Disclaimer: This post represents my currently amassed knowledge up to this point. It is by no means meant to be comprehensive, and since it is filtered through my brain, without citing reference material, I make no promises as to accuracy. Some of it may even be more opinionated than factual. You have been warned!
I first started out in alpacas just over a year ago now. Before we bought our first two pet girls, about all I knew about alpaca fiber was that it feels nicer to me than sheep's wool. I think that I am probably not alone in starting out with such an impoverished knowledge base before jumping in feet first.
I don't like being in the dark, so I set out to learn as quickly as possible. I am still quite far from knowing it all, and I sure still haven't a clue how to spin, knit, or weave, but I know one heck of a lot more than I did a year ago. Here is what I have learned.
It seems that one of the first things new alpaca owners learn to evaluate is crimp, because it is a fairly easy thing to appreciate. I consider myself lucky in that regard, because I didn't even learn a thing about crimp until I was well on my way to building a herd. The very first thing I learned was that alpaca, unlike wool sheep, often grow a second coat of guard hair amongst the wooly fibers, particularly as they age. Think of a double-coated dog -- that layer of straight, bristly hair that sticks out and guards the insulating wool coat from the elements. Many alpacas will grow this guard hair coat as well, and this will cause profound itchiness if not removed before processing the fiber into a finished garment. Take-home message: Guard hair is bad. It is easy to spot, because it sticks out from the back of an animal. That also makes it fairly easy to avoid. Wherever possible, I have made every effort to avoid it.
The term "guard hair" or even just "hair" has such a negative connotation in the alpaca world -- despite being extremely common in alpacas -- that some people will refer to it using the term, "Strong, straight primaries." This is technically accurate, but I think it is also somewhat sugarcoating the issue.
"Primaries" is a term that confused me for awhile, and it is still pretty confusing, but I am starting to get a better handle on it. Primary follicles are different from secondary follicles. In many alpacas, the primary follicles grow guard hair, which is much thicker, coarser and itchier than the softer wool that grows from secondaries. However, it is possible to select for alpacas whose primary follicles produce a fiber that is nearly equivalent in diameter to the secondaries, and in even more advanced alpacas, the primaries may have wave or even crimp. Selecting for more secondaries and fewer primaries is another major goal of alpaca breeders. Breeders also try to select for primaries and secondaries that are equal in diameter. The practical end goal of all of this is to make all of the fibers as uniform as possible in diameter, length, and shape, because the more uniform the fiber, the less itchy the end product.
That brings me to the next thing I learned about: Histograms. The histogram is what most people call the fiber analysis, even though the histogram is technically only the graph of the analysis. What most people care about is the statistics. The four most common statistics are: AFD, SD, CV and CF or %>30, depending on which testing lab you use.
What the heck, right? They sound like obscure sports stats or something.
AFD stands for Average Fiber Diameter, and it is measured in microns (that's a millionth of a meter). This is the number that most breeders jump up and down and crow about, and I'll admit that I do it, too, but I do not believe that it is the most important. It is literally what it sounds like: the average diameter of the fiber in the sample you have submitted. Most people are shooting for as low a number as possible. Vicuna have AFDs of around 12 - 14 microns, and many of today's alpacas are in that range as well. Although many breeders get excited about breeding finer and finer fleeces, those fleeces with stronger (higher) micron counts are also valuable. In fact, a fleece with a micron count of 20-22 is arguably much more versatile than one which is ultrafine. AFD may some day be one of the things that defines different breeds of Huacaya alpaca.
SD stands for Standard Deviation. This is a statistical term that boils down to a measure of fleece uniformity. 4 is a pretty average SD. So, if you have an alpaca with an AFD of 20, and an SD of four, that means that two-thirds of its fibers fall between 16-24 microns.
SD is one number where lower is pretty much undeniably better. Even if your AFD is super low (say, 14.8), if your SD is high (say, 5.2), there is going to be a good amount of variation in that fleece that will make it feel less soft than the AFD would suggest. On the flip side, even a fleece with a fairly strong micron can feel softer than you would expect if the SD is very low. As far as I can tell, there are no disadvantages to having as low an SD as you can manage, and in my opinion, SD is more important than AFD. (The ancient Royal Incan alpacas have been documented to have SDs of 1. That is totally unheard of today!)
CV stands for Coefficient of Variation. This one is confusing. It is the SD, multiplied by 100 and divided by the AFD, expressed as a percentage. Basically, this is done because higher micron fleeces also tend to have higher SDs. It enables a fairer comparison of a higher AFD fleece to a really fine one. As with SD, lower is better, across the board, although, again, because of how it is calculated, the ultrafine fleeces will have higher CVs and that doesn't mean that they suck, by any means. I have found it most useful for comparing higher micron fleeces.
