International Journal of Sheep and Wool Science
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The Sheep Industry- Australia in the Global Scene
\"Australia\'s global trade in meat, wool and live sheep strongly influences strategies that can be used to improve its competitive position and profitability for producers. Growth in the sheep industries is dependent on export markets. Australian sheep meat production is split equally between domestic and export markets. Sheep meat exports from Australia account for about 6% of international trade. Finishing of lambs on grain diets has enabled Australia to efficiently produce higher carcase-weight lambs suitable for the US market. Productivity gains in Australian production can be captured via the sale of extra Australian sheep meats into large international markets. Australia accounts for about 40% of global trade in live sheep, with most markets centred in the Middle East. This trade is split between culturally based demand and supply of low-priced meat in competition with other meats such as chicken. Proximity to the Middle East and clean health status are competitive advantages for Australia. This is a volatile and seasonal market that has a significant impact on Australian sheep prices, particularly in Western Australia, which supplies about 80% of Australia\'s live sheep exports. Reducing volatility in the live sheep market and developing demand for chilled and frozen sheep meat will provide benefits to Australian producers. Australia produces about 30% of total world wool, and is the dominant producer of finer Merino wool, accounting for about two thirds of global production. This dominant global position means that any extra production from Australia is likely to have a direct impact on world price. Productivity gains in fine Merino wool production must be matched with market demand building to sustain global price to enable Australian producers to capture benefits in profitability. Over the past 15 years, China has emerged as the world\'s largest producer of sheep meats and a major producer of wool. China is also a major consumer of sheep meats and wool. \"
Opportunities for the Australian sheep industry
The focus on sheep production, as opposed to \'wool\' and \'meat\' as separate industries, provides stability of income as prices for the two products vary independently. The Sheep CRC initiative of the e-sheep technology platform provides a practical basis for individual animal management and the potential to improve both labour productivity and product quality. An analysis of prices for wool, meat and wheat indicate the importance of product quality in the sheep industry as an achievable means of improving profitability. Given the compatibility of sheep production with cropping and cattle production it is seen as important component of Australia\'s rural economy for many years to come. Future development of the sheep industry should focus on quality improvement for wool and sheep meat to distance these products from commodity markets. It is also essential to transform sheep management through genetic development and application of new technologies to significantly improve labour productivity.
Integration of wool, meat and cropping systems
Scrutiny of existing farm enterprises by farm business managers is increasing in the search for the optimum enterprise mix. It is challenging to identify the optimum enterprise mix in farm businesses because of the complexity of farming systems, price volatility and the difficulty of accounting for risk. Whole-farm modelling enables analysis of the integration of enterprises within a farming system, but requires considerable resources. When models are not available, farm managers who wish to optimise their enterprise mix should consider optimising the use of land, genetic and human resources.
Australian prime lamb- a vision for 2020
\"This article describes the evolution of the prime lamb industry from the 1980s to the present and proposes a path for the future until 2020. In terms of income generated, the industry was floundering in the 1980s, but income increased rapidly after the late 1990s. The increase in the value of the industry was underpinned by a shift to a focus on the consumer demand and implemented by improvements in genetics, farm management and marketing. Current genetic improvement is mainly driven by improvement of carcase weight; future improvements will be derived from a reduction in fatness and an increase in muscle. The influence of genetic selection for leanness and muscle on muscle structure is discussed. It is concluded that selection and management strategies should focus on maintaining muscle with an aerobic metabolism, as this will optimise the organoleptic qualities and nutrient content of meat, which have significant implications for human health. Fat metabolism is discussed in relation to opportunities for maintaining intramuscular fat levels, reducing saturated fat content of lamb and increasing the long-chain omega-3 content of lamb. Future research should focus on improvements in supply-chain efficiency, eating quality, visual appeal, odour and the health attributes of lamb meat. \"
Implementing selection and optimising flock structures in Merino flocks
\"Optimum flock structure and selection practices can improve the profitability of commercial Merino flocks. This report describes several programs that have been developed by the Sheep CRC to facilitate prediction of the potential effects of alternative flock structures and selection practices. These programs include programs that predict the effects of on-farm fibre measurement, terminal sire mating, proportion of wethers in a flock, simultaneous assortment and lamb growth rate. \"
Measurement and selection options for wool and meat production in commercial sheep flocks
Performance measurements in commercial sheep flocks can improve production in the short-term, contribute to genetic gain and can be used to target specific markets and implement precision management. The benefits of performance measurement for enterprises that produce wool, prime lambs or both are discussed. Measurement of fibre diameter may increase income from wool, and measurement of liveweight may increase income from meat; additional benefits can be realised from other performance measurements.
