Methods of estimating clean-fleece production

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Introduction

The determination of clean content of fleeces is subject to a number of sources of error. Among them, in addition to the method of assessment used, are differences in shrinkage, fiber length, grade, defect, and the climate in the area where the fleece was grown.

The Neale squeeze machine (Neale et al., 1956) has been reported to give accurate estimates of clean-wool content of fleeces. It was felt that it would be desirable to test its accuracy on fleeces showing a wider variation in shrinkage and foreign-matter content than those on which the machine had previously been tested, and to compare its accuracy with that of grease weight and the side-sample method. This report contains the results of tests on wool from California and Texas, each state being represented by several widely varying locations.

Materials and Methods

Fleeces from five flocks in five locations in California and from seven flocks in two locations in Texas were used in the study. Two of the California flocks were represented two years, 1958 and 1959. A total of 728 fleeces was involved. Data on lot size, origin, growth period and climatic information on the locations where the fleeces were grown are presented in table 1.

Three different squeeze machines were used. Six lots were tested on a second machine following the initial test on the first. Both freshly shorn and conditioned wools were tested.

Grease-weight and squeeze readings were recorded for all fleeces. Fleeces from two flocks in California were side sampled during both 1958 and 1959. This sampling procedure consisted of the removal of approximately 100 gm of grease wool from the mid-side of the animal as it was shorn and before the remainder of the fleece was weighed or squeezed. The samples were placed in plastic bags, weighed, scoured and adjusted to standard A.S.T.M. conditions for reweighing. Yield figures based on these samples