Fibre Evaluation

Fibre statistics can often be quoted by alpaca breeders selling their animals, fibre or stud services. So it is important to understand what these mean.
Fleece testing is an objective measurement of various fleece characteristics that will allow comparison between different animals.
Fleece samples are taken from the saddle about mid-side of the alpaca and send to a wool testing bureau. What you get back is called a Histogram with the main data about the fleece.
Histogram: A graphical representation of the frequency of fibre diameters in the sample. The peak shows the Mean Fibre Diameter and the Standard Deviation is shown in the spread of the bottom of the graph. 

Here are some of the common terms used to describe the fleece.
Example: MC-18,1  CV-24,9  SD-4,5  CF>30-2,1 

Mean Fibre Diameter (MFD or MC): Commonly referred to as “micron”, is the overall average fibre diameter. Measured in micron (µm). A micron is one millionth of a metre.
The lower the microns the finer the fleece. Alpaca fibre can range from as low as 13 microns to well over 30 microns.
Here the rating for Huacaya fibre (Suri differs) but it can vary from country to country:
20 microns and under, the highest quality available - ROYAL ALPACA
20 - 23 microns - BABY ALPACA or "Premium Alpaca"
24 - 28 microns - Standard Alpaca Fleece
29 - 33 microns - Coarse Alpaca
33 - 35 microns - Coarse-also referred to as "inferior"
over 35 microns - Very Coarse
Please note that these figures do not tell you about the feel or "handle" of a particular alpaca fleece. Which means that an alpaca with 25 microns can feel softer than an alpaca with 20 microns. Reasons  being genetics, feeding, keeping and the enviroment.

Coefficient of Variation (CV): The Coefficient of Variation is the SD expressed as a percentage of the MFD. The SD is multiplied by 100 and divided by the MFD. The lower this figure the better.

Standard Deviation (SD): The standard deviation measures (in micron µm) how wide the spread is, of individual fibre diameters, around the mean (MFD). 66% of fibres fall within this range. The lower the SD the more uniform and desirable the fleece is.

Comfort Factor (CF):
The comfort factor is the percentage of fibres under 30 micron or as in the USA the reports show the percentage of fibres over 30 micron (>30).
The higher the percentage of fibres over 30 micron the more ´prickly or itchy´the final product might be. For garments worn on the skin the amount of fibre over 30 micron should be as low as possible.

Curvature:
Fibre curvature (in Huacayas) is related to the crimp frequency of the fibre. It is measured in degrees per millimetre (Dg/mm) and is the amount of bend or curve over 1mm length

Address of Wool Testing Bureau S A P.O.
Box 1867
Port Elizabeth,
6001
Telephone: +27 (0)41 503 6600