Sheep benchmarking data often show profit differences of more than 50% between average wool producers and the top 20-25% of wool producers. However, interpretation and effective use of such data by consultants and producers is complicated by differences and correlations between performance indicators. Our project was designed in conjunction with benchmarkers to develop a rigorous method for analysis of their data and to determine key performance indicators of the profitability of a variety of sheep production systems. We estimated technical efficiency, which relates all outputs to inputs, and used principal component analysis to identify the most important performance indicators that influence technical efficiency. Productivity for wool enterprises was measured over several seasons, which ranged from very bad to excellent, and varied by up to 30% between farms. The annual improvement in productivity was about 5% for best-practice producers, while the average technical efficiency of less efficient producers declined by 1.4-2.8% per year. Principal components analysis indicated that maximum technical efficiency in south-western Victoria was associated with sheep with slightly finer wool and lower fertility than average, suggesting that emphasis was placed on a higher stocking rate and more wool per ha. Technical efficiency estimates afford producers a more balanced indication of their relative performance than was previously possible. Principal component analysis and regression analysis identify important performance indicators and their relative impacts on technical efficiency, respectively. When used in combination, these analyses represent a powerful tool for diagnosing problems and exploiting opportunities for improved income in Merino wool enterprises.
\"The Australian lamb industry enjoyed considerable success during the past decade. Driven by improved livestock management, product innovation and successful marketing, the financial performance and profitability of the Australian lamb industry during this period compared favourably with that of other Australian agricultural industries. However, challenges continue to confront the lamb industry. As the impact of the current drought declines, lamb production will increase. If significant falls in price are to be avoided, the successful generation of demand that occurred over the past decade must be repeated during the next ten years. This article reviews the successful elements of industry performance since 1995 and identifies the best prospects for market development to 2015. \"
What is the optimum wool-meat enterprise mix?
\"The GrassGroÂ™ model was used to simulate profitability of 14 sheep enterprises at four locations in south-eastern Australia. The simulated enterprises were: Merino wethers (superfine and fine wool); self-replacing Merino ewes (fine and medium wool); dual-purpose Merino ewes (fine and medium wool) joined to terminal sires; prime lamb first-cross ewes joined to terminal sires. A sheep model was also used to compare a self-replacing Merino enterprise with dual-purpose and prime lamb enterprises. GrassGro simulations highlighted that the fine-wool dual-purpose enterprise was the most profitable, followed by the prime lamb, self-replacing Merino and Merino wether systems. From 1999-2003, when a large premium existed for superfine-wool, Merino yearlings with superfine wool were as profitable as the fine-wool dual-purpose enterprise. The sheep model analysis showed that Merino yearlings had slightly greater gross margins than other enterprises when mean wool and meat prices for 1994-2004 were used, but not when prices for meat were high in relation to those of wool (June 2003-May 2004). In the sheep model comparisons, spring lambing resulted in greater gross margins than winter lambing and production of yearlings was more profitable than production of weaners. The dual-purpose Merino meat-wool enterprise is resilient against changes in commodity prices, but the genetic merit (wool production, fibre diameter and liveweight) of ewes purchased or bred should be considered. A prime lamb enterprise, using first-cross ewes, will not necessarily be more profitable than systems using a Merino ewe base, particularly when prices for first-cross ewes are high or when weaning percentages are low. \"
The impact of carcase estimated breeding values on yield and quality of sheep meat
