Ramsay Farms

Quality breeding stock and companion animals

I've created this helpful page to answer questions for those that have never micron tested your sheep and are curious about it, or those who have micron tested their sheep and now want to know what to do with those numbers that are staring at them in the face :) :D

I believe here that micron testing lambs in their first fall, and then all sheep yearly in the spring, before shearing, helps with our ultimate goal of fine fleeces. We do not ignore structure, genetic ability, or personality at the gain of finer fleeces, but we look at the overall package. I also believe that by microning all animals every year, I am able to track the health of the sheep through the fleece testing along the fiber (Texas A&M please see link below). I've seen both  dramatic and gradual improvements in different lines of my Shetlands and Bluefaced Leicesters and consider this opportunity a priceless tool to help me decide how to improve my flock further.

Please take the time to read the below information. I'm happy to discuss fleece at any time!

A link on the OFDA 2000 procedure that Texas A&M uses:
http://www.iwgofda.com/ofda2000.htm

A wonderful 'starter' powerpoint presentation in regards to wool:
http://www.avs.uidaho.edu/avs476/IntroWoolNX.ppt (requires Microsoft PowerPoint program)


Key Terms


Mid Side Sample : A sample of wool (a small hand full) taken from the mid point on the side of  sheep usually at the time of shearing.

Histogram : A method of graphing the distribution of individual fibres in a fleece sample. When comparing histograms, visual impressions may be distorted if the scale frequency differs.

Micron : 1 micron = 1 millionth of a metre.

Mean Fiber Diameter : In a fiber test, a sample of wool is laser scanned to find the mean or average fibre diameter of the measured sample. The fleece is more valuable if the average fiber diameter measured in microns is lower.

Standard Deviation : A measure of how much the fiber diameter varies within the tested sample. This is also measured in micron.

Coefficient of Variation : Calculated by dividing the standard deviation by the average fibre diameter and then multiplying by 100. It measures the range of fibre diameter variation relative to the average fibre diameter.

Coarse Edge Micron : Indicates the number of microns greater than the average in the area of the coarsest 5% of fibres tested. Better quality and more uniform fiber distribution is indicated by a lower percentage of coarse edge fiber.

Comfort Factor : The percentage of fibres less than 30 micron.

Crimp : The waviness of a fiber. It can be measured and expressed as the number of complete waves per unit length. Although not always a reliable indicator, finer fiber often has more crimps per unit length.

Staple : A well defined pencil like bundle of fibres that are aligned.

Density : A reference to how much wool sheep is carrying and a term that is often used in the show ring. Although there are many indicators of density, they can be misleading due to variations in micron. Skin follicle testing and weighing shorn fleece are reliable methods of determining sheep's fleece density.

taken from http://www.genstock.com.au/Fleece_Testing_Reporting_Functions.htm

Fleece Testing Reporting Functions

FIBRE DIAMETER DISTRIBUTION

is an integral part of the Merino Wool Industry and affects all participants from the commercial grower to the end user who wears the finished garment. Its affect ranges from management problems such as fleece rot and fly strike, through sale price due to dust penetration, tip weathering and doggy wool, to prickle in the finished garment.

Selection for heavier wool cuts tend to increase fibre diameter variation.

FIBRE DIAMETER DISTRIBUTION

is directly related to:-

Staple structure and Style (arrangement of fibres within the staple).
Fleece tip (dust and water penetration, tip weathering, top/noil ratio).
Fleece rot.
Fly strike.
Micron control.

FIBRE DIAMETER DISTRIBUTION

is the distribution, or number, of fibres of each diameter in any given wool sample. When measured, it enables the degree of fibre diameter variation, or uniformity, to be assessed.

Good staple structure requires fibre diameter uniformity. Evenly sized fibres grow and crimp in unison to give an even, distinct crimping pattern. This gives wool true style and character.

Poor staple structure has considerable fibre diameter variation. Unevenly sized fibres produce crimps of uneven length and depth which give rise to a disrupted crimping pattern and feathery tip.

Resistance to fleece rot and fly strike is very dependent on good staple structure which naturally facilitates the rapid draining and evaporating of moisture which may enter the staple.

A blocky tip does not necessarily indicate evenly sized fibres!! It is often formed after shearing when copious wax cements the tips of the wool fibres together which creates the blocky surface and disguises any naturally feathery tip.

Feathery tips allow substantial dust penetration. They also weather and tend to break and become noil during processing.

Handle is very dependent on fibre diameter distribution.

Poor Handle is largely attributable to fibre diameter variation (these wool’s deteriorate in appearance and become stronger microning).

 

FIBRE DIAMETER DISTRIBUTION HISTOGRAM

The Histograms and measurements are provided as a guide to assessing the comparative wool quality and average micron of this group of sheep.

