Determinants of cashmere production: The contribution of fleece measurements and animal growth on farms

https://doi.org/10.1016/j.smallrumres.2008.05.007Get rights and content

Abstract

To identify fleece and animal growth characteristics that are associated with cashmere production, the magnitude and direction of factors affecting cashmere production using fleece and live body weight measurements available to the cashmere producer were modelled. Data was collected from 11 Australian commercial cashmere farms. Following log transformation of clean cashmere weight, the best general linear model for predicting clean cashmere weight included: farm, mean fibre diameter, fibre diameter standard deviation, cashmere fibre curvature and fibre curvature standard deviation, cashmere staple length, clean washing yield, live body weight, live body weight change, and interactions between these parameters. The best general linear model did not include variables for age and sex cohorts. The variance accounted for was 67.6%. The residual standard deviation was 0.115. A majority of the variation regarding clean cashmere production (58%) was related to farm, staple length and mean fibre diameter. To obtain an understanding of how the responses of clean cashmere weight to fleece and growth measurements varied with farm, regression coefficients in the general linear model were modelled as possibly correlated random effects, using REML mixed model analysis. On a typical farm, greater clean cashmere weight was associated with longer staple length, greater mean fibre diameter, greater fibre diameter standard deviation, greater fibre curvature, greater fibre curvature standard deviation and greater live body weight. Farms recorded responses varying from negative to positive for washing yield and live body weight change. It was concluded that fleece characteristics and animal growth (but not age and sex) are primary determinants of cashmere production. However, the way these characteristics affect cashmere production varies from farm to farm.

Introduction

The Australian cashmere industry was established in the late 1970s following the discovery of cashmere on feral goats (Anonymous, 1981). Since then genetic and certain environmental factors impacting on the production and quality of Australian cashmere have been evaluated at research institutes (Holst, 1990, McGregor, 1990, Restall and Pattie, 1991, McGregor and Couchman, 1992, McGregor, 1998). There has however been little cashmere production research since that time (Anonymous, 2001). In Australia, only a few studies regarding the productivity of commercially managed cashmere goats have been published (Couchman and McGregor, 1983, Couchman, 1984, McGregor, 1997). Recently, it has been shown that cashmere production from commercial farms in Australia has not increased substantially over the past 25 years (McGregor and Butler, 2008a).

Since 1989, however there has been widespread culling of cashmere goats in response to decreasing prices, a focus on higher quality fleeces, in particular reduced mean fibre diameter, and the use of more accessible and cheaper objective fleece testing services following the commercialisation of OFDA100 and Laserscan computer-operated fibre testing technology. The new fleece testing technology provides objective measurement of certain important attributes of animal fibres that until recently were known to be important but not feasibly measured. So, for example, Martindale (1945) demonstrated that fibre diameter variation affected processing performance of wool. However the cost of measuring this attribute was prohibitive until computer aided laboratory equipment was developed. While the heritability of cashmere production attributes has been known for some years (Bigham, 1990), and indexes have been developed for the selection of cashmere goats (Pattie and Restall, 1991) there has been little application of these indexes. The development of these indexes predates the widespread availability of objectively measured cashmere fibre attributes such as fibre diameter variability and fibre curvature.

The impact of farm, age and sex on cashmere production and fleece attributes have only recently been quantified for Australian cashmere goats, as these factors are generally the only information available to farmers attending animal sales on or off farms (McGregor and Butler, 2008a). It was found that within individual farms, cashmere production generally increased with age of the animal, as seen with Inner Mongolian Albas goats (Zhou et al., 2003), but the sex of the goats had no effect. This study investigates the fleece characteristics and animal growth determinants of cashmere production within and between farms, and whether these determinants can explain the age effects.

Section snippets

General management

Cashmere goats from 11 farms in 4 different States of Australia (McGregor and Butler, 2008a) were monitored for live body weight (LW; kg) each month (December 2002–June 2003 – just prior to shearing), although some producers were unable to weigh each month (e.g. during mating in autumn). Generally all goats in the flocks were monitored but in some larger flocks 10 randomly selected does from a range of age groups or all their 15-month-old does were monitored. Age at shearing (years) was used as

Results

Data for attributes of the sampled goats are set out in Table 1. The mean, standard deviation, and range in number of cashmere goats per farm were 398, 404, and 70–1200.

Discussion

McGregor and Butler (2008a) found that, within a farm, age but not sex is strongly associated with clean cashmere weight. A major result of the present work is that, at any farm, clean cashmere weight is related to a range of fleece and growth measurements. Once these fleece and growth measurements are taken into account there are no longer any age or sex effects observable. This implies fleece characteristics and growth are primary determinants of cashmere production.

However, as shown by the

Conclusions

Fleece characteristics and animal growth, but not age and sex, are the primary determinants of cashmere production of individual goats within a farm. However, the way these characteristics affect cashmere production varies between farms.

Acknowledgments

The cashmere producers who participated in this project, the Australian Cashmere Growers Association (ACGA), Riverina Fleece Testing Services, Albury, Mark Brims (BSC Electronics Perth) and the Rural Industries Research and Development Corporation, who partly funding this project, are thanked. The manuscript was improved following advice from Associate Editor Professor Greyling and two anonymous referees.

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