• Internal Parasites

    The Department of Agriculture, NSW, has kindly granted permission for an article on Worms in Alpacas (dated 12th June 2003, PDF, 35KB) to be posted on this website. The author is Anne Oakenful, Technical Officer from the Diagnostic Parasitology Department of the Elizabeth Macarthur Agricultural Institute, NSW Department of Agriculture. Download here.

  • Husbandry for the NSW Southern Tablelands

    If you are a newcomer to the industry and/or are interested in further information, we have prepared a document (vet-approved) on our alpaca husbandry practices and general care routine as appropriate for the Goulburn NSW and Southern Tablelands regions. Please to obtain a copy (PDF).


The following information comes from the very informative ‘Info Pak’ book written by Riverina Fleece Testing Services (RFTS) of Albury-Wodonga, and is reproduced with their permission. As we have not had fleece tested for some years, having sold our stock, the following contact details may be out of date, but are included as a courtesy to them. Pleae let us know of any current details so that we may update this page.

John and Val Park
Ph: 02 6026 0551
PO Box 1062, Lavington NSW 2641 or PO Box 1462, Wodonga VIC 3689


Fleece Sampling Site

  • be consistent from alpaca to alpaca
  • sample size for micron testing: 20g
  • sample size for micron and yield testing: 30g
  • a representative sample gives a representative result
  • a Fleece Grid Sample should be taken from ten random sites – fleece spread out on the classing table
  • sample identification should not be written on plastic bags with texta, but should be written clearly on labels (placed inside the bags)

Optical Fibre Diameter Analyser (OFDA)

Fleece testing accuracy improves with increasing fibre count. For example, the difference between a 1% coarse fibre and a 2% coarse fibre with 1000 fibres is only 20 fibres. This is why the RFTS tests 4000 fibres per sample. OFDA has no equal: it is simply the most accurate.
The Optical Fibre Diameter Analyser (OFDA):

  • is the very latest in Australian fibre testing technology
  • is IWTO Full Test Method 47 Approved
  • measures from 4 to 300µm
  • measures fibre curvature from 0 to 360 degrees per millimetre (deg/mm)
  • scans the whole of the sample
  • measures up to 12,000 fibres per minute
  • is installed in 22 countries around the world
  • measures wool, cashmere, mohair, alpaca
  • measures medullated or hollow fibres

Lab Procedures

Scouring:

  • Chemical: ideal for classing flocks of sheep
  • Detergent: ideal for the processing chain and ram sales

Minicoring:
After overnight conditioning, the whole clean sample is cored by multiple kneedles passing through and withdrawing 2mm snippets of fibres.

Testing:
Fibres are randomly spread on a glass slide and placed on the stage of the OFDA. ALL test results are processed with 4000 fibre counts for complete accuracy of MFD, SD, CVD and %>30µm. Test data is imported into RFTS files and then all test reports are issued.

Principles:

  • protective rubber gloves are worn at all times to avoid contamination
  • cleanliness and constant removal of wool fibres by vacuum are paramount
  • minicore cylinder, needles, spreader, OFDA and slides are vacuumed after each sample
  • clean slides are deposited in sealed containers when not in use
  • only clean scoured wools enter the Laboratory

Temperatures:

  • Scouring: 65°C
  • Drying: 105°C
  • Laboratory: 21°C and 65% relative humidity

Pointers to Ponder

  • is it better to be a piece of history or part of historical change?
  • class and test sires prior to joining
  • class and test dams prior to joining
  • high CVDs - attributable perhaps to:
    • high variability along and between fibres
    • stretchy/tender fleeces
    • two staple types
    • very young alpacas
  • aim to provide a level plane of nutrition between shearing, whatever it may be
  • A + B = C may well be the most important equation
  • you have to have accuracy of tests to build in the quality required. Perhaps some “short term pain for a long term gain’
  • never forget the second opinion: always purchase subject to an OFDA test

Fleece Sampling Terminology

Micron (µ) or Micrometre (µm)
One µm equals one-millionth of a metre (m), or one-thousandth of a millimetre (mm). A human hair is approximately 75-100µm in width.
NOTE: micron and micrometre are the same unit. ‘Micron’ is the old name, and has been superseded by the name ‘micrometre’, as defined by the International System of Units (Système International (SI) d’Unités)
Mean Micron
The average µm of a sample. The sum of individual fibre widths (in µm) divided by the total number of fibres. For example, 5 fibres of width 18µm, 19µm, 20µm, 20µm and 21µm have an average, or mean diameter of [18µm+19µm+20µm+20µm+21µm]/5 = 19.6µm
MFD Micron
Actual Mean Fibre Diameter - made up of along and between fibre measurements
MFD Var
The variation of Mean Fibre Diameter from the overall average of all samples tested
SD
Standard Deviation is a measure in µm either side of the MFD in which 68% of fibres lie and is +/-. For example, a fleece of average 20µm with a SD of 5 is written 20±5µm and means 68% of fibres lie within the range 15µm–25µm
CVD%
Coefficient of Variation of Diameter. Also known as Covariance or CV. Expressed as a percentage of Standard Deviation and Mean Fibre Diameter.
CV = SD/MDF×100/1
CF
Comfort Factor. An indication of how many fibres are less than 30µm.
0% of fibres above 30µm = 100% CF
3% of fibres above 30µm = 97% CF
%>30
The percentage of fibres greater than 30µm. The opposite of Comfort Factor
SF
A decisive figure for processors. Spinning Fineness is a calculation of MFD and CV into a single measure of fineness expressed in µm.
NOTE: a CV of 24% has a zero effect on Spinning Fineness.
SF = 0.881MFD√[1+5(CV/100)2]
Curve
The Mean Fibre Curvature measured in degrees per millimetre (deg/mm) of fibre length. The LOWER the angle, the LOWER the Staple Crimp Frequency.
Curve SD
Measurement of the spread of curvature. The higher the standard deviation (SD) the greater the distribution of curvature. The lower the SD the more uniform the fibres are. Research is on-going.
FEM©
Fine Edge Micron© is the number of µm lower than the mean where the finest 5% of fibres begin
CEM
Coarse Edge Micron is the number of µm greater than the mean where the broadest 5% of fibres begin

NOTE: Generally, the lower each of the SD, CVD, SF, CURVE[SD], FEM and CEM values are, the better the fleece within each micron category.