The aims of this study were to investigate the impact of carcase estimated breeding values on carcase size and lean meat yield of lambs and to determine whether nutrition alters these responses. Selection for high estimated breeding values for growth increased carcase size by as much as 4 kg in lambs fed a high plane of nutrition. On a low plane of nutrition, this effect was reduced by 60%, highlighting the importance of nutrition for realizing the potential of this trait. Selection for estimated breeding values for muscling reduced total carcase fatness by 3% in lambs fed at a low plane of nutrition and by 10% in lambs fed at a high plane of nutrition, resulting in an increase in lean meat yield and improved economic returns for sales based on a lean-meat-yield grid. Selecting for estimated breeding values for low fat depth reduced total carcase fatness by 4%; this effect was the same whether lambs were maintained on high or low planes of ! nutrition. Other aspects of meat quality may be influenced by using sires selected for muscling. Meat tenderness may be reduced due to greater connective tissue content, but it is likely that this can be controlled by concurrent selection for growth. Juiciness and flavour may be reduced due to reduced intramuscular fat content, but this can be attenuated by nutritional practices and, in the longer term, by alleviating the negative selection for fatness. Selection for a combination of muscling and growth estimated breeding values in terminal sires is an excellent way to increase both carcase size and lean meat yield of lambs-and to provide greater returns for producers.
Extreme wool production---implications for fitness
\"The research reported here examined factors that affect the production of high-value fleeces grown in harsh environments with particular emphasis on how wool production affects fitness of sheep. Data were derived from genetic resource flocks in New South Wales and Western Australia. Sheep with high genetic values for clean fleece weight had less energy reserves than those with low genetic values for clean fleece weight. The small energy reserves of sheep with high genetic values for clean fleece weight were reflected in lower fatness and lower plasma concentrations of glucose and insulin, the extent of which were sufficient to reduce reproductive turnoff. Selection for low fibre-diameter does not exert these effects, but wool yield is associated with fatness. Yield is important to achieve price premiums for fine wool grown in dusty environments, but the dust content of wool with low dust penetration is surprisingly high. Furthermore, the current method of assessment of dust content based on dust penetration does not reflect the ease of processing. These results indicate that fitness characteristics such as reproduction and fatness should be considered in the breeding objective when selecting for increased fleece weight in harsh environments. \"
Wool and meat genetics--- the joint possibilities
\"Wool and meat contribute to profit in sheep enterprises and both need to be considered in breeding programs. The relative responses expected from selection for a range of traits are presented and the realised responses that have been achieved in Merinos and variation in maternal breeds are illustrated. Knowledge of genetic parameters is required for the development of complex breeding objectives and selection indexes, comprehensive genetic evaluation of animals and the design of effective breeding programs. A review of world literature has highlighted the lack of accurate estimates of genetic parameters, especially for genetic correlations between trait groups. Analyses of a combined dataset from seven Australian Merino resource flocks comprising over 2000 sires and up to 100,000 records for each of various traits have provided accurate estimates of parameters to fill these gaps in current knowledge. The results show that there are no major genetic antagonisms between wool and meat traits and that improvement of both can be achieved by using appropriate selection indexes. Sheep Genetics Australia now provides a common system for genetic evaluation of Australian sheep, including across-flock estimated breeding values for a comprehensive range of traits and several standard indexes for various wool and meat breeding objectives. \"
Optimal development of Australian sheep genetic resources
\"The Australian sheep industry is currently facing changing market conditions in which the main driver of profitability is shifting from wool to meat production. Breeding objectives should respond to such market developments. Because current breeding objectives and indexes were developed separately for terminal sire breeds, maternal breeds and Merinos, price changes are accommodated by changing the weighting of traits. This article considers the development of breed types in relation to each other, taking into account the joint use of these breeds in a crossbreeding system. This article also addresses key issues about development of specialized vs. dual-purpose breeds and how the Merino breed should be developed optimally to maximize future profitability across the Australian sheep industry. A relatively simple model suggested that for a wide range of price ratios between wool and meat, a crossbreeding system with specialized breeds is more profitable than a system based on one dual-purpose breed. Optimal development involves increased growth for meat breeds but increased wool production and no increase in body size for wool breeds that also serve as dams of prime lambs. Reproductive rates of both wool and meat breeds should be increased. \"
