Fleece Evaluation

Fineness or fiber diameter is measured in microns. One micron equals 1/25,000 of an inch or 1/1000 of a millimeter. Fineness is valued because it impacts the spinning limit. The finer each individual fiber is, the greater the number of fibers there are in a cross section of the spinning. This leads to a more uniform yarn diameter, greater yarn strength, and greater softness of handle. USDA's Denver Wool Laboratory developed the Micron System which separates wool into 16 grades based on fiber diameter. Alpaca ranges between 15 and 45 microns, with 25 microns or less being desirable. For fiber above 22 microns, prices rapidly decline about 7% for each micron increase up to 27.5 microns. Above 27.5 microns the price declines more drastically. It is reasonable to assume that the same would be expected of llama.

There are several sampling techniques which can be employed to assess fiber fineness. The Single Site Method uses a 2 inch square of fiber snipped at the skin from the mid-side area. This is the most typical sampling method breeders use for micron testing. The Three Site Method uses a 2 inch square of fiber snipped at the skin about 3 inches below the topline at the shoulder, the mid-blanket and the rump. The Grid Sampling Method is done with a shorn fleece. A grid is placed over the entire fleece and small samples are taken from each section or opening.

To gain a perspective about the fineness of llama fiber, it is helpful to compare the diameters (expressed in microns) of a variety of fibers.

Presented below are four different fiber micron classification systems. These systems can be used as a guide to determine where a specific fleece would fit based on its micron count. Comparing the four systems, it is evident that there is little consistency in the naming of the fiber categories or in the fineness associated with similar categories. It is important to note that the term "llama" does not necessarily refer to fiber originating from an actual llama.

Total fleece weight is the weight of the entire raw fleece. A more detailed method of obtaining fleece weight is to separate the fleece into three sections of the prime blanket, the apron and neck, and the legs, belly and tags and then weigh each section individually. It is desirable to have a high total fleece weight along with a high prime blanket weight since this section of the fleece commands a higher price. Clean fleece weight is the weight of the fleece after scouring or washing and dehairing. Fleece weight varies between animals and herds, and it is affected by genetics. Alpacas produce total fleece weights of 1 - 8 pounds per year and 1-3 pounds per year of prime blanket when adequately fed a good quality diet year round. It is reasonable to expect this from a fiber producing llama.

Sections of the Fleece

Staple length is the length of the sheared locks. It is the same as the regrowth or the fiber regeneration factor in subsequent shearings. Fleece regeneration can vary from 2 to 6.2 inches per year, with an average of 5 inches per year expected from alpacas. Adequate yearly fleece regeneration is economically advantageous because the fleece can be harvested yearly. It is not unreasonable to expect this regrowth rate from a fiber producing llama.

Density is the number of hair follicles per square inch of skin. It can be defined by the amount of skin showing when the fleece is parted, and by the SP ratio. The SP ratio is the ratio of secondary to primary fibers. A primary follicle produces guard hair and is surrounded by many secondary follicles which produce down. A high ratio is desirable and this determines the density of the fleece. A fine fibered sheep has a ratio of 40 or 50 to 1. Alpaca ratios vary widely from animal to animal, this is probably similar for llamas. Density can be felt by placing the hands on the surface of the blanket area and lifting. The sensation of weight correlates with density. When grabbing a handful of fleece on either side of the blanket, the amount of fleece that fills the hand is density. Fineness and density are usually mutually exclusive characteristics, and density and staple length are the primary factors contributing to fleece weight and yield.

Yield is the amount of usable fiber after processing, and it is usually calculated after washing, drying, and removal of guard hairs. Yields between 75% and 90% are normal. In South America, yields of 85% are expected and common for huacaya alpaca and 90% for suri alpaca.

Tensile strength is the amount of tension the fiber can withstand before it stretches and breaks. This can be crudely tested by holding a lock simultaneously at the base and at the tip and pulling. If the lock pulls apart with simple human strength, it is tender and will not withstand processing without breaking into shorter pieces. Alpaca fiber has more tensile strength than mohair. No testing has been done on llama, but it is reasonable to expect that it would be similar.