What is Spinning Fineness (SF)?

The value of spinning fineness (SF) is derived from the Martindale theory on the effective fineness of wool.
SF = 0.881MFD√[1+5(CV%/100)2]
where MFD = Mean Fibre Diameter
CV = Coefficient of Variation

This formula means that a reduction in CV of 5% has the same effect on spinning fineness as a 1µm reduction in MFD. For example:
21.0µm and CV of 28% = SF of 21.8µm
21.0µm and CV of 18% = SF of 19.9µm
21.0µm and CV of 24% = SF of 21.0µm

A CV of 24% has a zero effect on Spinning Fineness.


What is Crimp?

  • crimp is the term given to the natural wave that occurs in wool fibres
  • when fibres are aligned within a staple or lock the staple crimp frequency or quality is highly visible
  • in a wool staple or lock the fibres are aligned to show the crimp wave pattern. This crimp pattern can be measured to give the staple crimp frequency and assessed to determine the character or boldness of the crimp
  • the crimp in the wool fibre is related to the bilateral structure of orthocortex and paracortex within the wool fibre. The orthocortex has been observed to be always present on the outside of the crimp curve
  • wool fibres with a diameter less than 25µm have a clear bilateral segmentation
  • fibres with diameters between 25µm and 35µm have less clear bilateral arrangements, and over 35µm other arrangements can be seen
  • the extent to which orthocortex and paracortex are present in any wool fibre determines the chemical and physical properties of the wool fibre
  • wools of low crimp frequency tend to have increased proportions of orthocortex, while more highly crimped fibres have more paracortex

Measuring Staple Crimp

  • staple crimp frequency is equal to the number of crimps (crests or troughs of the waves) per centimetre (cm) of staple length (or the number of waves per inch)
  • crimp frequency is similar to the traditional Quality Numbers or Bradford Counts used to describe wool, that were originally based on the number of crimps per inch
  • staple crimp frequency correlates with the OFDA measurement of Mean Fibre Curvature
  • staple crimp frequency in fine wool flocks is very poorly correlated to mean fibre diameter. Therefore the quality number or crimp frequency of wool is not a good indicator of fibre-fineness
  • staple crimp frequency can be easily assessed with a ruler or with other simple devices that can match the crimp pattern. With a ruler, simply place a staple alongside one edge and count the number of crimps over 2 to 4cm of the staple. Divide the number of crimps by the length (ie 2 to 4cm) to give a figure of crimps per cm
  • an automated measurement of staple crimp frequency on wool bale grab samples is being developed by CSIRO Division of Wool Technology for use prior to staple length and staple strength testing. This device is also being developed to measure other wool style attributes such as crimp definition, dust penetration, greasy wool colour and brightness

What is Fibre Curvature?

  • mean fibre curvature is the average curvature of fibre snippets measured by the OFDA
  • the value is expressed in degrees per millimetre (deg/mm) fibre length
  • the correlation between staple crimp frequency and fibre curvature is high
  • therefore low staple crimp frequency wools have low fibre curvature, while high staple crimp frequency wools have a high fibre curvature
  • fibre curvature can be measured throughout processing, in the raw wool, top, roving, yarn and even the fabric, whereas it is impossible to measure staple crimp frequency past the greasy wool stage. This makes fibre curvature a potentially more useful measurement than crimp frequency
  • curvature could be used as a specification for wool throughout the processing pipeline from farm to fabric. Diameter is the only other measurement which can also be used from farm to fabric
  • the variation in curvature or standard deviation of curvature has been related to crimp definition or the degree of character or boldness in the staple crimp pattern
  • at a certain level of curvature a high standard deviation would indicate a staple with poor character, while a low standard deviation would indicate a staple with good character

Measuring Fibre Curvature

Measuring fibre curvature

  • the diagram shows how the curvature of a fibre snippet is measured. The angle A represents the amount the fibre turns in degrees from point B to point C. The OFDA measures a 200µm section of the fibre snippet and multiplies this value by 5 to convert the degrees per 200µm to degrees per millimetre (deg/mm). All measured snippets are averaged to give the mean fibre curvature. The standard deviation or variation in fibre curvature is also calculated
  • The OFDA is able to measure fibre curvature at the same time as it measures the mean fibre diameter and variation in fibre diameter. Therefore curvature can be easily measured on samples sent to your OFDA fleece testing laboratory for fibre diameter testing

Fibre Curvature Data on the OFDA Histogram

The fibre curvature data measured by the OFDA is presented at the top of the histogram. The following example is used in describing the data:
Curve=74.6[57]deg/mm
This is the mean fibre curvature and standard deviation of curvature in brackets.

Curve Number=2647
This is the number of fibre snippets measured for curvature. This is less than the sample size set for measuring fibre diameter due to the fact that some fibres in the sample overlap in the OFDA slide and hence cannot be measured for fibre curvature.