Crimp Frequency Research Articles

Understanding the difference in softness of Australian Soft Rolling Skin wool and conventional Merino wool

Softness is one of the key elements of textile comfort and is one of the main considerations when consumers make purchasing decisions. In the wool industry, softness can reflect the quality and value of wool fibers. There is verifiable difference in subjective softness between Australian Soft Rolling Skin (SRS) wool and conventional Merino (CM) wool, yet the key factors responsible for this difference are not yet well understood. Fiber attributes, such as crimp (curvature), scale morphology, ortho-to-cortex (OtC) ratio and moisture regain, may have a significant influence on softness performance. This study has examined these key factors for both SRS and CM wool and systematically compared the difference in these factors. There was no significant difference in the crimp frequency between these two wools; however, the curvature of SRS wool was lower than that of CM wool within the same fiber diameter ranges (below 14.5 micron, 16.5–18.5 micron). This difference might be caused by the lower OtC ratio for SRS wool (approximately 0.60) than for CM wool (approximately 0.66). The crystallinity of the two wools was similar and not affected by the change in OtC ratio. SRS wool has higher moisture regain than CM wool by approximately 2.5%, which could reduce the stiffness of wool fibers. The surface morphology for SRS wool was also different from that of CM wool. The lower cuticle scale height for SRS wool resulted in its smoother surface than CM wool. This cuticle height difference was present even when they both had similar cuticle scale frequency.

Effect of housing and nutritional interventions during winter on wool attributes of Corriedale sheep.

There are several factors that can directly or indirectly influence wool quality and quantity in sheep, the main elements being genetic and environmental factors. An experiment was conducted to assess the effect of different management/housing interventions during winter on wool quality and yield in Corriedale ewes. Forty healthy pregnant ewes were selected and divided into four groups (G1, G2, G3, G4) based on their body weight and parity. Throughout the study period, the groups G1 and G3 were reared inside the shed, while G2 and G4 were reared in an open shed with four-sided wire fencing and a roof shelter for direct rain/snow protection. The basic ration of all the four groups consisted of 1.25kg roughage/head/day and 500g concentrate/head/day. G3 and G4 were fed additional concentrate @ 100g/head/day. Significant differences were observed in the crimp frequency, fibre diameter, fibre length and medullation percentage. G2 and G4 showed significantly (P < 0.05) higher fibre diameter but lower crimp frequency. Also, medullation percentage was significantly (P < 0.05) higher for G2. However, the studied rearing systems showed no significant differences for wool yield, staple length, scouring yield and burr content. The study concludes that the wool quality parameters observed in sheep, exposed to cold environment, meet most of the requirements of textile sector and thus can be reared in open houses without any adverse effects.

Fluid structure interaction study on straight and undulated hollow fibre hemodialyser membranes

In hemodialysis therapy, the dialyser is subjected to blood flow continuously for several hours and is also being reused; the stress experienced by the fibres owing to blood flow is of utmost importance because it reflects on the mechanical stability of the membrane. It is tedious to study the stress experienced by an individual fibre in real-time; computer aided techniques enables to gain better insights about the load bearing capacity of the membrane. A finite-element strategy is implemented to study the effect of flow induced stress in hemodialyser membrane. A 3D model of the membrane was developed in straight and undulated (crimped) fibre orientations. Fluid structure interaction study was conducted to analyse the stress distribution due to varying blood flow. It is observed that in both the fibre orientations, the stress varies inversely with the blood flow rate. The effect of varying the length of the fibre, wall thickness and crimp frequency is also studied. From the analysis it is found that the crimped fibres experiences less stress compared to straight fibre. Such analysis aids to predict and evaluate the performance of the hemodialyser membrane.

Tendon Biomechanics and Crimp Properties Following Fatigue Loading Are Influenced by Tendon Type and Age in Mice.

