Phenotypic associations with fibre curvature standard deviation in cashmere

Small Ruminant Research 91 (2010) 193–199

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Phenotypic associations with fibre curvature standard deviation in cashmere B.A. McGregor a,∗ , K.L. Butler b a b

Livestock Production Sciences, Future Farming Systems Research Division, Department of Primary Industries, Attwood, Victoria 3049, Australia Biometrics Unit, Future Farming Systems Research Division, Department of Primary Industries, Werribee, Victoria 3030, Australia

a r t i c l e

i n f o

Article history: Received 18 January 2010 Received in revised form 18 March 2010 Accepted 22 March 2010 Available online 24 April 2010 Keywords: Crimp Mean fibre diameter Farm Fibre testing Fibre classing Selection

a b s t r a c t Cashmere fibre curvature (crimp) impacts on the softness and quality of cashmere textiles, the efficiency of cashmere processing and cashmere production. This study investigated the relationship between cashmere fibre curvature standard deviation (FCSD) and other fleece attributes, and how this relationship differs with animal and farm attributes, for 10 commercial cashmere flocks in Australia. Data was analysed using general linear model analysis. Nineteen parameters were recorded for 1168 goats. Following log transformation, the best model for FCSD included farm, goat age, mean fibre diameter, fibre curvature, fibre diameter standard deviation, cashmere yield, cashmere staple length and live weight and the interactions between these terms. The percentage variance accounted for was 82%. Mean fibre diameter and fibre curvature accounted for 55% of the variation in FCSD and farm accounted for 41% of the variation. Cumulatively mean fibre diameter, fibre curvature and farm accounted for 75% of the variation existing in FCSD. For the other terms, age added 2% and the remaining measurements a further 5% to variation accounted for by the best model. Environmental (farm-effects) on FCSD are large and may explain the difficulties cashmere growers experience when they evaluate cashmere goats. Increasing the fibre curvature of cashmere was associated with an increase in cashmere FCSD, but for some combinations of farm and MFD the increase in FCSD was ≈35◦ /mm while with other combinations the increase was ≈5◦ /mm as fibre curvature increased. At a given fibre curvature the response of FCSD to mean fibre diameter differed substantially between farms, from strong negative to strong positive. Increasing cashmere yield from 20 to 55% was associated with decline in FCSD. Increasing fibre diameter SD from 3 to 5 ␮m increased FCSD by 6◦ /mm, increasing staple length and live weight were associated with small declines in FCSD. There was strong evidence of an age effect that differed with farms, but there were few clear cut trends in FCSD with increasing age. The results suggest that farm based influences are affecting the point at which fibre keratinisation is completed and thus influencing the variation in FCSD. We conclude that, because the differences between farms in the relationship been fibre curvature standard deviation, mean fibre diameter and fibre curvature are great, it is unlikely that crimp rate and crimp definition will be good indicators of cashmere fineness across farms. Crown Copyright © 2010 Published by Elsevier B.V. All rights reserved.

1. Introduction

∗ Corresponding author. Current address: Deakin University, Geelong, Victoria 3217, Australia. Tel.: +61 3 52 273 358. E-mail address: [email protected] (B.A. McGregor).

Cashmere exhibits single fibre crimping, which can be reliably measured as fibre curvature. The relationship between crimp frequency and fibre curvature of cashmere is quite strong, even though it covers a different range of

0921-4488/$ – see front matter. Crown Copyright © 2010 Published by Elsevier B.V. All rights reserved. doi:10.1016/j.smallrumres.2010.03.014

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Table 1 State, climate zone and number of does and wethers of each age for each farm, that were included in the analyses. Farm

State

Climate zone

Rainfall (mm) a

Sex b

2002–2003

Mean

2

Vic

Wheat-sheep

364

443

3 4 5

NSW WA Vic

High rainfall Wheat-sheep Wheat-sheep

507 282 261

688 332 551

6 7 8 9 10

Qld NSW NSW NSW NSW

High rainfall High rainfall High rainfall High rainfall High rainfall

611 951 477 478 902

807 1302 848 694 1290

11

Vic

High rainfall

463

811

a b

Age of goat (years) 1

Doe Wether Doe Doe Doe Wether Doe Doe Doe Doe Doe Wether Doe Wether

9 9 – – – – – 20 – – 19 26 34 31

2 10 – 16 51 307 4 41 25 23 31 21 4 21 6

3

4

5

6

7

8–10

11–13

9 – 20 42 – – 25 16 16 45 27 5 9 6

8 – 20 – – – 13 10 21 28 2 – 19 3

10 – – – – – 5 – – 25 11 – 10 2

11 – – – – – 4 – – – 7 – 4 1

– – – – – – 3 – – – 12 – – –

– – – – – – – – – – 2 – 2 –

– – – – – – – – – – – – 7 –

For the 12-month period July 2002 to June 2003. The long-term mean rainfall (all locations > 50 years).

