Alpaca Fiber Grades and Micron: How to Read Your Test Report

You sheared your alpacas, sent a few samples off to a lab, and a sheet of numbers and a bell curve came back. AFD, SD, CV, comfort factor, a histogram. If you are not sure which numbers matter or what to do about them, you are in good company. This guide reads a real alpaca fiber test report line by line, explains what the micron count and the alpaca fiber grades actually mean (and why no two countries agree on them), and turns the result into a clear decision for your herd. It works whether this is your first report or your five-hundredth.

The 30-Second Version#

If you read nothing else, read this:

• Micron (AFD, average fiber diameter) is the master number. It is the average thickness of the fiber. Lower is finer, softer, and worth more. Human hair is around 70 to 100 microns. A fine alpaca is under 20.
• There is no single global grade system. "Royal," "Baby," and "Superfine" are commercial trade names, not an official standard. The US (AOA) uses unnamed Grades 0 to 6. Australia classes by micron bands. Compare numbers, not labels.
• Uniformity matters as much as fineness. A low SD (standard deviation) means the fibers are all a similar thickness, which is what makes a fleece feel soft and spin well.
• 30 microns is the comfort line. Fibers over 30 microns are what you feel as "prickle." Comfort factor is the percentage of fiber 30 microns and under, and you want it near 100.
• Micron rises with age. Expect roughly a micron a year of coarsening early on, then it levels off around age four. Always compare an animal to others its own age.
• One report is a snapshot. The trend is the truth. Test the same animal, same spot, same time each year, and watch the direction.

The rest of this article explains each of these.

Micron: The One Number Everything Hangs On#

A micron is one-thousandth of a millimeter. Fiber diameter is measured in microns, and it is the first thing any buyer, processor, or judge looks at. The average fiber diameter (AFD) on your report is simply the average thickness of all the fibers in the sample.

The rule is short: lower is finer, finer is softer, and softer sells for more. For a sense of scale, a single human hair is around 70 to 100 microns. A premium alpaca fleece can be under 20. That is why micron is the number printed largest and talked about most.

But micron alone can lie to you, which is the whole reason the rest of the report exists. Two fleeces can share the same average and feel completely different in the hand because one is even and one is full of coarse stragglers. So read the average first, then keep going.

There Is No Single Grade Standard (Stop Comparing Labels)#

This trips up almost everyone. You will see fiber described as "Royal," "Baby," "Superfine," "Grade 2," and a dozen farm-invented tiers, and you will assume they map onto a single official scale. They do not.

The familiar names (Royal, Baby, Superfine) come from the Peruvian and commercial garment trade, and even there the exact cutoffs wander by a micron or two between sellers. The major associations take completely different approaches:

• United States (AOA): In 2021 the Alpaca Owners Association published a numbered system, Grades 0 to 6, and deliberately left the names off because they decided the trade terms were inconsistent worldwide.
• Australia (AAA / AWEX): Australia does not use named grades at all. It classes fleece to a wool-industry standard and prices it in micron bands. The commercial pool (AAFL) does publish named grades for selling, shown below.
• United Kingdom and continental Europe (BAS, AZVD, and national associations): No named grade table either. British, German, and Italian breeders describe fleece by raw micron and judge it as a whole, and for selling they fall back on the international trade names (Royal, Baby, Superfine) in the last column. There is no separate European grade standard.

Here is how a given micron reading lands across the systems. Read it as "the same fleece, four different labels":

The US AOA grades (approved 2021) are the only numbered standard, and the AOA deliberately left names off. The Australian commercial ceilings (AAFL) are Royal up to 19.0, Baby up to 22.5, Superfine up to 26.5, Huarizo up to 31.0, Adult up to 34.0. Those boundaries fall between the AOA steps, so a single AOA grade can straddle two Australian names (that is why some rows show two). Trade names vary by seller. Use this to translate between systems, not as a single law. Readings below 15 microns (rare and elite) and above 35 microns (coarse, and common in older or pet animals) fall outside the AOA's seven grades.

The one thing nearly everyone agrees on is the 30-micron comfort line. Above roughly 30 microns, fiber is stiff enough that you feel it as prickle against skin, so that is the practical boundary between next-to-skin clothing and everything else (rugs, felt, outerwear). Hold onto that number. It comes back when we read comfort factor.

Reading Your Test Report, Line by Line#

Here is what each line on a standard report means, in plain English, and the range breeders generally aim for. Treat the "good" column as what breeders target, not an official pass mark. Most labs define these terms but stop short of grading them.

If you only learn two lines beyond AFD, learn SD and comfort factor. SD tells you whether the fleece is even, and comfort factor tells you whether it will be pleasant against skin.

How to Read the Histogram (the Bell Curve)#

The histogram is the graph on your report, and it is just a picture of everything in the table above.

• The horizontal axis is fiber diameter in microns.
• The vertical axis is the percentage of fibers at each thickness.

The shape tells the story at a glance:

The width of the bell is the standard deviation made visible. A fat curve is literally a big SD. A real reported example of a fine, even fleece looks like this: AFD 21.4 microns, SD 4.1, CV 19.2 percent, and only 2.6 percent of fibers over 30 microns. Notice how the CV sits under 20 and the SD in the low 4s. That is a tight, sellable curve.

For Breeders: SD or CV, Which Uniformity Number Do I Trust?#

Beginners can happily skip this part. AFD, SD, and comfort factor are plenty to get started. But if you are ever choosing between two close animals, this is the one expert debate worth understanding, because it changes which animal you pick. SD is the honest measure of variation. CV can quietly fool you.

Here is the trap, using a worked example fiber analysts have flagged for years. Take two animals with the exact same SD of 4.7:

• A fine one at 22 microns has a CV of 21.4 percent (4.7 divided by 22).
• A coarser one at 27 microns has a CV of 17.4 percent (4.7 divided by 27).