In tendon, type-I collagen assembles together into fibrils, fibers, and fascicles that exhibit a wavy or crimped pattern that uncrimps with applied tensile loading. This structural property has been observed across multiple tendons throughout aging and may play an important role in tendon viscoelasticity, response to fatigue loading, healing, and development. Previous work has shown that crimp is permanently altered with the application of fatigue loading. This opens the possibility of evaluating tendon crimp as a clinical surrogate of tissue damage. The purpose of this study was to determine how fatigue loading in tendon affects crimp and mechanical properties throughout aging and between tendon types. Mouse patellar tendons (PT) and flexor digitorum longus (FDL) tendons were fatigue loaded while an integrated plane polariscope simultaneously assessed crimp properties at P150 and P570 days of age to model mature and aged tendon phenotypes (N = 10-11/group). Tendon type, fatigue loading, and aging were found to differentially affect tendon mechanical and crimp properties. FDL tendons had higher modulus and hysteresis, whereas the PT showed more laxity and toe region strain throughout aging. Crimp frequency was consistently higher in FDL compared with PT throughout fatigue loading, whereas the crimp amplitude was cycle dependent. This differential response based on tendon type and age further suggests that the FDL and the PT respond differently to fatigue loading and that this response is age-dependent. Together, our findings suggest that the mechanical and structural effects of fatigue loading are specific to tendon type and age in mice. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:36-42, 2020.

Characterizing the Wool Fiber Fineness and Crimps of Menz, Dorper and Their Crossbreed Sheep

Ethiopia possesses about 30 million of sheep population which could be taken as a source of raw material for textile industries as a wise strategy to manage their natural fibers scarcity. This work explored the possible wool fiber potentials on selected sheep breeds. Three representative breeds as indigenous (Menz), exotic (Dorper) and crossbreed (50% Dorper/50% Menz) sheep breeds were considered to characterize the wool fiber properties. Samples have been taken from four main body parts for four age categories of each sheep breeds. All samples were allowed to standard laboratory conditioning before testing, and then, properties are measured based on ASTM. The results revealed that the fibers diameter and crimp frequencies of wool fiber of the three sheep breeds in Ethiopia are significantly different from each other. The crossbreeding of the Menz sheep with Dorper provides fine wool fiber. The wool fiber properties particularly the fineness and crimps of Menz, Dorper and 50% Dorper sheep of different parts and age categories are significantly different. Hence, these wool fibers shall be classified and graded based on their breeds to use for different applications, and also it could help to explore more on wool fiber production.

THE COMPARISON OF PHYSICAL CHARACTERISTICS OF ANATOLIAN NATIVE GOAT DOWN FIBERS WITH CASHMERE

Very fine and soft down-hair fibers of native goats can have a potential as a valuable raw-material source for high quality products. Therefore, down-hair fibers were collected from native goats raised in different regions of Turkey, then their physical properties were analyzed and results were compared with cashmere fibers. Along with mean fiber diameter and its variation, single fiber length and its variation, which are the most important parameters regarding spinnability of a textile fiber, this work reports for the first time fiber scale characteristics of Anatolian native goat down-hair fibers. In this respect, scale pattern, mean scale frequency, cuticle scale height, curvature, crimp frequency were analyzed as well as fiber tenacity and breaking elongation properties. The economical potential of these down-hair fibers in Turkey were also investigated. The results show that these native goat down-hair fibers, that have been wasted mostly, have very similar properties to cashmere fibers with adequate properties for spinnability, hence they have potential for high-quality textile products as a substitute for cashmere fiber.

A comparison of transcriptomic patterns measured in the skin of Chinese fine and coarse wool sheep breeds

We characterised wool traits, and skin gene expression profiles of fine wool Super Merino (SM) and coarse wool Small Tail Han (STH) sheep. SM sheep had a significantly higher total density of wool follicles, heavier fleeces, finer fibre diameter, and increased crimp frequency, staple length and wool grease (lanolin) production. We found 435 genes were expressed at significantly different levels in the skin of the two breeds (127 genes more highly in SM and 308 genes more highly in STH sheep). Classification of the genes more highly expressed in SM sheep revealed numerous lipid metabolic genes as well as genes encoding keratins, keratin-associated proteins, and wool follicle stem cell markers. In contrast, mammalian epidermal development complex genes and other genes associated with skin cornification and muscle function were more highly expressed in STH sheep. Genes identified in this study may be further evaluated for inclusion in breeding programs, or as targets for therapeutic or genetic interventions, aimed at altering wool quality or yield. Expression of the lipid metabolic genes in the skin of sheep may be used as a novel trait with the potential to alter the content or properties of lanolin or the fleece.