values to those that have been observed in wool. Raw cashmere of different origins exhibits different fibre curvature and fibre crimp forms. Eleven different forms of cashmere fibre crimp, including straight fibres, have been described and the occurrence of these crimp forms vary with the origin of the raw cashmere (McGregor, 2000, 2001, 2007). The amount of fibre curvature of Merino wool has commercial importance although less important than mean fibre diameter, staple length and clean washing yield (Anon., 1973). Fibre curvature affects the textile processing and performance of cashmere and wool knitwear (McGregor and Postle, 2002, 2004, 2007, 2008, 2009; Wang et al., 2006). In cashmere, lower fibre curvature has been associated with reduced efficiency of textile processing and the production of shorter cashmere (McGregor and Butler, 2008a) and with increased softness, as measured by reduced resistance to compression, in dehaired cashmere (McGregor, 2000, 2001, 2004). Fibre curvature standard deviation (FCSD) is a measurement that has only become available since the commercialisation of the OFDA100TM and Sirolan LaserscanTM computer operated fibre testing equipment, and is fre-

quently not measured. However, in Merino wool, FCSD has been shown to affect two important properties of the wool. Firstly, increasing the variation of fibre curvature (higher FCSD) has been shown to be negatively correlated with staple crimp definition. In other words, wool staples with good crimp definition have low variation in fibre curvature (Swan, 1994). Staple crimp definition is a measure of the clarity or dominance of a particular crimp waveform within the staples. “These effects are thought to be mediated through fibre entanglement, the poorer definition wools being in a sense being more entangled which predispose them to further entanglement during scouring” (Swan, 1994). Secondly, at a given mean fibre diameter, an increase in FCSD is associated with a reduction in felting propensity (Greeff and Schlink, 2002). Hynd et al. (2009) indicated that crimp is the result of two different factors which can override each other. They concluded that fibre crimp is caused predominantly by asymmetric cell division in follicles that are highly curved and then modulated by the point at which keratinisation is completed. This means that even highly asymmetric follicles may produce a straight fibre if keratinisation is

Table 2 Mean, standard deviation (SD) and range in measured attributes of sampled cashmere goats from 10 farms (n = 1168). Variables

Mean

SD

Minimum

Maximum

Age of goat (years) Live weight (kg) Initial live weight, December or January Final live weight, May or June Change in live weight (Initial–Final)

2.7

1.5

1

13

25.6 27.6 +2.0

9.2 8.9 4.7

5 8.6 −14.7

68.7 69.4 +18.5

Greasy fleece weight (g) Clean washing yield (%w/w) OFDA cashmere yield (%w/w) Clean cashmere yield (%w/w) Clean cashmere weight (g) Staple length (cm) Mean fibre diameter (␮m) Fibre diameter SD (␮m) Fibre diameter coefficient of variation (%) Fibre curvature (◦ /mm) Fibre curvature SD (◦ /mm)

397 90.0 37.7 33.9 137 8.7 16.5 3.68 22.5 48 33

112 74.0 11.6 10.8 31 2.5 13.0 2.57 14.8 25 20.0

910 98.7 86.4 60.9 389 16.0 22.0 5.56 36.4 72 59.5

123 4.4 10.6 9.1 62 2.1 1.6 0.41 2.8 8.8 6.0

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Table 3 A list of the statistical significance of rejected and included terms in the final model for fibre curvature. Adjustment to final model

F-value

Degrees of freedom

P-value

Terms retained log FDSD Interaction of Age Factor and Farm Square of MFD differs with Farm Square of OFDACMyld Square of FC OFDACMyld differs with Farm SL Product of FC and MFD differs with farm Square of Initial LW