If you select on "lowest CV," you just picked the coarser animal, even though both are equally uniform. CV's real job is comparing uniformity between animals of different fineness. When you are judging how even a single fleece is, trust the SD.

Why Your Numbers Change Year to Year#

Before you make any decision, understand what moves these numbers, because some causes are fixable and some are not. The short version: genetics and steady nutrition are the levers you control, and age is the one you cannot. The detail is below.

Age (not fixable). This is the big one. Fiber coarsens as an alpaca ages, fast in the first couple of years (roughly a micron a year) and then largely leveling off around age four. A study published in 2024 found the jump from under-one-year animals to older ones was around six microns, with little further change after the early years. So your cria's first fleece is the finest she will ever grow. Select young animals knowing the micron will rise a few points, and always compare an animal to others its own age.

Genetics (your biggest lever). Fineness is moderately heritable. In plain terms, roughly a third of the difference in fineness between animals is genetic and passed to their offspring (studies put the figure around 0.25 to 0.40). That is high enough that choosing finer, more uniform sires and dams measurably pulls your whole herd's micron down over a few generations. This is exactly what fiber EPDs and breeding values are built on, and it ties straight into your pedigree and breeding records.

One catch worth knowing: the finest animals often grow the lightest fleeces, because fineness and fleece weight pull against each other genetically. Chase micron alone and you can slowly shrink your fleece weight per shearing. The way breeders get both is to select for density (more fibers packed into the same area), so weigh every fleece as well as testing it, and judge an animal on fineness, uniformity, and weight together.

Nutrition (fixable, affects evenness and can nudge micron). Feeding does not turn a coarse alpaca fine, but it controls uniformity. A sudden diet change, a heavy worm load, illness, or the stress of birthing leaves a thin, weak band in the staple, a "tender break," and the fleece snaps there when it is processed. Keep nutrition steady year-round, stay on top of parasites, and do not let pregnant or nursing females drop condition. Overfeeding does not buy you fineness and can nudge micron up.

Sex and breed (compare like with like). Males commonly test a couple of microns coarser than females and carry more guard hair, though this varies between herds. Suri runs about two microns coarser than Huacaya of the same age. None of this is a fault. Judge breeding stock against same-sex, same-age, same-breed peers. If you are still choosing between the two coats, our guide on the best alpaca breed for beginners covers the Huacaya and Suri trade-offs.

Season (minor). Fiber grows a little faster and coarser in summer and finer in winter. It is a small ripple compared to age, and consistent annual shearing manages it for you. (See when to shear alpacas for timing.)

What To Actually Do With the Result#

Numbers are only useful if they drive a decision. Here is a simple framework that scales from one pet to a commercial herd.

• Fine and uniform (low AFD, low SD, high comfort factor). Keep for breeding and consider showing. This is the animal that improves your herd and commands the price. A clean, low-micron record is a real selling point that feeds straight into what a well-bred animal is worth.
• Average micron but very uniform. A solid producer. Good fleece for yarn, and worth breeding to a finer mate to pull the next generation down.
• Coarse but young. Wait. Retest at two and at three before judging. Early coarseness can be partly age, and the trend matters more than the first number.
• Coarse with a high SD or a fat right tail. This animal is dragging your clip's average up. It is a better fit as a fiber pet, a guard animal, or for rug-grade and felting fiber than as breeding stock.
• A sudden bad year on a previously good animal. Suspect nutrition, parasites, or a stress event before you blame genetics. Check body condition and feeding, fix what you find, and retest next year.

One caution before you over-react to a small change: labs are precise to about a third of a micron, so a half-micron wobble between years is noise, not a trend. Look for movement of a micron or more, sustained across years.

How AlpacaKeep Helps#

A single report is easy to file and forget. The value is in the trend, and the trend is exactly what a clipboard or a messy spreadsheet loses.

AlpacaKeep stores every fiber result against the individual animal, so you can see an animal's micron, SD, and comfort factor move year over year, catch a coarsening trend early, and compare each animal to the rest of your herd at the same age. When it is time to plan matings, the fineness and uniformity history sits right next to the pedigree, so you are breeding on data instead of memory.

We are building this for exactly the small and growing farms that cannot justify a full classing setup but still want to breed seriously for fleece. Join the AlpacaKeep early-access list to track your herd's fiber history as we roll the platform out.

Start Reading Your Fleece Like a Breeder#

You do not need to memorize every term. Read the AFD for fineness, the SD for evenness, and the comfort factor for how it will feel against skin. Translate the grade label back into the micron number so you are comparing apples to apples across countries. Then watch the trend, compare each animal to its own age group, and let the numbers, not the marketing, tell you which animals to breed.

Sources#

• Alpaca Owners Association (AOA), U.S. Alpaca Fiber Standard (Grades 0 to 6, approved 2021), alpacainfo.com
• Australian Alpaca Association, "Understanding fleece results" and fleece classing (AWEX), alpaca.asn.au
• Australian Alpaca Fleece Ltd (AAFL), commercial fleece grades, aafl.com.au
• Art of Fibre and AAFT (Australian Alpaca Fibre Testing), guides to reading a fiber test, artoffibre.com and aaft.com.au
• Paul Vallely (AAFT), "Should breeders use SD or CV?" (the SD versus CV worked example)
• Kuźnicka et al., Archives Animal Breeding, 2024 (age effect on fiber diameter and the plateau around age four)
• Comparing fiber quality and staple length in Suri and Huacaya alpacas, Frontiers in Animal Science, 2023 (breed and sex differences, comfort factor)
• Penn State Extension, "Nutritional Effects on Alpaca Fiber," updated 2025 (nutrition, tender breaks, fleece weight)