Conceptual description of the llama fleece structure and the potential of classing and dehairing

For an overall description of llama fiber, its fleece structure and differences between fleece types are illustrated schematically, defined through a resumed evaluation, and determined as a compound of different fiber types. A dissection method is described and 252 samples of llama fleeces were dissected forming three fiber groups, within which fine, medium, and coarse fibers are gathered separately and, therefore, a dehairing process is simulated. Taking the group of fine fibers as a reference for the product to be obtained by dehairing, an average dehairing yield of 69% was calculated, which varies depending on the fineness of the fleece. The following fiber attributes were analyzed: fiber diameter, fiber length, crimp frequency, and crimp type. These were evaluated within fiber groups and among fleece types. The process of fleece classing regarding fineness is simulated through successively excluding coarse fleeces when evaluating the results. As a step previous to dehairing, and in order to assemble the most homogenous raw material, the necessity of fleece classing regarding fineness and type was confirmed. Fleece classing regarding fineness including only fleeces with a total mean fiber diameter lower than 28 µm and a subsequent dehairing process resulted in a mean of 21.6 µm for the group of fine fibers, with 96% of the fleeces with a mean fiber diameter of the group of fine fibers lower than 25 µm and 61% lower than 22 µm. We conclude that this segment of fine fibers reflects the potential of llama fiber as a textile raw material.

Crimp frequency of a viscoelastic fiber in a crimping process

Crimp frequency during the stuffer box crimping process is of great importance for controlling morphology of crimped fibers. A fiber is considered as a viscoelastic rheological fluid, and an approximate formulation for crimp frequency is obtained revealing the main factors affecting the crimping process.

Nonlinear vibration mechanism for fabrication of crimped nanofibers with bubble electrospinning and stuffer box crimping method

This paper aims to produce nanoscale crimped fibers using stuffer box crimping and bubble electrospinning. Nanofibers are originally obtained via a ruptured bubble and then crimped with the stuffer box crimping method. During this spinning process, the governing equations for nonlinear transverse vibration of an axially moving viscoelastic beam with finite deformation are established using the Hamiltonian principle. The crimp frequency is affected by many factors, including spinning conditions and mechanical properties of fibers. The obtained governing equations can be further used for numerical or analytical study of the crimping mechanism.

An ovine quantitative trait locus affecting fibre opacity in wool

This experiment was originally structured as a genome-wide screen for quantitative trait loci (QTL) affecting resistance or susceptibility to facial eczema disease (FE), a liver mycotoxicosis. Two Finnish Landrace (F) rams were crossed to three Texel (T) ewes to produce three cross-breed (designated F×T) rams. The F×T rams were then outcrossed to 210–230 Coopworth ewes each to generate three half-sib families, and 200 progeny per sire family were used in the FE QTL experiment. In a FE-phenotyping trial, the 600 five-month old lambs were orally challenged with a fixed dose rate of sporidesmin (FE mycotoxin) to determine their disease status. About 217 informative microsatellite markers, which were evenly spaced throughout the 26 ovine autosomes, were analysed in the FE study. Genotyping for the FE experiment was conducted in two stages: a primary and a secondary screen. In the initial primary screen, 46 most FE-resistant and 46 most FE-susceptible progeny of each sire family were selectively genotyped with the markers and analysed. Resulting chromosomes carrying suggestive and significant FE QTL were then followed up in a secondary screen when all progeny were genotyped for final analysis; there were seven chromosomes that underwent secondary screening, viz. OAR1, OAR2, OAR6, OAR13, OAR18, OAR19 and OAR20. During the FE-phenotyping trial period, mid-side wool samples were collected from the unshorn lambs for fibre measurement; the wool traits measured included yield, staple length (StapLen), crimp frequency, fibre curvature (FCurv), fibre opacity (FOpac), fibre diameter mean (FDMean) and fibre diameter standard deviation (FDsd). In a linkage analysis of wool traits, using the Haley–Knott regression method with the available “FE-generated” genotypes, a highly significant QTL for fibre opacity was detected on OAR20.

Genetic selection for wool quality.

