A new approach to managing wool production : Measure as You Grow

Abstract

This paper reports the results for three separate experiments used to explore aspects of a new field technique designed to estimate the monthly change in the fibre diameter (FD) and staple length (SL) of flocks; a new tool that would allow woolproducers to adopt a 'measure as you grow' (MYG) approach to managing wool quality. The new technique uses single staples cut on the skin using curved surgical scissors from immediately above the right hipbone of a random sample of sheep each month. The average FD of pooled 2mm snippets cut from the base of each staple is plotted against average SL. The first two experiments established the LSD (95% confidence limits) in FD and SL with increasing number of sheep sampled. In addition, it was established that between sheep variance in SL had the greatest influence on estimated SL. There was no influence of either the person cutting the staple or the person measuring the SL when a standard method was used. The SL of staples cut from above the left hipbone were not significantly different from the right hipbone but the hip staples were 1.5mm shorter than midside staples (P<0.005). In the third experiment, a single staple cut from immediately above the right hipbone of a random sample of 20 sheep each month was used to plot an MYG FD profile for each of 16 commercial flocks. The last sampling for the MYG FD profile was taken within 30 days of shearing. The seasonal variation in FD along the MYG profile was similar to that along hip or midside staples taken from a random sample of 50 sheep at shearing and measured using an OFDA2000. The length weighted mean FD of the MYG FD corrected for the difference in FD between the hip and the midside sites was a reasonable estimate of the flock mean FD. The mean FD of the hip staples was greater than the midside staples but the magnitude of the difference was variable between age groups on the same farm and between the same age and genotype run on different farms. The cost of the MYG service in a commercial wool testing laboratory is $5.50 per flock per month and it was concluded that it could provide an effective management tool for monitoring the effects of changes in grazing pressure on the FD of the wool grown.