The effect of length of wool in the manual tautening of skin areas on the live sheep.

Abstract

Comparisons of estimates of fibre population density made by the taut skin method have sometimes to be made among groups of sheep which carry different lengths of fleece at the time of sampling. An experiment was undertaken to determine whether the ability of observers to extend and flatten sampled skin areas in using the above method was affected by differences among lengths of wool equivalent to 12, 9, 6, and 3 months' growth. Observations were made by two observers on three strains of Merino sheep. Biases of up to 3-1/2 per cent. were found in group density comparisons in lengths of , fleece corresponding to growth periods of 6-12 months. If groups with fleece length equivalent to 3 months' growth were also included, biases of up to 7-1/2 per cent. were obtained. Interactions between observers and the various lengths were negligible.