SD INFO
1. Standard Deviation - indicates the micron "spread" or distribution of the majority of the fibres.

CV INFO
2. C of V - is the coefficient of variation which indicates the micron "spread" relative to the average micron. It allows the "spread" of micron of sheep of different average micron to be compared. Uniformity of fibre diameter is the basis of wool quality and is characterised by well defined and evenly spaced crimps (better known and "style").

C of V can also be used as an efficient indicator of staple strength. Low C of V of fibre diameter, lead to a high staple strength.

COARSE EDGE INFO
3. Coarse Edge - indicates the proportion of comparatively coarse fibres which are not described by the standard deviation or coefficient of variation.

It measures the "tail" of the FD Histogram. These fibres disrupt the internal staple structure and are the framework for feathery tips. In severe cases, they can be pre-emptive of the future increase in the average micron of that sheep.

The coarse edge qualifies and fine - tunes the C of V assessment.

%FIBRES >30 INFO
4. % Fibres > 30 micron - Indicates the proportion of fibres which are greater than 30 micron. When there are more than 5 % of fibres > 30 micron, prickliness becomes apparent thus indicates the degree of prickliness that a finished product is likely to have.

% FIBRES <15 INFO
5. % Fibres < 15 micron - Indicates the proportion of fibres which are less than 15 micron. This is helpful in determining those animals with a left hand shift on their histograms.

SPINNING FINENESS INFO
6. Spinning Fineness - is a numeric calculation that relates C of V to the actual micron in terms of spinning ability.

The spinning qualities of wool are enhanced by a low coefficient of variation, which enables the wool to be processed at standards less than the given micron.

For e.g. a 20 micron wool with an 18% C of V, has the spinning qualities ( or fineness) of a 19 micron wool. The same 20 micron wool with a 29% C of V, would have a spinning quality (or fineness) of 21 micron.

YIELD INFO
7. Yield measures the "true wool" by eliminating the grease, swint, wax and dirt.

FIBRE CURVATURE INFO
8. Fibre Curvature - is a new approach to measuring "crimp" in wool, and recent evidence shows that curvature is probably the third most important fibre specification after diameter and length.

What use is curvature?

Curvature relates strongly to staple crimp characteristics, particularly crimp frequency - for as frequency increases, the fibres are increasingly curved. But curvature is not the same as character (staple crimp definition), which is a measure of how well aligned fibres are. Fibre alignment and thus staple crimp definition does however relate to the CV of curvature, since it is physically hard to align fibres differing in curvature. Figure 1 illustrates these points:

Recent scientific evidence confirms that wool fibre curvature influences processing efficiency, particularly during topmaking and spinning operations, yarn thickness and evenness and fabric thickness, handle and quality.

Topmaking:
Wools of high crimp curvature tend to show increased fibre breakage during carding, relative to wools of low crimp curvature. Wools of poor crimp definition (high CV of curvature) tend to show increased fibre breakage in processing, in comparison to wools of good character.

Spinning:
As fibre curvature increases, yarns become progressively more uneven, thicker, and show a progressively increasing frequency of faults. Fabric: As fibre curvature increases, fabrics become increasingly thick and rigid.

Handle:
As fibre curvature increases (at a constant diameter), wool becomes increasingly hard to compress, displays increasing bulkiness, develops an increasingly noticeable texture, a dry feel, and generally feels increasingly harsh. By comparison, cashmere (renowned for its silky softness) represents the combination of low average fibre diameter and low average fibre curvature.

Measurements of fibre curvature have the potential to have a major positive impact on the ability of our wool to deliver to consumers the soft, lightweight and easy care fabrics consumers increasingly demand.

Interpreting Results

In raw wool, OFDA measurements of curvature commonly range from 60 o/mm, for wools of low crimp frequency, up to around 130 o/mm, for superfine samples. The standard deviation of curvature on the OFDA commonly ranges from around 40 - 100 o/mm, generally increasing as the average curvature increases, and as staple crimp definition decreases.

Measurements of fibre curvature could therefore be a useful means of identifying and specifying wools of particular style, such as Superfine wools, or the target wool type of the Soft Rolling Skin Sheep selection system. The latter is characterised by a low average curvature relative to the average diameter, as well as low CV’s of both diameter and curvature.

IMPORTANT

Higher rainfall areas benefit from lower figures.
Lower rainfall areas will handle both low and higher figures.
Tall histogram profiles with a narrow base indicates better quality wool’s.
Squat profiles with a broad base indicate lesser quality wool’s.

REMEMBER do not neglect the basic need for wool production - select for productive wool cutters and frame, then fine - tune the wool to suit your own environment.

