Measurement

  • Comparison of Fiber and Cuticular Attributes of Alpaca and Llama Fleeces

    Forty alpaca kids, comprising 20 huacaya and 20 suri, and 20 llama “chaku” (or woolly type), were chosen for a comparative investigation of the fiber and cuticular attributes based on fiber diameter, number of cuticular scales per 100 µm of fiber length, and scale height. Out of the three parameters investigated, the number of cuticular scales proved to be a valid diagnostic trait in distinguishing suri fleece from both huacaya and llama fleeces. A further characterization of the suri fleece was obtained by considering the frequency distribution of both fiber diameter and number of cuticular scale classes. The suri fleece was clearly different from both the huacaya and llama in that it possessed the highest percentage of fibers with less than eight scales, the lowest percentage of fibers with more than nine scales, along with the lowest percentage of fibers with a diameter of more than 35 µm. The validity of these classification criteria was fully supported by a classification discriminant analysis based on the jointed investigation of the data related to scale and diameter frequency classes, whose output was a 100% correct classification of the suri specimens along with an 85.7% and 71.4% of cases correctly classified in huacaya and llama, respectively. more »
  • Fibre Measurement

    The accurate and objective measurement of various characteristics of natural fibre is known as “fibre metrology”. Measurements are useful in describing the fleece characteristics of any one animal, and can be used to compare the fibre characteristics of animals within the same herd, animals in different herds, or of the same animal at different times. They can be used to compare the progeny of one sire with the progeny of another to assist in formulating breeding strategies. They are used when fleece is sold by description, and processors may use them to predict the performance of pooled fibre during processing. Care needs to be exercised, however, in making these comparisons, as there are many non-genetic factors which may influence these measurements. Before comparing the characteristics of two fleeces, one needs to take into account the influence of such factors as the sex, age, nutrition, colour, and general health of the alpacas from which the fleeces were taken, the climate in which the fleeces were grown, and whether or not a female was lactating, or a male working as a stud sire. Other considerations should include the length of the fibre sampled, the site from which the fibre was sampled, and the technique used to measure the fibre. more »
  • Fibre Metrology of Wool and its Applicability to Alpaca

    The measurements made on wool and the reasons for those measurements are examined. It is suggested that, if the alpaca fibre-processing industry is to move beyond being a cottage industry, it will have to adopt modern total quality management. It will also have to respond to customer demands for end-products at competitive prices and processor demands for repeatable quality. This will mean price will be determined by measured fibre properties and the key properties will almost certainly be diameter and whiteness (freedom from coloured fibre). more »
  • Fibre Stats: Does The Machine Really Matter?

    For those seeking a short answer: no. There is no significant difference in the results of measurements for micron or CV made on midside fleece samples between different types of machines. But the answer can be made longer. Curvature, when measured using the same samples, showed significant variations between optical and laser methodology. And optical methods of measurement proved less reliable when trying to assess whole fleeces using grid samples, due largely to the limitations of sampling. To better understand the discussion, one must first understand the different methods used for measuring fibre, and their application in different types of testing machines. more »
  • Fibre Testing and Histograms

    The only way to know what quality fleece your alpacas are producing is to have it professionally tested. There are several wool testing services available (this is sheep country after all!). There seems to be quite a range of charges too! Whichever service you choose, you should be supplied with a “histogram” for each individual alpaca sampled as well as a summary sheet listing all your results. A good testing service will also help you to understand your histogram if you require it. more »
  • Fibre Testing. How To Interpret Your Results?

    From the sample supplied to the testing laboratory, 2000 fibres are measured and then processed to obtain, mean (average) fibre diameter, standard deviation, co-efficient of variation, histograms comfort factor, coarse edge measurement, curve, curve standard deviation, and spinning fineness. more »
  • Fleece Scoring

    The Alpaca Association of New Zealand has reviewed its fleece scoring system and decided to award 105 points instead of 100 so as to change the weighting for certain traits. This came about following a judges' training session. more »
  • Measuring Fabric Handle to Define Luxury: An Overview of Handle Specification in Next-to-Skin Knitted Fabrics from Merino Wool