Fine, medium and coarse wools are used for different consumer products, each of which is influenced by different key drivers. The key drivers of the fine wool market are economic growth in the major consumer countries, consumer preferences, fabric design and fashion trends. The outlook for fine wool is positive, as the demand for luxury apparel is expected to increase in key markets such as the US, Europe, Japan and Korea over the next 1-5 years. Prospects for medium wool will be influenced by price competition from other fibres, continuing consumer interest in natural fibres and new products such as easy-care garments. A modest recovery in economic conditions should support demand for medium fibre diameter wool in China and potential growth in emerging markets such as India and Eastern Europe. New product applications for interior textiles, particularly upholstery and rugs, could develop new consumer markets, and fibre and product attributes such as easy-care and soft lustre may increase consumer demand for medium wool. Key drivers for coarse wool are economic growth, price and attributes of competing fibres or materials, home ownership, prices and lifestyle trends. Increased home ownership in China and Eastern Europe is a positive driver for the coarse wool market, as is the emerging use of wool upholstery in mass-transport vehicles. After 14 years of turbulence, the Australian wool industry is well positioned to respond directly to global demand for consumer products.
Building Towards an Expert System to Predict Greasy Wool to Top Characteristics
\"This paper develops the concepts towards the development of a rule-based expert system to establish the linkage between greasy wool characteristics and top properties and cover the prediction of top characteristics from greasy wool characteristics. An expert system can only perform as much as what knowledge the experts have come up with. Currently there are gaps in research that render it difficult to develop an expert system to perform all the functionalities related to the prediction of greasy wool to top characteristics, which is why this research looks at it from a conceptual level. This paper says that the total functionality of the greasy wool to top characteristics expert system is obtained by bringing together the functionalities of various sub-expert systems to produce the whole. The various sub-expert systems that have been identified include those that predict yield, colour, style and noil levels, and optimum scouring, carding and combing parameters for a quality wool top. An example to show the structure of an expert system drawn from the identified expert systems is based on the TEAM formulae for prediction of top characteristics.\"
Association of Variation in the Ovine KAP1.1, KAP1.3 and K33 Genes with Wool Traits
\"A candidate gene approach was used to identify genes that may be associated with wool traits in Merino and Merino-cross sheep. Polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis was used to identify sequence variation in the Keratin-Associated Protein (KAP) 1.3 and Keratin Intermediate-Filament protein (KRT) K33 genes (KAP1.3 and K33 respectively), while agarose gel electrophoresis was used to detect length variation in the KAP1.1 gene (KAP1.1). Two half-sib families (SL1, n = 131 and SL2, n = 35) were created for analysis. Wool samples were collected from the mid-side region of the SL1 progeny at 12, 24 and 36 months of age, and the SL2 progeny at 12 months of age. These samples were measured for a variety of commonly assessed wool traits. The genotype of the sire used in SL1 was AB, BD and AB for KAP1.1, KAP1.3 and K33 respectively, while the sire used in SL2 was BC, CJ and DE. In SL1, inheritance of KAP1.1 A was associated (P = 0.036) with a higher yield at 24 months of age compared to the KAP1.1 B. The same trend was also observed for yield at 36 months (P = 0.078). KAP1.3 B was associated (P = 0.045) with whiter wool at 36 months of age compared to the KAP1.3 D. Inheritance of the SL1 K33 B was associated (P = 0.038) with a smaller fibre diameter standard deviation compared to the SL1 K33 A at 12 months of age and it was also associated (P = 0.023) with an increase in mean staple strength compared to the SL1 K33 A at the same age. At 36 months of age, the K33 A was associated (P = 0.019) with whiter wool compared to the K33 B in SL1. In SL2, inheritance of KAP1.1 B was associated (P = 0.006) with increased mean staple length compared to the KAP1.1 C and tended to be associated (P = 0.074) with a decrease in wool brightness compared to the inheritance of the KAP1.1 C. Inheritance of KAP1.3 J allele was associated (P = 0.011) with increased staple length compared with the inheritance of KAP1.3 C and was also associated (P = 0.036) with a decrease in wool brightness when compared with the inheritance of the KAP1.3 C. The inheritance of K33 D was associated with longer staple length (P = 0.029) and tended to be associated with a decrease in wool brightness (P = 0.056) compared to the inheritance of K33 E. Although a narrow study, these results suggest that variation in the genes coding for the KRTs and KAPs have the potential to impact on wool quality and that further investigation of them would be warranted.\"