Microscopic View of Fiber

Scale frequency and scale height can only be determined by microscopic examination. The scales are composed of the outer cells or cuticle cells. They are on the outside of each individual fiber and do not fit together evenly causing their edges stick up and out from the fiber shaft. Their frequency is measured along the length of the fiber and their height is measured in relation to how far they stick up above the basic diameter of the fiber. The scale height of alpaca is .04 microns compared to .08 microns for wool. The scale frequency of mohair is 6 - 8 per 100 micron length of fiber and of alpaca is > 9 per 100 micron length of fiber. No research is available for the llama.

Crimp is the organized or uniform waviness or curliness of a lock of fiber. It pertains to fibers in an intact lock and is measured in waves per unit of length. The prime blanket or saddle area has the best crimp, followed by the lower body, and then the apron. More crimp does not equal finer fleece.

Crinkle is the waviness or form of each individual fiber when it is separated from a lock. The waviness is irregular, is measured in waviness per unit of length and is responsible for elasticity. Squeeze a fleece gently and the amount of springiness felt is the result of crinkle. High crimp usually equals high crinkle.

The style of a fleece is defined in the following categories. The more crimp and crinkle present, the greater the style of the fleece. Generally, as the micron count gets larger, the style classification gets worse.

1. Good wool-like crimp & good crinkle
2. Good wool-like crimp & average crinkle
3. Crimp which is not well defined & good crinkle
4. Crimp which is not well defined & average crinkle
5. No crimp and no crinkle.

Luster is the light reflective quality of the fleece exhibited by the sheen and gloss created as the scales on each individual fiber reflect light. It is a highly desirable characteristic in both handspinning and commercially processed fleeces. Luster is often more obvious when the fleece is on the animal. Off the animal, it can be detected by wrapping a lock over a finger and observing the amount of light reflection.

Contamination or impurities are present in all fleeces to varying degrees, and though not entirely avoidable, they can be reduced through good management. Examples of impurities are: vegetation, sand, dust, stains from urine or vegetation, sweat, and polypropylene. The most bothersome are very fine grass seeds and polypropylene. Polypropylene comes from plastic twine and feed sacks and it cannot be dissolved by chemicals. Often it goes undetected until a final product such as cloth is made. Then, the only way to remove it is by hand with tweezers. Commercial processing is more tolerant of vegetation contamination than handspinners are willing to accept.

Hand or handle is the tactile feel of all the fiber characteristics combined. A fine, dense fleece will usually have a stronger or rougher handle than one that is not as fine and not as dense A sense for handle can only be developed by touching many, many fleeces.

The blowout factor is the rapidity with which an animal's fiber diameter thickens with age, usually and hopefully reaching its peak at about 4 to 5 years of age. This thickening occurs in all animals, but it is the degree that varies. Animals with a low blowout factor retain fiber fineness and are likely to produce this characteristic in their offspring. Alpacas can blowout 5 to 10 microns from birth to maturity. Yearly sampling is helpful in determining an animal's blowout factor. No standards exist for acceptable or expected blowout factors.

Consistency, an often forgotten characteristic, is the uniformity or even distribution of all characteristics within each lock and throughout the entire fleece. It can be observed by parting the fleece on the animal approximately three inches below the topline at the shoulder, the mid-blanket and the rump, and visually comparing the uniformity from area to area. It is quantitatively evaluated by calculating standard deviation and coefficient of variation. Grid sampling can be used to measure consistency. The ideal is for all samples to be the same in micron and color.

All of the above factors are considered individually when evaluating a fleece. The sum total of these factors leads to a final conclusion about the fleece. When using test results as part of a herd selection process, do not accept or reject animals based on test results alone. Test results are an aid in evaluating the visual and tactile judgments made on a fleece. Age of the animal, genetic background, health and feed intake should also be considered when comparing test results.

Last updated on December 5, 1996