Abstract This paper reviews the feasibility of genetic selection for wool quality. More than 30 papers were studied in the present investigation. The traits which have been considered in the majority of the literature for inclusion in the selection programmes were: (a) wool quality traits (fibre diameter, staple length, staple strength, standard deviation of fibre diameter, coefficient variation of fibre diameter, yield and crimp frequency) and (b) wool weight traits (greasy fleece weight and clean fleece weight). Before the studied traits can be proposed as the selection traits, estimates of genetic parameters as well as their relationship with other production traits are needed. Weighted mean of estimates for direct heritability ( h 2 ), maternal heritability ( m 2 ) and variance ration due to permanent maternal environment ( P 2 ) from references 1-37 were calculated to be 0.30-0.61, 0.02-0.08 and 0.03-0.16, respectively. The studied breeds were wool breeds and dual-purpose (wool and meat) breeds. In wool breeds, the weighted mean estimates of genetic correlation were ranged from -0.53 to 0.84 among wool traits and were ranged from -0.38 to 0.25 between wool traits and other traits such as live bodyweight, litter size at birth, litter size at weaning and litter weight weaned. The high estimates of h 2 indicate that the response to selection may be reliable but the unfavourable genetic (phenotypic) correlations with other traits are a concern.

Ultrafine wools: comfort and handle properties for next-to-skin knitwear and manufacturing performance

This study aimed to quantify the skin comfort and handle properties of a range of wool fabrics produced from ultrafine wool (13.7–15.1 µm) and in doing so determine if differences in fiber diameter and staple crimp frequency (5.3–7.1 crimps/cm) were important in these properties. The fabrics were evaluated using a range of subjective and objective measurement techniques, including the Wool ComfortMeter, the Wool HandleMeter and in wearer trials. This work indicated that single jersey fabrics made from ultrafine wool are approaching the limit of objective and subjective evaluation of next-to-skin comfort. The results from the Wool ComfortMeter, Wool HandleMeter and the wearer trial show that there were no significant effects that can be attributed to wool staple crimp (fiber curvature) in these ultrafine wool fabrics. The work also demonstrated a difference in the manufacturing response when knitted fabric made from wools of different fiber diameter (13.7–23.7 µm), and using yarns of the same count, resulted in a progressively higher fabric mass per unit area as mean fiber diameter was progressively reduced.

The dynamics of collagen uncrimping and lateral contraction in tendon and the effect of ionic concentration

Under tensile loading, tendon undergoes a number of unique structural changes that govern its mechanical response. For example, stretching a tendon is known to induce both the progressive “uncrimping” of wavy collagen fibrils and extensive lateral contraction mediated by fluid flow out of the tissue. However, it is not known whether these processes are interdependent. Moreover, the rate-dependence of collagen uncrimping and its contribution to tendon's viscoelastic mechanical properties are unknown. Therefore, the objective of this study was to (a) develop a methodology allowing for simultaneous measurement of crimp, stress, axial strain and lateral contraction in tendon under dynamic loading; (b) determine the interdependence of collagen uncrimping and lateral contraction by testing tendons in different swelling conditions; and (c) assess how the process of collagen uncrimping depends on loading rate. Murine flexor carpi ulnaris (FCU) tendons in varying ionic environments were dynamically stretched to a set strain level and imaged through a plane polariscope with the polarizer and analyzer at a fixed angle. Analysis of the resulting images allowed for direct measurement of the crimp frequency and indirect measurement of the tendon thickness. Our findings demonstrate that collagen uncrimping and lateral contraction can occur independently and interstitial fluid impacts tendon mechanics directly. Furthermore, tensile stress, transverse contraction and degree of collagen uncrimping were all rate-dependent, suggesting that collagen uncrimping plays a role in tendon's dynamic mechanical response. This study is the first to characterize the time-dependence of collagen uncrimping in tendon, and establishes structure–function relationships for healthy tendons that can be used to better understand and assess changes in tendon mechanics after disease or injury.

Transient treatment of pregnant Merino ewes with modulators of cortisol biosynthesis coinciding with primary wool follicle initiation alters lifetime wool growth

