PBA Fiber Study

First a little history. Last summer the PBA board voted to spend $750 to fund a fiber study by Yocom-McColl laboratory. The goal of the study was to help Pygora breeders understand their fiber and thus breed for better goats. It was also to help Pygoras compete in the very competitive international fiber market with factual information about Pygora fiber using the terms of the international fiber community. Lastly, but very importantly, it was hoped to establish objective criteria for grading Pygora fiber that could be used during the registration process.

What happened. Fiber was sent in from 14 different PBA member’s farms. It was collected from 57 different goats. Of those 57 goats, 13 did not fit the study because of age or because they were F1 animals. The samples were sent in June of 2003 and the reports sent out November of 2003. [...]

The reports that came back had so much information that I asked for help evaluating them. I wanted to see what the reports said to the individual breeder as well as figure out what the reports meant for the Pygora breed as a whole. I asked Lisa Roskopf, a former PBA registrar, PBA sanctioned judge, and major Pygora breeder, and Lisa Zietz, a PBA sanctioned judge as well as a cashmere expert to act as a fiber committee. We have had two meetings so far and have one more that will happen in May.

So, that is where we are. This report will try and help everyone understand individual fiber reports from Yocom-McColl, so you can get the most out of them. The next report, coming in the next newsletter, will speak about what we found out about our breed as a whole.

Just for comparison: (terms will be explained below.)

Micron counts and fiber. Cashmere is below 19 microns, mohair is between 23 and 31. Above 31 microns is considered course for fine fiber markets.

A typical kid mohair report shows a mean fiber diameter of around 26 microns with a standard deviation of around 7. Fibers greater than 30 microns are around 25%.

A typical cashmere report shows a mean fiber diameter of around 16.5 microns with a standard deviation of about 3 microns and no fiber greater than 30 microns.

Individual reports: Each fiber tested was given a written report and 2 or 3 histograms, (white animals got the 3rd test for medulated fibers. This test could not be done on colored fiber.) The written report tells you in a nutshell what the lab thought of the sample. Having a single peak of fine fiber is the goal. If the report states there is a lot of guard hair it means there is a decreased yield. This is one of the things that breeders can work to improve by careful choice of breeding stock. (Note, It was found that all Pygoras have some guard hair, even those listed as type “A”.)

Now look at the report of fibers less than 30 microns. ( a sample report is provided at the bottom of this page for those who have not seen one.) The line on the bottom is fiber diameter, how fat the fiber is. The line on the side is what percent of fibers fit into that size.

Under the laboratory data section it lists:

Mean Fiber diameter. This is the average diameter of the sample, the smaller the number the better.

The Standard Deviation is how spread out the curve is, how consistent was the sample. The more different types of fiber the greater the standard deviation number, the less desirable the fiber.

Coefficient of Variation. This is a statistical measurement used to again point to consistency. The less consistent the fiber is the wider the bell curve will be and the greater the coefficient of variation.

Comfort Factor is a measurement used to show how soft the fiber is. It is calculated by subtracting the percentage of fibers over 30 microns, (the ones that are stiff and poke), from 100. The higher the comfort factor the softer the fiber.

“Prickle factor”, is not used in this report but is used by some experts. It gives you the same information as comfort factor but looks at it from the opposite direction. It measures the percentage of fibers greater than 30 microns. The higher the prickle factor the more pokey, or stiff fibers there are in the sample.

Curvature of the fiber is related to crimp. The more curvature, the more crimp. Usually the more crimp, the finer the fiber. So a high number is a good thing. It means more crimp. The standard deviation of curvature is again a measurement of consistence, the more consistent the lower the number.

Those who did the fiber study will have a report for fiber greater than 30 microns. It gives the same information as the report described above but for fiber over 30 microns. It is basically for fiber that will has a high “prickle factor” or low comfort factor. This fiber is mostly guard hair. This report is not as important as the one for fiber less than 30 micron report.

Those who sent in samples of fiber for the study that was white or very light will have a medulated fiber report. Medulated fibers are guard hairs or, if their center is greater than 60%, kemp fibers. (This report is a bit hard to read as it has the histogram of the fibers less than 30 microns, the lighter grey as well as the medulated fibers, the darker grey. ) What the report tells us is some of the same information.

Mean fiber diameter: you would expect the mean fiber diameter to be less for type “A” goats, their guard hair should be silky and have little separation. It should be very high for type “C” goats where fiber and guard hair should have a lot of separation.

Coefficient of variation should be high for a type “B” Pygora as this type of fiber should have two different types of guard hairs.

Objectionable fibers are the very course fibers that you can see with the naked eye. They look chalky and do not take dye.

Flat fibers are fibers with so large a center they collapse like a drinking straw. The more there are the more kempy is the coat.

Medium medulated fibers are those with less than 60% modulation.

Have I driven you crazy yet? Don’t worry, just take a minute and look over your report. The most important things is the mean fiber diameter and standard deviation and comfort factor.

[...]Next issue will be the second report on the fiber study. It will let you know what was discovered about Pygora fiber as a breed and may help us define which animals to breed and where the Pygora will go in the future. This is exciting stuff for anyone who is serious about producing a consistent supply of fiber for the fiber markets. In the mean time, keep sending in those fiber samples to Yocum-McColl. The more animals we have in a database the better our conclusions will be.

Crimp: How kinky the fiber is. Waves per lock.

F1: First generation cross between two recognized breeds. The progeny of that cross, if it breeds true (that is reproduce a copy of themselves), can be considered a new breed.

Kemp: This is a negative term used to describe super heavy guard hair with modulation greater than 60%. It may be straight, brittle, hairy and stiff, or kinky. Kempy fibers vary depending on the breed of animal. A fleece with more guard hair than fine fiber is also sometimes called kempy.

Histogram: A report that is displayed in a bar graph that depicts the frequency of specific traits in relation to the whole.

Medulated vs non-medulated fibers: Guard hair is medulated, it has a space in the middle similar to the marrow space in some bones. Medulated fibers are coarser than non-medulated ones and tend to be stiffer and resistant to absorbing water.

Separation: The difference between guard hairs and fiber.

Yield: The amount of usable fiber from a sample of fleece.

On to part 2...