152.28 5.52 4.98 15.84 12.46 2.99 9.49 3.24 3.92

1, 1065 26, 1065 9, 1065 1, 1065 1, 1065 9, 1065 1, 1065 9, 1065 1, 1065

8.5 × 10−33 6.9 × 10−17 1.4 × 10−6 7.4 × 10−5 0.00043 0.0016 0.0021 0.0068 0.047

Terms rejected Clean cashmere weight CWY Fibre diameter coefficient of variation Greasy fleece weight Live weight change Sex effect Initial LW coefficient differs with Farm log FDSD coefficient differs with Farm OFDACMyld coefficient differs with Farm SL coefficient differs with Farm FC coefficient differs with Age Factor Initial LW coefficient differs with Age Factor log FDSD coefficient differs with Age Factor MFD coefficient differs with Age Factor OFDACMyld coefficient differs with Age Factor SL coefficient differs with Age Factor Product of FC and Square of MFD Product of Square of FC and MFD Product of FC and Initial LW Product of FC and log FDSD Product of FC and OFDACMyld Product of FC and SL Product of FDSD and Initial LW Product of MFD and Initial LW Product of MFD and log FDSD Product of MFD and OFDACMyld Product of MFD and SL Product of OFDACMyld and log FDSD Product of OFDACMyld and Initial LW Product of OFDACMyld and SL Product of SL and Initial LW Product of SL and log FDSD Square of FC coefficient differs with Farm Square of log FDSD Square of SL Cube of FC Cube of Initial LW Cube of MFD Cube of OFDACMyld

1.51 3.02 0.54 0.38 0.53 1.71 1.32 1.35 1.35 0.72 1.39 0.50 1.48 1.13 1.05 1.50 0.21 0.01 1.73 3.16 0.30 0.90 0.24 0.42 0.00 0.16 0.78 0.02 0.59 0.01 1.92 0.02 1.60 1.28 0.00 1.08 0.06 0.06 1.91

1, 1057 1, 1063 1, 1064 1, 1064 1, 1059 1, 1064 10, 1055 9, 1056 9, 1056 9, 1056 8, 1057 8, 1057 8, 1057 8, 1057 8, 1057 8, 1057 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 9, 1056 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064 1, 1064

0.22 0.082 0.46 0.54 0.47 0.19 0.21 0.21 0.21 0.69 0.20 0.86 0.16 0.34 0.69 0.15 0.65 0.91 0.19 0.076 0.59 0.34 0.62 0.52 0.95 0.69 0.38 0.90 0.44 0.91 0.17 0.90 0.11 0.26 0.95 0.30 0.81 0.81 0.17

sufficiently delayed, as is the case in deficiencies of zinc and copper, or when keratinisation is perturbed by transgenesis (Hynd et al., 2009). In this model FCSD is likely to be primarily influenced by the modulation which is likely to a have a low genetic, and thus a large nongenetic (nutrition, physiological state, climate zone, etc.), component. With Australian cashmere goats, we have found that clean cashmere weight increases with decreasing FCSD but the difference between farms in the magnitude of the response was large (McGregor and Butler, 2008b). This work indicates therefore that, at least on many farms, more uniform cashmere fibre crimp is a driver of increased cashmere production. In the absence of any genetic information regarding FCSD, and in view of the potential for using

FCSD as a screener for cashmere quality, this study investigates which phenotypic factors are associated with the variation in FCSD of cashmere from commercial flocks in Australia. 2. Materials and methods 2.1. General management The data set and approach are the same as described in our earlier investigations (McGregor and Butler, 2008c, 2009a,b). Cashmere goats from 10 farms in 4 different States of Australia were monitored for live body weight (LW; kg) each month from December 2002 (initial LW; kg) until June 2003 (final LW; kg), just prior to shearing (Table 1). At shearing, the greasy fleece was weighed and grid-sampled. Cashmere fibre staple length was measured after shearing. The shearing process at the different farms occurred between 31st May and 7th August 2003. Farms were classi-