A particularly attractive area for fine wool producers in the United States is to try to sort fleece lines finer than 18.5µm to take advantage of price premiums and high wool loan deficiency payments (LDP). The objective of this trial was to determine feasibility of building 18.5µm lines of wool to meet contractual requirements using the Optical Fiber Diameter Analyzer (OFDA) 2000. This trial utilized approximately 25,000 head of Rambouillet sheep of varying age over a four year period. Fleeces were sorted into various lines based on the OFDA2000 fiber diameter measurements of individual samples and a pre determined set of fiber-diameter cutoff points. After shearing, bales were weighed and cored and samples were sent to a commercial testing laboratory for determination of yield, fiber diameter, standard deviation, and coefficient of variation. The coefficient of determination (r2) between the estimated fiber diameter of the lines of wool based on the OFDA2000 measurements at shearing and the final core test results was 0.79. OFDA2000 predicted values approximately 0.20µm (range from +.62µm to -0.18µm) coarser than the certified core test. Classing fleeces based on OFDA2000 estimates at shearing produced lines of wool of different diameters in the direction to be expected. The OFDA2000 tended to under-estimate the finer lines (AAA, ALW, and AL) by about 0.3µm and over-estimate coarser lines (A and BL) by about 0.7µm when compared to the certified core test results. Specific 18.5µm lines were successfully identified in 4 of the eight lines. In cases where the targeted µm of < 18.5 was not successfully identified, the difference between the core test µm and the OFDA estimated line µm was low (0.2µm to 0.6µm). These differences were small enough that these lots could be easily combined with a small lot of finer wool to produce an overall lot that would meet contractual requirements. These data suggest that the OFDA2000 can be utilized to sort fleeces at shearing into specific fiber diameter lines of wool. However, its application for this purpose is not as straight forward as desired. Initial settings can be based on predicted OFDA2000 averages but must be modified slightly by the classer based on knowledge of the flock micron history and a percent of fleeces that the classer estimates should be in a particular line.
Cashmere Fibre Diameter and Curvature: Effect of Animal Age and Breedline
Effects of selection for increased mean cashmere fleece value (V) or reduced mean cashmere diameter (F) were assessed in Scottish cashmere goats and compared with a randomly bred line (C). Cashmere samples were collected from, and live weights recorded for, animals of two cohorts (n = 10 per breedline / cohort) at 5, 17 and 29 months (Cohort 1) or 5, 17 and 21 months (Cohort 2) of age. For each cashmere sample, mean cashmere fibre diameter (MFD) and associated CV(%), mean cashmere curvature (deg/mm, MCC) and curvature s.d. (CSD) was calculated. In both cohorts animal weight increased with animal age (P>0.01). In animals of Cohort 1, overall MFD increased from 5 to 29 months of age (15.2 to 16.5 µm; P<0.01) and at 29 months, the MFD of V animals was greater than in F animals (17.8 c.f. 15.1 µm; P<0.01). Overall, MCC decreased between 5 and 29 months of age (57.0 to 52.9 deg/mm; P<0.01). At 5 months of age, the MCC of the F line (60.9) was greater than that of the C (55.8) and V (54.3) lines (P<0.05). Using the 5-month values as a covariate, at 29 months, the MCC was greater in F animals than in C (P<0.05) or V animals (P<0.01). In Cohort 2, in all breedlines, MFD increased between 5 and 21 months (15.0 to17.1 µm; P<0.01), becoming greater in V than either C or F animals (17.8, 16.7, 16.8 µm respectively; P<0.01). The overall MCC was less at 17 and at 21 months than at 5 months of age (51.4, 55.4, 58.8 deg/mm respectively; P<0.01). There was no significant effect of breedline on MCC or in the associated CSD. The overall correlation coefficient of MFD with animal age for all animals between 5 and 29 months (Cohort 1, 0.77, P<0.01) and between 5 and 21 months (Cohort 2, 0.78, P<0.01) was significant but varied with breedline. There was a significant relationship between MCC and MFD but this varied with cohort and breedline. Fibre samples taken at 5 months of age were not suitable for prediction of lifetime cashmere diameter or curvature, particularly of V line goats. It is concluded that fibre diameter and cashmere curvature changes, in response to selection, are affected by animal age, breedline and responses of individual animals; therefore these factors should be taken into account in selection of animals for lifetime performance.
