Hogget selection : fleece sampling & measurement analysis

Abstract

Measurements of greasy and clean fleece weight, medullation, and susceptibility to yellow discolouration were taken from up to 100 midside fleece samples. The sheep providing the samples were randomly selected from a flock of 600 Romney/Border Leicester ewe hoggets from a Hawkes Bay property.

The ewe hoggets were studied because of family interest, but the results were analysed as if they were from a ram breeding flock, as their significance is much greater. The selection of ram hoggets by a ram breeder is far more intensive than a commercial farmer's selection of ewe hoggets, primarily because fewer rams are required and they are responsible for about 100 times more lambs than a ewe.

The drought of 1989 was expected to result in wide variation of fleece characteristics throughout the mob. A high correlation however, was still found (as expected) between greasy fleece weight (GFW) and clean fleece weight (CFW).

The top 20 hoggets were selected on GFW and compared with the top 20 ranked on CFW (Figure numbers appeared in both this, the suitability of could be seen, as could the 11). In this example the same tag though ranking changed. From this, the suitability of using GFW for commercial selection could be seen, as could the inaccuracies caused by using GFW for a ram breeder’s programme, in that top performers could easily be excluded from, say, the top ten.

These findings are discussed with reference to their importance to both commercial and ram breeding flocks. Emphasis is placed on accuracy of measurement and consistency of selection methods in both programmes