    An examination is presented of the relevance of luxury to the wool textile and garment supply chain. This examination leads to a review of the concept and importance of fabric handle as a means of defining important aspects of fabric quality. Examples are given for woven fabrics of the general relationships between subjectively assessed fabric handle attributes such as fabric softness and smoothness and measured low stress, generally high deformation, fabric properties such as fabric bending rigidity and extensibility. A brief overview is presented of the development of a system for predicting a set of subjectively assessed handle attributes for next-to-skin knitted fabrics from measurable fabric properties. Seven handle attributes selected by experienced assessors as being important for defining tactile sensations associated with next-to-skin knitted fabrics were: fabric smoothness, hairiness, softness, tightness, dryness, warmth and weight. Subjective assessments on a 1–10 scale of these seven attributes, plus an assessment of overall handle, were conducted by 12 experienced assessors on 74 next-to-skin knitted fabrics. The precision of the mean assessment of the 12 assessors ranged between 0.8 and 1.1, indicating that there was sufficient consensus on key fabric handle assessments to justify development of a method for predicting them from measurements of the physical properties of fabrics. All fabrics were tested using the PhabrOmeter fabric evaluation system, which records the force exerted during insertion of a fabric into and through an orifice. Geometric parameters were derived to describe the PhabrOmeter force-displacement curve results, and statistical models were developed to predict the average handle assessments of the 12 assessors. The precision of the models in predicting the handle intensities of eight fabric attributes on an independent validation set of 22 fabrics was significantly better than the precision of an individual assessor (confidence limits = 1.4–2.6 and 2.5–3.8, for predicted and assessed ratings, respectively). A case is made that this technology has the potential to assist in the growth of new markets for Merino wool products. more »
  • Measuring Fibre Curvature: Key Issues

    The capability of instruments such as SIROLAN-LASERSCAN (LASERSCAN) and OFDA100 to provide measurements of fibre curvature has resulted in increased interest, within Australia among wool producers and exporters, and among overseas top-makers and spinners.  However, the metrology of fibre curvature measurement by these instruments is poorly understood.  Standardized conditions for preparation, and measurement procedures that stabilize the curvature of the wool fibres prior to measurement by either instrument, are yet to be defined. more »
  • Measuring and Managing Wool Quality

    Processors and wearers still often judge the comfort of lightweight wool knitwear by squeezing the fabric to gauge how ‘soft’ it is, believing a softer feel or ‘handle’ will provide an excellent wearing experience and not prickle or irritate the skin. However, Sheep CRC research has shown this relationship to be unreliable. Reliance on this relationship means that uncomfortable wool knitwear is being produced and sold, which continues to reinforce the notion that wool is a prickly fibre. New objective testing devices for comfort and handle provide the opportunity to ensure all wool garments are fit for purpose and positively reinforce the exceptional comfort properties of wool. more »
  • Reading Fibre Test Results

    Fibre testing can be like an ambush for the unwary. There is much misinformation as to what fibre test results mean and how they should be applied. The following is a short guide to help dispel some of these fibre testing myths. more »
  • Should Alpaca Breeders Use ‘SD’ or ‘CV’ When Evaluating Fibre Traits?

    Over the years I have operated AAFT, the question of whether to use Standard Deviation (SD) or Co-efficient of variation (CV) when evaluating fibre traits is undoubtedly one of the most commonly asked questions. It also happens to be one of the issues most plagued by misunderstanding, and consequently, carries the potential to de-rail breeding strategies, particularly those aimed at reducing the incidence of coarse fibres, increasing the level of fibre uniformity, improving the processing performance of fleeces or simply improving the style and handle of fleeces. more »
  • Study into Comparative Differences of Scientific Testing Machines used in Alpaca Fibre Measurement

    Objective measurement of alpaca fibre is now an integral process in the showing, breeding, marketing and classing of alpacas and alpaca fibre. Four systems are in common use, those being the OFDA and Laser systems in their laboratory and shed configurations. This study aims to test the comparability of those techniques in measuring alpaca fibre, and thereby validate their use in comparing fibre measured by different techniques. more »
  • Testing the Testers – Fiber Testing Alpacas

    In order to breed alpacas with better fleeces, we need to know the quality of the fleeces of our dams and sires. The only quantitative, repeatable, transferrable way to get this information is to submit samples for analysis in one of the many alpaca-fiber-testing laboratories. We are reliant on those results in assessing our animals, yet we rarely ask critical questions about those labs: how consistent and reliable are their test results? What instrument do they use for the test? What information do they provide? Where is the best value for money? more »
  • The Case of the Missing Coarse Fibres: Explaining the ‘Trim High’ Setting on OFDA2000 Fibre Testing Equipment