The Role of The University of New South Wales in the Advances in Wool Technology and Sheep Breeding since 1951
The University of New South Wales established a School of Wool Technology in 1951 and more than 600 degrees and diplomas were awarded before the activity was closed down in 1997 because of financial pressures on the University. Despite several changes of name the primary objective continued to be the provision of education and research for the benefit of the pastoral industries that produced wool and red meat. Staff, students and graduates made very significant contributions to the revolution in wool marketing which began with the introduction of objective measurements of wool quality and to advances in animal breeding and genetics. Some of these contributions are reviewed.
Fibre diameter profiles- potential applications for improving fine-wool quality
Experiments were conducted to examine the potential value of measurement and monitoring of fibre diameter changes throughout the wool-growing year for improving wool quality and wool staple strength of fine Merino wool grown in temperate environments of NSW. This work included an on-farm survey of fibre diameter profile patterns, which indicated the relative magnitude of sources of variation in fibre diameter profiles. This provided the starting point for other, more detailed investigations focused on the effects of reproduction on fibre diameter profile, the potential for using grazing management to improve wool quality and utilization of fibre diameter profile data in Merino breeding for the improvement of fine-wool quality. Despite prolonged drought conditions, there was evidence of regional differences in environmental effects on fibre diameter profile characteristics. It seems that less than 400-500 kg green DM/ha is required to suppress fibre diameter in spring sufficiently to reduce mean fibre diameter. However, this pasture benchmark is at best regarded as preliminary as there appear to be several important interacting environmental factors. Phenotypic evidence supports the existing use of coefficient of variation of fibre diameter over either of the components of fibre diameter variation (along or between fibres) as a selection criterion in Merino breeding programs.
A review of genetic parameters for visual traits in Australian Merino genetic resource flocks
The visually assessed traits recorded in seven Australian Merino genetic resource flocks have been reviewed, together with published genetic parameters derived from these data sets. The visually assessed traits were categorised into traits which could be assessed using either standard scoring systems or non-standard scoring systems, as prescribed by the Australian Merino Sire Evaluation Association (AMSEA). For traits which could be assessed using standard scoring systems, genetic parameter estimates are available from the resource flocks for classer grade, wool character, fleece colour, fleece rot resistance, neck and body development, face cover and feet/legs (through front legs and back legs traits). For traits with non-standard scoring systems, genetic parameter estimates are available only for handle, nourishment (through wool condition traits), staple structure (through wool lock traits) and density. The visually assessed wool and conformation traits reviewed appear to be at least moderately heritable. The visually assessed traits generally have small or negligible genetic correlations with clean fleece weight, fibre diameter and body weight. However, the genetic parameters were often estimated with low accuracy and/or derived from data that were based on non-standard scoring systems. Accurate genetic parameter estimates, derived from data based on approved standard scoring systems, are needed to support the services and operations in genetic evaluation provided by Sheep Genetics Australia and AMSEA through Central Test Sire Evaluation. Attention needs to be given to wider implementation of approved standard scoring systems, which are practical to use and cover a greater range of visual traits. This will allow an expansion in the recording of visual traits and subsequent genetic parameter estimation based on the data generated. Important visually assessed traits then will be able to be incorporated into across flock genetic evaluation leading to improved genetic progress in the sheep industry.