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fied into two (High Rainfall zone, Wheat-sheep zone) of the three climatic zones following the official Australian method (Alexander and Williams, 1973; ABARE, 2006). No farm was present in the Pastoral zone. Rainfall records were obtained from official recording stations in accordance with the Australian Bureau of Meteorology standards (Anon., 2009). 2.2. Fibre testing Fleece samples were sent to a commercial fibre-testing laboratory. Following aqueous scouring to determine the clean washing yield (CWY; %w/w), (IWTO-19, 1995), all samples were cored twice, conditioned and for each sub-sample over 6000 counts were recorded using the OFDA100 (IWTO-47, 2002) and the average determined. Measurements recorded were the mean fibre diameter (MFD; ␮m), fibre diameter standard deviation (FDSD; ␮m), fibre curvature (FC;◦ /mm) and fibre curvature standard deviation (FCSD;◦ /mm), and fibre diameter distribution. OFDA cashmere yield (OFDACMyld; %w/w) was determined using fibre diameter distribution profiles obtained during the measurement of MFD and using a fibre diameter cut-off of 35 ␮m for cashmere (Peterson and Gheradi, 1996). The clean cashmere yield (CCMyld; %w/w) was determined as: CWY × OFDACMyld. Further details of fibre testing are provided elsewhere (McGregor and Butler, 2008a). 2.3. Statistical analysis The final database for fibre attributes (n = 1168 does and wethers (castrated male)), included wethers from 4 farms (n = 97). A parsimonious general linear model with normal errors (Payne, 2007) was developed to determine the relationship between the logarithm of cashmere fibre curvature standard deviation of individual goats and other fibre measurements, live weight measurements, farm, age of the goat and sex of the animals. The best model was developed with terms being added or rejected on the basis of F-tests (P < 0.05). Fibre curvature standard deviation was log transformed prior to analysis to avoid the amount of residual variation increasing as the mean increased (Sokal and Rohlf, 1995). Back transformed predicted means of various traits, adjusted for other terms in the model on the logarithmic scale, are presented for 2-year-old goats at the 2-year-old average of the traits used in the adjusting terms. For FDSD, this averaging was carried out after a log transformation of FDSD. Equal weighting for farms was used for predicted means adjusted for farms. Least squares models, that included only prescribed subsets of the parameters in the parsimonious model, were fitted and compared using percentage variance accounted for (Payne, 2007).

3. Results Considerable variability was recorded in the measured attributes, including fibre curvature and FCSD (Table 2). 3.1. Final model for cashmere fibre curvature The final general linear model was of the form (Table 3): Log10 (FCSD) = ˛ + ˇ1 MFD + ˇ2 (MFD)2 + ˇ3 FC + ˇ4 (MFD × FC) + 1 (FC)2 + 2 log10 (FDSD) + 3 initial LW + 4 (initial LW)2+ ˇ5 OFDACMyld + 5 (OFDACMyld)2 + 6 SL where the intercept parameter ˛ differs between combinations of farm and age, ˇ1 , ˇ2 , ˇ3 , ˇ4 and ˇ5 differ between the farms but not age, and  1 ,  2 ,  3 ,  4 ,  5 and ␥6 do not differ with farm or age. The percentage of variance accounted for was 82.4% and the residual standard deviation recorded was 0.0315.

Fig. 1. The influence of fibre curvature (FC) and mean fibre diameter at each farm on fibre curvature standard deviation (FCSD). Symbols for mean fibre diameter curves: , 14 ␮m; 䊉, 16 ␮m; , 18 ␮m; , 20 ␮m.

3.2. Effect of fibre curvature, mean fibre diameter and farm Increasing the fibre curvature of cashmere was associated with an increase in cashmere FCSD (Fig. 1). The increase in FCSD depended upon the mean fibre diameter and farm. For some combinations of farm and MFD the increase in FCSD was ≈35◦ /mm while with other combinations the increase was ≈5◦ /mm as fibre curvature increased. Generally the rate of increase (slope) in FCSD was less for finer cashmere and the slope increased as mean fibre diameter increased (Fig. 1). There were differences between farms in the relative FCSD for cashmere with the same mean fibre diameter. For farms 7, 8, 9, 10 and 11 the finest cashmere had the highest FCSD, whereas for farms 4 and 6 the finest cashmere had the lowest FCSD. Farms 2, 3 and 5 were intermediate between these positions. 3.3. Effect of OFDA cashmere yield at different farms Increasing OFDA cashmere yield was associated with a curvilinear decline in cashmere FCSD but for some farms this change was only small (Fig. 2). Increasing OFDA cashmere yield from 20 to 55%, where most farms were rep-

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in FCSD with increasing staple length and initial live weight (Fig. 3b and c). 3.5. Effect of age within farms There is strong evidence of an age effect that differed with farms, even after allowing for the effects of measured traits (Table 3). Although the effects of specific ages are sometimes of reasonable magnitude, there are few clear cut trends in FCSD with increasing age (Fig. 4). 3.6. Variance accounted for by different attributes

Fig. 2. The influence of OFDA cashmere yield on cashmere fibre curvature standard deviation (FCSD) for each farm. Symbols: farm 2, ; farm 3, +; farm 4, ; farm 5, ; farm 6, ; farm 7, 䊉; farm 8, *; farm 9, ♦; farm 10, ; farm 11, .

resented, decreased FCSD ≈5◦ /mm. There was little change in FCSD above cashmere yields of 55%. 3.4. Effect of fibre diameter SD, staple length and initial live weight Over the range in fibre diameter SD from 3 to 5 ␮m, FCSD increased about 6◦ /mm (Fig. 3a). There were small declines

The major share of variation, 75.1% of total variation and 91% of the variation accounted for by the model, could be attributed to differences between farms, mean fibre diameter and fibre curvature (Table 4). 4. Discussion The major share of the variation in fibre curvature standard deviation of Australian cashmere is associated with mean fibre diameter, fibre curvature and farm. Mean fibre diameter and FC accounted for 55% of the variation in the logarithm of FCSD and farm alone has accounted for 41% of the variation. Cumulatively, the mean fibre diameter, FC and farm accounted for 75% of the variation in FCSD, with age adding 2% and OFDA cashmere yield, initial live

Fig. 3. The influence on cashmere fibre curvature standard deviation (FCSD) of (a) fibre diameter standard deviation (FDSD), (b) staple length and (c) initial live weight of cashmere goats.

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Fig. 4. The influence of age for each farm on fibre curvature standard deviation (FCSD). Symbols: farm 2, ; farm 3, +; farm 4, ; farm 5, ; farm 6, ; farm 7, 䊉; farm 8, *; farm 9, ♦; farm 10, ; farm 11, .

weight, fibre diameter standard deviation and staple length combined adding a further 5% in the variation. It is not surprising that FCSD generally increases with increasing FC in the same way that MFDSD generally increases with MFD in Merino sheep. For instance, in most published studies with Merino sheep it has been found that the phenotypic and genetic correlation between mean fibre diameter and coefficient of variation of fibre diameter is small (Beattie, 1961, 1962; Gregory, 1982; James et al., 1990; Safari and Fogarty, 2003), and hence the phenotypic and genetic correlation between mean fibre diameter and standard deviation of fibre diameter must be positive. The surprising result is the extent that the strength of the relationship between FCSD and fibre curvature differs with both farm and mean fibre diameter. This suggests that farm based influences are affecting the point at which fibre keratinisation is completed and thus influencing the variation in FCSD. This result implies that it will difficult to make general rules for selecting simultaneously for both fibre curvature and FCSD, and thus presumably for selecting simultaneously for both crimp rate and crimp definition. The only generalisation that can be made from the results is that the relationship between FCSD and fibre curvature is weaker with finer cashmere. This suggests that it will be easier to move towards higher curvature, lower

fibre curvature variation cashmere if the foundation goats already produce finer cashmere. At a given fibre curvature the response of FCSD to mean fibre diameter differed substantially between farms, from strong negative to strong positive. The difference between farms in the relative FCSD for cashmere of different mean fibre diameter, at the same fibre curvature, will be related to genetic and environmental differences between farms, but the relative importance of environment and genotype is unknown. The farms where the finest cashmere had the highest FCSD, namely farms 7, 8, 9, 10 and 11, were all located in the High Rainfall Zone, and suffered serious rainfall deficiencies (Table 1). However other farms with a serious rainfall deficiency had different responses, namely farms 3 and 5. Traditionally cashmere fibre classification on-farm and sorting prior to sales has been based on the subjective methods used for wool classing where the degree of fibre crimp and crimp uniformity are used as a major guide for estimating the fibre diameter of sale lots (Anon., 1997). McGregor and Butler (2009a) concluded “Using cashmere fibre curvature (crimp frequency) as a tool for changing mean fibre diameter or selecting homogenous batches of fibre for sale will be reasonably effective within a farm, but is not a reasonable indicator and predictor of mean fibre diameter differences between farms”. The present study further indicates that fibre curvature (crimp frequency) and FCSD (crimp definition) combined will also not be a reasonable predictor of mean fibre diameter between farms. FCSD, in conjunction with fibre curvature, could be used as a tool for changing mean fibre diameter within a farm, but only if the direction of response between mean fibre diameter and FCSD was already known. Increasing OFDA cashmere yield from 20 to 55% was associated with decline in FCSD, but little response was observed at higher cashmere yields. This result is in accordance with relatively improved goats having both a higher yield and little change in fibre curvature. Similarly, the small decline in FCSD with increases in staple length has been observed previously, and is also in accordance with relatively improved goats having higher production and staple length (McGregor, 2003; McGregor and Butler, 2008c). Increasing the fibre diameter standard deviation was associated with an increase in FCSD. This seems sensible

