of Inherent Differences in Wool-Growth Rate

Abstract

Since wool-growth rate is strongly influenced by the plane of nutrition, any measure of inherent wool-producing capacity in the sheep must take this into account, and the relation of these three factors to each other must be known. On general grounds, the relation of wool-growth rate to nutrient intake seems likely to follow the familiar law of diminishing returns which introduces the concept that for each sheep there may be an asymptotic value of wool-growth rate characteristic of the individual. From this and other considerations, it was postulated that these relationships could be described by an equation of the form where y = wool-growth rate, x = nutrient intake rate at or above maintenance levels, Xo = the nutrient intake rate for which y = 0, A = the asymptotic value of y, and k' = a constant dependent on the nutritive qualities of the diet employed: