Unless you are acquiring alpacas purely for the pleasure of owning the animals, you will, in some way, be working with alpaca fibre.
In building a foundation herd, alpaca breeders must understand the basic anatomy of the fibre their animals produce, as well as the differences between Huacaya and Suri fibre.
Table Of Contents
The Structure of Alpaca Fibre
There are three structural sections present in all alpaca fibre:
- cuticle or scale
- cortical cells
- intracellular binder
Overall, the fibre is composed of a protein called keratin, but the fibre’s ”build” is based on a complex series of cells, each with a unique function.
The cuticle cells are flattened and hard. They do not fit evenly together, and have edges that protrude from the shaft of the fibre creating a serrated edge. The cuticle is responsible for the fibre’s aesthetic properties including softness and lustre.
As a basis for comparison, the cuticle cells of sheep’s wool protrude from the shaft about 0.8 micron. Alpaca cuticle cells protrude 0.4 micron and are thus softer than wool.
It is also from the cuticle that alpaca fibre gains its ability to repel water, to felt when washed, and to resist physical as well as chemical wear.
The cortical cells are rounded, elongated, and spindle shaped. Basically, they are thick in the middle and taper at the ends to form a point.
These cells are load bearing, giving the fibre its strength, and are also responsible for its superior ability to repel water.
The fibre’s intracellular binder is responsible for holding all of these structures together. Think of it as a sort of “cement.”
While all alpaca fibre has the same three main components, there are key differences between Huacaya and Suri fibre.
Huacaya and Suri Fibre
On Huacaya fibre, the cuticle cells protrude a little more than on Suri. Internally, Huacaya fiber is similar to sheep’s wool and has a bilateral structure. There are two types of cortical cells: orthocortical and paracortical.
These cells grow in bundles adjacent to one another, creating the characteristic crinkle or ”crimp” of Huacaya fibre.
Suri fibre has a lower cuticle height and lesser scale frequency, so it feels slippery to the touch and is more lustrous in its sheen.
Each fibre must be processed differently, with Suri being the more difficult to handle. It lacks cohesion, and is thus harder to spin, with more fibre being lost in the process.
Suri fibre is also heavier and bulkier since more of the straight fibre’s are needed to make yarn. A 218-yard / 199 meter ball of Suri fibre yarn costs approximately $25 / £15, whereas an equal amount of Huacaya costs is around $18 /
£11. (Please note that it is not unusual for the two fibre’s to be blended in yarn.
Follicles and Fibre’s
The fibre’s grow from both primary and secondary follicles. Primary follicles produce fiber with greater diameter and little to no crimp.
They are the remnants of outer ”guard hairs” that have been largely bred out of alpaca genetics in an effort to improve the fibre quality.
The secondary follicles produce the down or undercoat. These are the fine soft hairs that are the hallmark of luxury alpaca fiber. The higher the ratio of secondary to primary follicles, the finer, more uniform, and softer the fleece.
Secondary follicles exhibit a subtype called the derived secondary follicle, structures which have their own root and enter the follicle sheath from the side. These are the finest fibres of all and will be present in a high percentage in alpacas that are considered ”elite.”
A type of coarse fibre known as ”medulated” creates problems for producers when it is present in a fleece. Medulated fibre is not acceptable in premium markets. These hairs do not accept dye readily, and create unacceptable variations in finished yarn.
- Alpaca fibre contains no lanolin, making it hypo-allergenic with an extremely low ”prickle” factor as compared to wool.
- Alpaca’s yield 87-97% of their fleece as clean, usable fibre compared to 43-76% for sheep.
- In testing conducted by the Yocum-McCall Testing Laboratories, alpaca wool was shown to be three times as warm as sheep’s wool.
- If won in an ambient temperature of 0 F / 17 C, alpaca will return a comfort range of 50 F / 10 C.
- The approximate tensile strength of alpaca fibre is 50 N/ktex compared to the industry standard for textiles of 30 N/ktex.
Evaluating a Fleece
Judging a fleece has as much to do with sensation or ”feel,” as it does any set criteria. The best fleeces are:
- slippery (Suri)
- bright (luster for Suri)
There are, however, objective measurements that are applied, and alpaca breeders should be familiar with the terminology of this criteria.
- histogram – A histogram is a graph of the distribution of mechanical measurements by diameter and statistical frequency in a given sample of fibre.
- staple length – A number of factors influence staple length including, nutrition, environment, and genetics. The greatest staple lengths will be present in Suri fibre, which has no crimp. As an animal ages, it produces progressively shorter staple lengths, as do pregnant and lactating dames.
- micron count – By definition a micron is 1 millionth of a meter or 100th of a millimetre. As a basis of comparison, a human hair measures 60 microns, Alpaca fibre is graded by micron measurements that fall into these ranges:
- Royal: less than 20 microns
- Baby: 21-23 microns
- Standard: 24-28 microns
- Adult: 29-32 microns
- Coarse: 33-35 microns
- Very Coarse: greater than 35 microns
- standard deviation – A calculation to express the consistency of micron count across a tested sample. The lower the ”SD” number, the greater the consistency of the fibre diameter.