 Highly curved, aligned (eg. good character 90's quality)
 Low curvature, well aligned (eg. good character 56's)
 Variable curvature, poor alignment (eg. doggy wool)

A simple tool for assessing fibre diameter / fibre curvature combinations on adult wool (greater than 2 years old) is shown in the graph below. This roughly defines the combinations for "true-to-type" and potential Elite or SRSä wools.

 
Fibre Curvature (deg/mm)
50-59Fibre Diameter (um)
14.5 to 15.4
15.5 to 16.4
16.5 to 17.4
17.5 to 18.4
18.5 to 19.4
19.5 to 20.4
20.5 to 21.4
21.5 to 22.4
22.5 to 24.4
140+
True To
Type
True To
Type
 
 
 
 
 
 
 
130-139
 
True To
Type
True To
Type
 
 
 
 
 
 
120-129
Possible ELITE
 
True To
Type
True To
Type
 
 
 
 
 
110-119
Possible ELITE
Possible ELITE
 
True To
Type
True To
Type
 
 
 
 
100-109
Possible ELITE
Possible ELITE
Possible ELITE
 
True To
Type
True To
Type
 
 
 
90-99
 
Possible ELITE
Possible ELITE
Possible ELITE
 
True To
Type
True To
Type
 
 
80-89
 
 
Possible ELITE
Possible ELITE
Possible ELITE
 
True To
Type
True To
Type
 
70-79
 
 
 
Possible ELITE
Possible ELITE
Possible ELITE
 
True To
Type
True To
Type
60-69
 
 
 
 
Possible ELITE
Possible ELITE
Possible ELITE
 
True To
Type
50-59
 
 
 
 
 
Possible ELITE
Possible ELITE
Possible ELITE
 

Understanding and Interpreting Micron Testing by Angus McColl



Understanding and Interpreting Micron Testing

by Angus McColl

The integrity of sampling - the careful and proper selection of a sample - is the most critical factor involved in measurement of diameter and other fiber measurement in individual animals. The samples must be taken at the middle of the side in the blanket location. (See Figure 3.12 in the ARI screening manual, published in this issue.) The sample should be uniformly cut as close as possible to the skin level, which is the base of the staple, and should be no smaller than 2 square inches in size. The sample should be kept in the staple configuration, which is its natural growth state. It should not be brushed out, cleaned up, or folded. Flat-bladed shears (such as round-tipped Fiskars scissors) or clippers are recommended as the safest tools to use in taking samples.

Length of Fiber Sample

Maintaining the staple formation of the sample submitted to the laboratory is important for a practical reason: The 2-millimeter sample used for measurement in the Laserscan is cut close to the base of the staple to measure fiber that has grown side by side under the same environmental conditions. These conditions include level of nutrition, pregnancy, lactation, and stress caused by sickness or trauma. The coat of a recently shorn animal generally has not been exposed to highly variable environmental conditions, so environmental influences on varability of fiber diameter will have been minimized. Working with staple lengths shorter than 1 1/2 inches is problematic because the staple configuration breaks down and we are unable to take an even cut across the base during sample preparation.

Packaging and Identifying Individual Samples

Once the 2-inch-square sample is taken, it should be placed in a plastic sandwich-size bag and clearly labeled with the following identification:

Identification numbers (ear tag, microchip, and/ or registration) Age (date of birth is preferable to age in years) Sex (male, female, gelding) Phenotype (huacaya or sun) Date of sampling

Major Factors Influencing Fiber Diameter

Three factors have primary impact on fiber diameter: age, sex, and level of nutrition. As an animal matures, its fiber tends to have a higher or coarser micron value. Males frequently possess a higher micron value than females. The level of nutrition affects fiber diameter results because overfed animals produce higher micron values than those on a maintenance diet. This does not mean that animals should be underfed to produce finer fiber. An unsound or unhealthy animal is a poor risk in a breeding program regardless of its fiber diameter Underfeeding causes significant negative side effects, such as lowered fertility, lower birth weights, and higher cria mortality rates. The safer course is to maintain alpacas on a thrifty but nutritious diet that maintains a healthy body condition to produce fiber that lives up to its genetic potential, by following the animal husbandry practices suitable for your farm's location and the advice of a veterinarian familiar with camelids.

Genetics and selection are also fundamental to producing sound animals with fine fiber The alpaca samples included in our Laserscan database since June 1994 indicate that a broad genetic base exists in the U.S. alpaca population. A diverse genetic base creates opportunities for selection of desirable traits, including fiber fineness. But a word of caution is in order: In animal selection, focusing on one particular trait increases the risk of negative traits that may be linked to the one being selected. For example, focusing for fiber fineness may inadvertently select animals with small body size and low fleece weights.