The economically important characteristics of the adult fleece of Merino sheep, such as increases in clean fleece weight, fibre length, fibre diameter and crimp characteristics are determined during critical phases of fetal development of the skin and its appendages. Genetics plays a major role in the development of traits, but the maternal uterine environment could also influence development. Treatment of pregnant ewes with cortisol and its analogues has previously been shown to produce changes in wool follicle morphology. The aim of this study was to determine the effect of transient manipulation of maternal cortisol status during critical phases of wool follicle initiation and development in utero. From Days 55–65 post-conception, singleton-bearing Merino ewes were treated with metyrapone (cortisol inhibitor) or betamethasone (cortisol analogue). Lambs exposed to metyrapone in utero were born with hairier birthcoats than the control or betamethasone treatment groups (P &lt; 0.05), displayed a 10% increase in staple length and a reduction in crimp frequency for the first three shearings (P &lt; 0.05). Co-expression network analysis of microarray data revealed up-regulation of members of the transforming growth factor-β and chemokine receptor superfamilies, gene families known to influence hair and skin development. These experiments demonstrate that presumptive transient manipulation of maternal cortisol status coinciding with the initiation of fetal wool follicle development results in long-term alteration in fleece characteristics, namely fibre length and fibre crimp frequency. These results indicate it is possible to alter the lifetime wool production of Merino sheep with therapeutics targeted to gene expression during key windows of development in utero.

Characterizing local collagen fiber re-alignment and crimp behavior throughout mechanical testing in a mature mouse supraspinatus tendon model

BackgroundCollagen fiber re-alignment and uncrimping are two postulated mechanisms of tendon structural response to load. Recent studies have examined structural changes in response to mechanical testing in a postnatal development mouse supraspinatus tendon model (SST), however, those changes in the mature mouse have not been characterized. The objective of this study was to characterize collagen fiber re-alignment and crimp behavior throughout mechanical testing in a mature mouse SST. Method of approachA tensile mechanical testing set-up integrated with a polarized light system was utilized for alignment and mechanical analysis. Local collagen fiber crimp frequency was quantified immediately following the designated loading protocol using a traditional tensile set up and a flash-freezing method. The effect of number of preconditioning cycles on collagen fiber re-alignment, crimp frequency and mechanical properties in midsubstance and insertion site locations were examined. ResultsDecreases in collagen fiber crimp frequency were identified at the toe-region of the mechanical test at both locations. The insertion site re-aligned throughout the entire test, while the midsubstance re-aligned during preconditioning and the test's linear-region. The insertion site demonstrated a more disorganized collagen fiber distribution, lower mechanical properties and a higher cross-sectional area compared to the midsubstance location. ConclusionsLocal collagen fiber re-alignment, crimp behavior and mechanical properties were characterized in a mature mouse SST model. The insertion site and midsubstance respond differently to mechanical load and have different mechanisms of structural response. Additionally, results support that collagen fiber crimp is a physiologic phenomenon that may explain the mechanical test toe-region.

Examining differences in local collagen fiber crimp frequency throughout mechanical testing in a developmental mouse supraspinatus tendon model.

Crimp morphology is believed to be related to tendon mechanical behavior. While crimp has been extensively studied at slack or nondescript load conditions in tendon, few studies have examined crimp at specific, quantifiable loading conditions. Additionally, the effect of the number of cycles of preconditioning on collagen fiber crimp behavior has not been examined. Further, the dependence of collagen fiber crimp behavior on location and developmental age has not been examined in the supraspinatus tendon. Local collagen fiber crimp frequency is quantified throughout tensile mechanical testing using a flash freezing method immediately following the designated loading protocol. Samples are analyzed quantitatively using custom software and semi-quantitatively using a previously established method to validate the quantitative software. Local collagen fiber crimp frequency values are compared throughout the mechanical test to determine where collagen fiber frequency changed. Additionally, the effect of the number of preconditioning cycles is examined compared to the preload and toe-region frequencies to determine if increasing the number of preconditioning cycles affects crimp behavior. Changes in crimp frequency with age and location are also examined. Decreases in collagen fiber crimp frequency were found at the toe-region at all ages. Significant differences in collagen fiber crimp frequency were found between the preload and after preconditioning points at 28 days. No changes in collagen fiber crimp frequency were found between locations or between 10 and 28 days old. Local collagen fiber crimp frequency throughout mechanical testing in a postnatal developmental mouse SST model was measured. Results confirmed that the uncrimping of collagen fibers occurs primarily in the toe-region and may contribute to the tendon's nonlinear behavior. Additionally, results identified changes in collagen fiber crimp frequency with an increasing number of preconditioning cycles at 28 days, which may have implications on the measurement of mechanical properties and identifying a proper reference configuration.