The last, and the number that I feel is most important (at least in low-micron fleeces) is CF or %>30. These are two different measurements of essentially the same thing, but inverted. That sounds complex, but it is actually really basic and easier to understand than SD or CV. CF stands for Comfort Factor. It measures the percent of fibers that are below 30 microns. Fibers at or above 30 microns often equate to guard hair, especially when the rest of the fleece is very fine. The ideal for this number is 100%, and this is one where higher is always better.
The inverse of CF is % > 30; that is, the percentage of fibers above 30 microns. Here, again, lower is better, with zero as an ideal. I can't recall ever having seen a report that proclaimed zero percent over 30 microns, though I have seen plenty of reports with 100% Comfort Factor. This is due to differences in the testing laboratories, which is one of the major limitations of fiber testing.
Now, the percent of fibers over 30 microns is obviously going to increase significantly as the AFD approaches 30, and thus, for those animals, this variable becomes a lot less meaningful. For an alpaca with an AFD of 28, a 30 micron fiber is still only 2 microns above the mean. For an alpaca with an AFD of 20, however, a 30 micron fiber is 10 microns above the mean, and is going to equate to a serious itch factor. A 30 micron fiber on a 20 micron AFD animal is probably a guard hair, and that is maximum itch, right there. Thus, for most alpacas, we want as few fibers over 30 microns – as high a “comfort factor” - as we can get.
I ended up putting a lot of emphasis on statistics in the beginning, as I think a lot of newbies probably do when they're first learning, because numbers are easy to understand. One of the most important things to realize, though, is how incredibly limited the fiber analysis really is. For one thing, it is typically only analyzing one small section of the blanket. It is only analyzing that year's blanket, which can be affected by environmental factors such as diet and weather conditions. Lastly, it is not even 100% accurate in the first place. The machines have a margin of error that many people don't even consider. Also, there are different testing laboratories, and those laboratories tend to give slightly different results.
Last, but certainly not least, there is an awful lot that the analysis doesn't tell you.
Most of all of the analysis measures factors that equate to the hand of the fleece. Hand, or handle, refers to how the fleece feels. AFD, SD and %>30 all contribute to hand, but so do other factors. One of these is brightness. Brightness refers to how shiny the fleece appears, and it is a function of the height of the microscopic scales that line the outside of the fiber shaft. Lower, flatter scales reflect light better and make the fleece appear brighter. They also make the fleece feel slicker, and therefore softer. Having a lot of sebaceous glands to nourish the fleece will also make it brighter and slicker and give it a softer, more appealing hand. Brightness is an inherited trait, and one well worth breeding for, but it isn't measured in the typical fiber analysis.
There are other important fleece characteristics that aren't measured on a fiber analysis. These were some of the later things that I learned about (as I said, I did my learning backwards relative to many breeders).
Crimp is a really obvious one, but it was one of the last things I explored, so it's the last piece of this essay. We all know how "curly" sheep's wool is. That's crimp, in a nutshell. Crimp comes in many different styles. These mainly relate to the frequency and amplitude. Remember that stuff from physics class? Frequency refers to how many little crimps there are on the fiber shaft. Amplitude refers to how deep those crimps are. Alpaca folks also talk about the level of "organization" to the fleece. That refers to the tendency of a fleece to form discrete bundles, and to neatly line up all of the individual fiber shafts.
Some breeders have gone into great depth to characterize the different crimp styles of alpaca fleeces, a lot more depth than I want to go into here. If you're interested, Snowmass Alpacas has done a series on this topic which can be found here. The main take-home message is that all crimp styles are useful and valuable. Crimp style, like AFD, may someday help to define different Huacaya alpaca breeds, as it does in sheep.
This brings us, at last, to that ill-defined word: "Elite." Although all crimp styles and micron counts are useful, many breeders are aiming for a very organized, high-frequency, high-amplitude fleece with a low (<17 micron) AFD, as low an SD as possible, no fibers >30 microns, excellent brightness and good staple. All of these traits together are sometimes said to make up an "elite fleece." The problem is that there are no strict objective cutoffs to delineate the difference between an "elite fleece" and one that is just really darn good, so the term becomes a pretty subjective one. It is also mired in politics and advertising, with many of the "big name" farms claiming to breed and sell only the finest "elite" seedstock, when in reality, the quality of their stock overlaps that of a small breeder who has been quietly selecting for excellence, but would not deign to use the coveted word.
So, there you have it. To sum it up: many alpacas are (still) hairy, which is pretty bad; some are not, which is good; a few are really fine and really organized, which is better, although not the end-all; and, if you get fine and organized enough, you get to call your alpacas “elite,” because everybody else does. Oh, and never mind density, because nobody really knows how to measure that objectively, anyway, even though it directly relates to the yield of your end-product.
… And that's just fleece. Never mind conformation, structure, type, and definitely never mind color. That's a whole 'nother 'blog post.
K writes this stuff, for some reason that has yet to become apparent.