Understanding Laserscan Micron Test Results

Samples tested by Laserscan yield a micron test report, examples of which are shown in Figures 1 and

  1. At the top of the report is administrative information provided by the identification submitted with the

individual sample. The histogram displayed on the report depicts the measurement of 2,000 fibers in scale. The histogram is the most common graphical presentation of quantitative data; in the micron test report, the variable of interest, fiber diameter in microns, is placed on the horizontal axis, and the relative frequency values (percentage of fibers observed within a micron measurement) are shown on the vertical axis.

Depending on the height of the results, the histogram is printed on either a 12% or 24% scale to fit our letter-size report format. The bottom line (horizontal scale) is measured in 1-micron increments (one micron is equivalent to one thousandth of a millimeter or one twenty-five thousandth of an inch).

To analyze the micron test report histogram, find the average fiber diameter (AFD), "Fiber Diameter in Microns," on the horizontal scale. Standard deviation (SD) is a term representing an average of individual deviations (plus or minus micron values) from the mean, the average fiber diameter The smaller the standard deviation, the more uniform the population of fibers measured will be.

Standard deviation is the most stable of variability measurements and is used in the computation of other fiber statistics, such as the coefficient of variation (CV). This value, used in the statistical analysis of different populations of fiber (different animals), is the standard deviation divided by the average fiber diameter multiplied by 100 and reported as a percentage.

The uniformity of two alpacas' fleeces with different average fiber diameters is illustrated by the following results (see Figures 1 and 2):

Statistic Test #1 Test #2
AFD 22.7 23.9
SD 5.0 5.0
CV 22.0 20.9

The animal with the more uniform fleece is shown in Test #2: It has the lower CV but a higher AFD. The percentage of fiber greater than 30 microns is also included in the report. In commercial application and breed selection, this data is of interest because it shows the coarse edge that determines the final use of the fiber It has a relationship to the strength of the yam processed from the raw fiber and influences "prickle" factor, the scratchy quality associated with coarser fibers.

Both the date of birth and the date the sample was taken must accompany the report to identify the age of the animal. A test report not including the sample date is not as helpful as one confirming that the test results represent fiber taken when the animal was a specific age.

Equipment to Measure Fiber Diameter

Yocom-McColl Testing Laboratories is equipped with the latest instrumentation technology for measuring average diameter of animal fibers: Sirolan Laserscan, developed by CSIRO, and Optical Fibre Diameter Analyser, developed by BSC Electronics. Both companies are located in Australia. These instruments are calibrated using tops from Interwoollabs, the only recognized supplier of calibration tops to the worldwide textile industry. A diagnostic and calibration check is performed each day on both instruments. The accuracy of measurement is +0.3 micron, and the tests are performed under standard conditions of 65% +2% relative humidity (RH) and a temperature of 70 ± 2º F.

A Marketing and Genetic Selection Tool

When utilized properly, objective fiber testing can be a powerful marketing and genetic selection tool. Objective measurement is an assessment made without the influence of personal feelings or prejudice. Visual appraisal and fiber handling are fundamental aspects of fiber judging but very weak appraisal methods of accurately identifying fiber diameter Instrumentation can accomplish the measurement of fibers within a micron. Because the measurements are so tiny, the difference between a sample at 20.5 microns and one at 22.5 microns is small mathematically but critical in commercial use and pricing structure.

Based on this factor alone, fiber-testing technology gives breeders a useful tool to analyze fiber and track the progress of their selection programs. The determination of average fiber diameter helps identify the best end use for fiber and is information that mills require before making their purchasing decisions. The ability to provide information on fiber quality places alpaca producers in a stronger position to receive what their fiber is worth. Very few people buy and sell commodities without knowing everything they can about them. Information is power in the marketing world, and objective fiber assessment provides it. But from the perspective of the fiber-testing facility, the micron test is only as good as the sample and the information submitted for testing. The laboratory cannot jeopardize its integrity by providing results from improperly taken samples, either by location or size. Breeders have the same interest in maintaining their reputations with high-quality animals and by keeping accurate records of their overall performance.

Figure 1. Micron Test Report, Test #1
Figure 1. Micron Test Report, Test #1

Figure 2. Micron Test Report, Test #2
Figure 2. Micron Test Report, Test #2

About the Author

Angus McColl is a member of the American Society for Testing and Materials (ASTM) D13 Textile Committee and a member of hte Industry Fiber Group. He is the U.S. representative at the annual technical meeting of the International Wool Testing Organization (ISTO) in Nice, France. Yocom-McColl Testing Laboratories, Inc., has been involved in fiber testing since 1963. The laboratory is an independently owned, commercial wool and animal fiber testing facility located at 540 West Elk Place, Denver, CO 80216-1823.