Production, properties and processing of American bison (Bison bison) wool grown in southern Australia

American bison grow a thick coat of fibres which assists them to withstand severe climatic conditions. Bison fibre was traditionally used in textiles by native North Americans. This study aimed to quantify the production, fibre attributes and dehairing processing of bison fibre produced from bison grazed in north-eastern Victoria. Three age/sex classes were sampled (n = 16) at seven body positions in spring. The fibre growing area was measured. Fibre was tested for diameter distribution, clean washing yield, proportion of fine fibres &lt;36 µm and fine fibre length, and processed by cashmere dehairing. Bison were 1–2 years of age, liveweights 160–450 kg and had mean fibre growing area of 1.4 m2. They produced an average 1184 g (range 530–1640 g) of fine fibre with mean fibre diameter 18.5 µm, clean washing yield 76.5%, wax content 9.8%, suint content 14.5%, clean fine fibre yield 56.4%, fine fibre length 37 mm and fibre curvature was 93°/mm. Mid-side fibre had a crimp frequency of 6.5/cm and mean resistance to compression of 6.6 kPa. Fibre had a tenacity of 8.7 cN/tex and an extension of 39.3%. Restricted maximum likelihood mixed model analysis showed age/sex class and sampling site significantly affected all fibre attributes. Finer and longer fibre was produced in anterior sites and in younger bison. Fibre curvature declined 5.3°/mm for each 1-µm increase in mean fibre diameter. Dehaired fibre had a mean fibre diameter of 17.8 µm and mid-length of 28 mm, suitable for woollen spinning. The production by bison of coats containing significant amounts of fibre indicates that careful harvesting of fibre could form an important source of income in bison enterprises.

Crimp frequency is strongly correlated to myofibroblast density in the human anterior cruciate ligament and its autologous tendon grafts

Collagen crimp is essential for maintaining viscoelastic properties of normal ligament and tendon tissue. The actin isoform α-smooth muscle actin (ASMA) has been identified in fibroblastic cells of these tissues. These highly differentiated cells, so-called myofibroblasts may transmit tensile forces to the extracellular matrix, thus it has been suggested that they are responsible for the wrinkling of the extracellular matrix and the formation of crimp. During anterior cruciate ligament (ACL) graft remodeling, crimp formation plays an integral role. Thus, it was our purpose to determine the relationship between myofibroblast density and crimp frequency in human tendon graft tissue and the ACL. Different tendon grafts and ACLs were harvested from young human multi-organ donors immediately after death. Myofibroblasts were immunostained with a monoclonal antibody, and histomorphometry was performed using a digital imaging system. Crimp length was measured, and data were correlated. All tendons and ACLs showed a significant correlation of myofibroblast density and crimp frequency (R(2) 0.81-0.43). The strongest correlation was found for the patellar tendon, the poorest for the gracilis tendon. There is also evidence that the phenotype respectively the shape of myofibroblasts might be responsible for different stages of crimp formation. With the present investigation, we found that myofibroblasts might be involved in crimp formation and should be viewed as an integral part of normal tendon and ligament tissue. Furthermore, the shape of myofibroblasts may further indicate the contractile potency of the extracellular matrix, thus presenting a dynamic and variable crimp rather than a static situation. This study is an experimental study. In terms of clinical relevance all the mentioned tendons can be used as auto- or allografts for ACL reconstruction, nevertheless their microscopic structure and cellular population have yet not been adequately investigated and compared.

Genetic improvement of wool production in Spanish Merino sheep: genetic parameters and simulation of selection strategies

Wool production of the Spanish Merino breed was analysed after several decades of genetic selection to improve meat production. Genetic parameters (heritability and correlations) were estimated for greasy fleece weight, staple length, crimp frequency and fibre diameter of 1869 Spanish Merino purebred sheep. Heritabilities ranged from 0.08 ± 0.050 (fibre diameter) to 0.22 ± 0.060 (staple length), and the genetic correlations ranged from –0.63 ± 0.159 (crimp frequency – staple length) to 0.75 ± 0.222 (fibre diameter – staple length). Genetic simulations were developed to show the consequences of eight selection strategies, which included single trait selection on wool traits and liveweight (the current selection criteria) and index selection combining traits. The results show that it is possible to improve wool and growth traits at the same time. Also, our results show there is indirect genetic progress for wool characteristics using the current liveweight selection criterion.