The accuracy and application of some subjective judgements used in wool research

Abstract

In New Zealand during the last two or three years, a scheme of wool research termed “Wool Survey” which exploits the naturally occurring variation among animals, has been developed on an extensive scale. Visual judgements of count, wool character and various other characteristics of the fleece can be made and recorded without any upset to the wool grower’s shearing or other operations. In this way it has been possible to study the productivity of different breeds, wool types and counts under different environmental conditions and at the same time valuable information on the occurrence of defects has been accumulated. A comparatively large amount of data has been collected in these more or less exploratory researches and the data has been partially analysed. Having found that the system is workable, that a very large amount of data can be collected in a relatively short time and that in the results some very interesting and suggestive differences appear, it is clearly necessary to investigate the accuracy of the various subjective judgments used before drawing final conclusions from the results. The present thesis therefore sets out the results of an investigation of the accuracy of the two main subjective judgements (i.e. count and character) used in extensive wool production research on the survey scale. It then attempts to justify the assumption that greasy fleece weight, in dealing with New Zealand sheep, largely of Romney extraction, is a good measure of scoured fleece weight by the results of small scale scouring tests carried out on wool samples collected in the course of the work. Finally a description of the survey scheme is given, some of the results obtained by its use are presented and their application and the general possibilities of the work are discussed.