Prediction of core bulk using OFDA instruments
The compressibility of a mass of unprocessed wool fibres, termed bulk, is positively related to yarn bulk, and carpet wear resistance and appearance retention of carpets produced from that fibre. As wool bulk is positively related to the dimensional measurements of fibre diameter and fibre curvature it is possible to predict wool bulk from measurements of these characteristics. A series of experiments have shown the best predictor (R2 = 85%) of core bulk to be a model containing loge transformation of mean fibre diameter, mean fibre curvature, (mean fibre curvature)2 and small blob percentage derived from an OFDA100 instrument. If a field measurement of greasy wool was required the best predictor (R2 = 84%) of core bulk was a model containing loge transformation of mean fibre diameter, mean fibre curvature, (mean fibre curvature)2 and small blob percentage derived from OFDA2000 measurements where the staple was restrained in a wire slide. A number of simpler models were capable of producing significant predictions of core bulk (R2 > 80%) using either laboratory or field measurements. The age of the measured sample did not significantly affect its measured core bulk while an assessment of crimp form, as reflected by the ratio of fibre length divided by staple length or the degree of lustre in intact greasy staples, did not improve the prediction model in practical terms.
Relationship between Birthcoat Halo-hair and Medullated Fibres in Merino and Damara Crossbred Lambs Wool
\"OFDA100 was used to assess the levels of medullated fibres in Merino lambs wool and determine relationships with scores for birthcoat halo-hair. For a contrast, wool from Damara x Merino lambs was also measured. There were relatively few objectionable fibres detected in Merino compared with the crossbred wool (means 0.6 to 1.1 v. 98 to 103 per 10,000 fibre snippets). Little relationship existed between the counts of objectionable medullated fibre and the birthcoat halo-hair score. However, halo-hair score was positively correlated with the levels of flat medullated fibres, standard deviation and coefficient of variation of fibre diameter. At this stage, there is no evidence that substantiates a need for specific selection against medullation in Merino wool. However, it is recognised certain crossbreeding situations lead to wool contamination that requires specific bale branding and declaration to warn wool buyers. \"
A Note on the Association of Measurement Precision with Average Fibre Diameter in On-farm Fibre Measurement
Direct and indirect estimates of measurement precision (95% confidence interval) of fibre diameter were assembled from published sources. There was a significant association between precision and average diameter (regression = 0.11±.014 per micron increase in diameter). Appropriate precision values according to average diameter are tabled.
Fractionation of Coloured Substances from Discoloured New Zealand Crossbred Wool
Research with a variety of New Zealand wools showed that the compounds responsible for non-scourable canary yellow discoloration are N-formylkynurenine and kynurenine, together with dityrosine and other unidentified phenolic compounds. This confirms the results of several other research groups who have worked on discoloured Merino wool. These compounds, which can result from microbial- or photo-oxidation of the amino acids tryptophan and tyrosine, are covalently bound within the wool fibre. The compounds were removed from the wool by either chemical fractionation of the wool proteins or enzymatic digestion. Chemical fractionation of the wool proteins indicated that the proteins associated with the yellow discoloration were the high tyrosine type II proteins found in the matrix of the ortho-cortical cells.