Table 4 Variance in the logarithm of cashmere fibre curvature standard deviation accounted for by terms involving farm, fibre diameter, fibre curvature age and other measurements. Terms in model involving

Residual S.D.

Residual variance

% variance accounted for by model

None MFD and FC MFD, FC, FDSD, OFDACMyld and SL MFD, FC, FDSD, OFDACMyld, SL and initial LW Farm Farm and age Farm, MFD and FC Farm, age, MFD and FC Farm, MFD, FC, FDSD, OFDACMyld and SL Farm, age, MFD, FC, FDSD, OFDACMyld and SL Farm, MFD, FC, FDSD, OFDACMyld, SL and initial LW Full model

0.0751 0.0501 0.0459 0.0455 0.0577 0.0540 0.0375 0.0357 0.0337 0.0316 0.0333 0.0315

0.0056 0.0025 0.0021 0.0021 0.0033 0.0029 0.0014 0.0013 0.0011 0.0011 0.0011 0.0010

0 55.4 62.7 63.2 40.9 48.3 75.1 77.4 77.9 82.3 80.3 82.4

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since both FC and MFD are both primarily determined by skin follicle activity and nutrition (Hynd et al., 2009). With the goats used in the present study it has been shown that increasing initial live weight results in increasing cashmere production and reduced fibre curvature (McGregor and Butler, 2008c), but changes to initial live weight had little effect on FCSD. There were differences between age of goats in FCSD within farms, but these effects were inconsistent between farms and did not generally change predictably as age of goat increased within a farm. We suggest that much of these effects are likely to be due to either the nutritional history of cohorts of goats or the specific selection practices at individual farms, rather than effects of age of goat per se. If FCSD does measure variation in fibre curvature, fibre disorder and fibre entanglement, as Swan (1994) reported for Merino wool, then variation in FCSD might reasonably be expected to affect cashmere dehairing performance. However FCSD was not related to the dehairing performance of cashmere used in the present study (McGregor and Butler, 2008a). 5. Conclusions The major factors affecting cashmere fibre curvature standard deviation were mean fibre diameter, fibre curvature and farm. Because the differences between farms in the relationship been fibre curvature standard deviation, mean fibre diameter and fibre curvature are great, it is unlikely that crimp rate and crimp definition will be good indicators of cashmere fineness across farms. Acknowledgments The cashmere producers who participated in this project; the Australian Cashmere Growers Association (ACGA); Mrs. Val Park, 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. References ABARE, 2006. Agriculture in Australia. In: Agricultural Economies of Australia and New Zealand: Past, Present, Future. Australian Bureau of Agricultural Economics, Canberra, Australia, 57 pp. Alexander, G., Williams, O.B. (Eds.), 1973. The Pastoral Industries of Australia. Sydney University Press, Sydney, p. 573. Anon., 1973. In: Andrews, M.W., Downes, J.G. (Eds.), Objective Measurement of Wool in Australia. Technical Report of the Australian Wool Board’s Objective Measurement Policy Committee. Australian Wool Corporation, Melbourne, pp. 1.1–1.6. Anon., 1997. Guide to clip preparation. Cashmere Aust. 19 (1), 1–23. Anon., 2009. Historic climate data. http://www.bom.gov.au/ accessed 14 October 2009. Beattie, W., 1961. Relationships among productive characters of merino sheep in north-western Queensland. 1. Estimates of phenotypic parameters. Qld. J. Agric. Sci. 18, 437–445. Beattie, W., 1962. Relationships among productive characters of merino sheep in north-western Queensland. 2. Estimates of genetic parameters, with particular reference to selection for wool weight and crimp frequency. Qld. J. Agric. Sci. 19, 17–26. Greeff, J.C., Schlink, A.C., 2002. Genetic variation of Merino wool felting. In: Proc. 7th World Con. Genet. Appl. Livest. Prod., Montpellier, France.

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