Studies on the variation within the fleece of the characteristics of South African Merino wool. I. Tensile strength

Abstract

The tensile strength of the wool grown on six regions on each of eight sheep was determined. Significant differences between the regions were obtained. In all eases the tensile strength of the belly wool was considerably lower than that of the rest of the fleece. This point was further investigated with six groups of ten sheep each, and it was found that in the case of every group the shoulder sample had a higher tensile strength than the belly sample, the mean difference being highly significant. This finding strengthens the National Wool Growers' Association's recommendation that belly wool should be baled and sold separately from the rest of the fleece. It was further suggested that the belly wool should be excluded in assessing the average tensile strength of the wool of a sheep. Differences in tensile strength between the wool from other regions of the sheep were found to be insignificant, but the highest values were obtained on the shoulder and back and the lowest on the thigh. It was concluded that the shoulder sample should be used for assessing the tensile strength of the wool grown by a sheep, especially in comparisons between different sheep, since differences between the value for the shoulder sample and that of the whole fleece showed the smallest variability. The total correlation coefficient between tensile strength and fibre fineness was -0•4168, a highly significant value.