Crimp Frequency Effects on Processing Performance of Superfine Wool When Staple Length is Held Constant
\"Four experimental wool processing batches were compiled from hogget fleeces from a superfine wool flock. The batches had essentially equal mean fibre diameter (16.7 mic), coefficient of variation of fibre diameter, staple strength and assessed character. There were two crimp frequency (CF) levels (5.5cr/cm and 9cr/cm) and two specific staple length lots (74mm and 85mm) within each CF group. These lot specifications were achieved by allocating fleeces to lots based on pre-shearing midside wool measurements and shearing certain groups at times pre-determined by wool length growth at the pre-shearing sampling. AWTA guidance testing of the lots indicated this method to be accurate in building experimental lots to tight specifications. These four wool lots were processed through to woven and knitted fabrics. Low CF was generally beneficial in topmaking with approximately 3% lower noil and improved spinning efficiency with (usually) fewer ends down. There was no distinct effect of CF on yarn quality. High CF tended to produce stiffer woven fabrics, but knitted fabrics that were less inclined to pill. These results were in broad agreement with others in the literature where either, the wool was obtained from multiple sources, CF was confounded with SL, or the wools were of broader fibre diameter classes. \"
Modelling Economic Activity in the Australian Sheep Industry
\"Quantitative economic models are regularly used in analysing the economic issues that affect AustraliaÂ’s agricultural industries. The value of quantitative economic models for industry analyses depends on how accurately they represent an industryÂ’s economic activity. This paper describes the development of such a structural econometric model of the Australian sheep industry. The structural econometric procedures on which this model is based provide a high degree of rigour in modelling the economic relationships in the sheep industry. The modelÂ’s specification, estimation and validation processes are described and its intended uses in evaluating sheep industry research are discussed. \"
REVEALING THE GAPS TOWARDS A SOFTWARE SYSTEM TO GUIDE THE OPERATOR IN THE CARBONISING PROCESS
In the different stages of the carbonising process, certain parameters have to be of certain values to ensure the quality of wool at the end of the industrial process. The amount of sulphuric acid to be added to the bowl in order to obtain a particular concentration during acidizing, the level of moisture regain in the wool in the drying stage, the resultant pH after the wool has been neutralised, the percentage loss in mass and the amount of wool obtained after the crushing stages are some of these parameters. This paper describes a first attempt to define the concepts and development of a guideline software that enables the calculation of parameters required to facilitate a smooth carbonisation process as initiated by the operator. This research brings to fore that some of the parameters are subjective and hence cannot be automated. The operator has to make the final decision in such cases. It also brings to fore the fact that there are gaps in the research which have yet to be filled in coming up with formulae to calculate some of the parameters. In the software developed, the whole carbonisation process is broken down into objects, each of which is autonomous software, providing a specialised function. The objects in this software represent the different carbonisation stages of acidising, drying and baking, crushing and dusting and neutralising. These objects are controlled via a menu, which acts as the central control of the software architecture to create a single unit between the various objects.
Re-Use of Fleece-Testing Data to Build Wool Sale Lines
The use of hogget fleece-test data for establishing lines of wool for sale the year after the samples were collected was evaluated by comparing an OFDA2000 device to the use of conventional mid-side testing (Laboratory). Two year-old Merino ewes (n = 673; mean fibre diameter (MFD) 19.6 µm) and wethers (n = 517; MFD 18.2 µm), from the same lamb drop, were shorn and fleece-tested as hoggets and then grazed separately as two flocks during 2001. At shearing in December 2001, individual hogget MFD measurements, adjusted for age, were used as the main criterion to prepare 4 main fleece lines per sex. Greasy fleece weights were also recorded and mid-side samples collected for later testing. Repeatabilities for MFD between hogget and 2 year-old measurements were 0.59 and 0.67 from Laboratory and OFDA2000 testing, respectively. When the sheep were shorn at 2 years of age in December 2001, the MFD of sale lines created from ewe fleeces was an average of 0.5 µm higher when comparing both fleece testing and core testing results with weighted hogget MFD values from the previous year. However the values for fleece sale lines created from wether fleeces were an average of 0.3 µm and 0.4 µm finer when comparing fleece testing and core testing results, respectively, with weighted hogget MFD values. A differentiation of 2.3 and 2.0 µm between the lowest and highest of 4 sale lines for core test MFD was achieved at the December 2001 shearing for the ewe flock and the wether flock, respectively. Based on wool prices achieved in February 2002, objective classing of sale lines, using MFD determinations from the previous year, was estimated to be $0.96 per head more profitable than selling the wool as one main line. In conclusion, the use of an OFDA2000 instrument is equivalent to conventional mid-side testing for establishing lines of wool for sale from 2-year old sheep, when clip preparation is based on individual fleece measurements on samples collected from the sheep in their hogget year.