- co-efficient of variation – Expressed as a percentage, CV is another method for describing micron evenness in a sample, providing a more accurate comparison between samples than that which can be derived from the standard deviation alone. Fleeces with exceptional fineness have CV values of less than 20%.
- comfort factor – Fibres with a diameter of more than 30 microns will feel prickly against the skin. The comfort factor is arrived at by subtracting the percentage of fibres with a diameter greater than 30 microns from 100%.
Density, which refers to the number of follicles per area of skin, is the most important quantitative characteristic that can be applied to the evaluation of a fleece. Obviously animals with higher density produce heavier fleeces, but that fibre will also tend to be finer.
As the density of a fleece increases, the diameter of the primary fibre decreases because the secondary follicles force the primary ones to conform due to the closeness of their alignment.
In a dense fleece, you can see all the way to the animal’s skin when the fibres are parted. In fleeces with less density, the primary fibres will be 30-40 microns thick and will cross and intertwine with the secondary fibres obscuring the skin.
You can arrive at a visual estimate of how tightly the fibres are packed by parting the fleece and judging how much skin can be seen at the roots. A fleece that is extremely dense will reveal only a thin line of skin. This is a reasonably reliable method of evaluating a fleece, but there are other approaches.
Pushing the fibre down and feeling the amount of resistance is another method often used. Some people will even just grab the fleece to see how it fills the hand. Both can be misleading. Coarse fibres offer more resistance, and also more completely fill the hand.
Regrowth or Staple Length
”Regrowth” or ”staple length” are both terms referring to the actual length of the fibre. Together, length and density determine how much the complete fleece will by, which is the industry standard basis for payment.
From one alpaca to the next, the total weight of the fleece may range from 2-12 lbs. / 0.9-5.4 kg or more.
To judge the rate of regrowth, accurate records must be kept of shearing dates. As alpacas age, they will produce less fibre, a diminishing capacity seen especially in females that are reproducing.
Fineness is also important to a good-quality fleece. As shown earlier in this chapter in the definition of micron count, the lower the average fibre diameter (AFD), the finer (and thus softer) the fibre.
Many factors affect AFD including age. AFD tends to increase about 2 points per year until an alpaca has reached 4-5 years of age. Diet and hormones are also relevant influences on AFD. Males have coarser fibre in general, but the fleece of a gelded male retains its fineness due to the lower testosterone levels in these animals.
It’s important to use histogram results to learn to assess the fineness of fibre by hand since many of the subjective influences on this crucial factor can be greatly misleading.
A tightly crimped fleece, for instance, will often feel coarser than it really is according to an accurate histogram reading.
The ripples or waves in fibre are called the “crimp.” The more crimp in a fibre, the finer and denser it is generally believed to be.
This is, however, a ”rule” with many exceptions. It is true that fibre with a greater degree of crimp is easier to spin.
In judging the quality of a fleece, the uniformity of the crimp across the entire blanket is important. This is more important than the ”style” of the crimp, which is described as high or low frequency in terms of number of crimps per inch.
The tendency of fleece to separate into cylindrical groups is called ”lock structure.” This quality is much more evident in fleece from a Suri alpaca than from a Huacaya.
The denser and more uniform the fleece, the more pronounced the lock structure. There is also reference to lock style with Suri fleece, which should twice or wave.
The most desirable style is for small ringlets or waves that are highly uniform. This should start very close to the skin, and be consistent throughout the whole fleece.
Goals for Breeding Programs
Alpaca breeders use these characteristics to create breeding goals, culling from their program animals that do not meet the specified set of criteria.
Culling is not a euphemism for “killing,” it simply means selling the animals to another breeder or, in the case of beloved pets, having them spayed or neutered.
Examples of points in a set of breeding goals might include:
- Temperament qualities that relate to ease of handling and manageability.
- High fertility rates with easy births, efficient lactation, good maturation rates, and early weaning.
- Excellence of conformation in regard to bone structure and posture as well as the fleece volume and capacity.
- Specific fleece goals including fineness in microns, density, length of staple, uniformity of colour, and brightness.
In any breeding program, specific figures relative to fleece quality are still a guide only, since so many factors can influence the numbers. This does not mean, however, that the numbers should be ignored.
When you are purchasing alpacas, the farmer with whom you are dealing should be able to discuss these factors with you. Don’t deal With someone, who says that these measurements are unimportant and that the only determination of fleece quality is that made by ”hand.”
”Hand” is important, especially in the show ring, but the measured figures are the only way to arrive at an accurate and definitive basis of comparison.
As fibre animals, alpacas may be shown for their body conformation and overall excellence, but the fleece itself is also shown competitively.
The British Alpaca Society (www.bas-uk.com) on its ”Shows and Events” page states that fleece shows routinely have 200-300 entries.
Participation in fleece events adds prestige to the reputation of an alpaca farm, and award winning fleeces command higher prices when sold for textile production.
Consult the home page of your governing alpaca association to determine what kinds of events are held in your area and to learn more about the criteria for entry.