    When I first became involved with fibre testing alpacas over 15 years ago, about the only figure on alpaca fibre test reports that received any interest was the average fibre diameter (microns). Thankfully, SD is now co-starring alongside micron, as breeders appreciate the need to reduce fibre variability when breeding towards quality fleeces. Most alpaca fibre testing these days is carried out using OFDA2000 fibre testing equipment. OFDA2000 equipment measures the full length of the fibre sample. It can measure fibre samples after the samples are ‘scoured’ or cleaned of lanolin, seeds, grass etc, or it can be used to test raw fibre samples using capabilities to offset the presence of impurities on the fibres. more »
  • The Effect of Nutrition on Fibre Growth in the Alpaca

    Twelve adult male alpacas were given either 0·67 (low) or 2·0 (high) × assumed maintenance requirements for a period of 6 weeks after which time each was transferred to the alternative level of nutrition for a further 6 weeks. Fibre samples were taken from two 10-cm2 areas on the mid-side position of each animal at 2, 6, 8 and 12 weeks, and measurements of fibre weight, yield (clean fibre weight/raw fibre weight), fibre diameter and fibre length made on the samples collected at weeks 6 and 12. The higher level of feeding resulted in higher clean fibre weight (low = 0·42 (s.e. 0·03); high = 0·53 (s.e. 0·04)mg/cm2 per day, P < 0·001) and fibre growth rate (low = 186 (s.e. 10); high = 223 (s.e. 14) yon/day, P < 0·05). Changes in yield (low = 0·917 (s.e. 0·006); high = 0·929 (s.e. 0·009)) and mean fibre diameter (low = 31·4 (s.e. 1·9); high = 32·1 (s.e. 1.6) \xm) were not statistically significant. Calculations showed that the increased weight of fibre attributed to the higher level of nutrition could be explained in terms of the observed increases in fibre-length and diameter but that, unlike the sheep in which the ratio fibre length: diameter remains relatively constant under varying nutritional regimes, the effect of nutrition in the alpaca has a proportionally larger effect on fibre length than on fibre diameter. more »
  • Using ‘Fibre Growth Profiles’ to Monitor Fibre Follicle Development in Alpacas

    While many alpaca breeders have incorporated objective fibre measurement into their herd management strategies, ‘Fibre Growth Profiles’ are becoming popular for monitoring pre and post natal nutrition, particularly during the critical period of secondary follicle development in unborn crias. ‘Fibre Growth Profiles’ are linear graphs depicting variation in diameter along the fibres. This allows alpaca breeders to track nutritional intake of both the pregnant female and the cria in order to manage the development of secondary follicles, and thereby maximise potential for fibre density, fleece weight and fibre diameter. more »
  • Variable Fleece Scores

    BAS judge Liz Barlow examines why fleece scores may differ from one show to another. more »
  • Variation in Fibre Diameter Profile Characteristics Between Wool Staples in Merino Sheep

    Two experiments were conducted to examine the variation in fibre diameter profile (FDP) characteristics between staples. The mean values of all the FDP characteristics were not significantly (P > 0.05) different between staples prepared using the same and different staple preparation techniques. The residual correlation coefficient’s between staples prepared using the same staple preparation technique for all FDP characteristics ranged from r = 0.60 to 0.96. The correlation coefficients between staples prepared using different staple preparation techniques ranged from r = 0.37 to 0.97. These results indicate that it may not be sufficient to segment a single staple for estimation of certain FDP characteristics to examine differences between individual animals. One staple is sufficient to estimate the average FDP of a group of animals. FDPs generated using different staple preparation techniques can be accurately compared for most FDP characteristics. more »
  • Variation in and Sampling of Alpaca Fleeces

    Evaluating the attributes of alpaca fleeces subjectively by eye is difficult and unreliable as alpaca fleeces show large variations in attributes. In addition, our eyes (and brain) are limited in their ability to discern fibre diameter, the average of other attributes and the extent of naturally occurring contaminants. Alpaca fleeces are also affected by environmental conditions, in particular humidity, but also by storage conditions. These same limitations apply equally to wool, mohair and cashmere. more »
  • Weighing Fleeces

    All alpaca breeders need to be able to weigh their fleeces. Fleece weights are one of just a few parameters that are vital to the record of any alpaca breeding program. They are as basic and as important as the more commonly promoted results of fibre testing, such as mean fibre diameter because, however you look at it, the financial returns on sale of fleece will primarily be determined by fibre diameter and fleece weights. more »

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