The objective of our breeding program is to increase the density and length of fibers grown by our alpacas. If there are many fibers on the animal’s body and these fibers are long, then the alpaca will produce a high fleece weight. Also, since high fiber (follicle) density is genetically correlated with low fiber diameter, the fleece will have a high value because it is fine and there is a lot of it.
Follicle and Fiber Patterns
Fibers grow from follicles in the skin. Follicles develop before the cria is born. Primary follicles form first and then the secondary follicles. All are arranged as follicle groups.
There are only three primary follicles per group. The number of secondary follicle is much higher and is a genetic characteristic for a particular alpaca but can vary widely between animals (According to according to Dr. James Watts-from 17-50). The S/P ratio, or the ratio of secondary follicles to each primary follicle, defines the number of follicles per group.
Adult alpacas considered of good fleece quality by current industry standards have, on average, an S/P ratio of 10 to 1 and about 40 follicles per square millimeter. Primary fibers are usually no more than 10 microns coarser than the average diameter of the secondary fibers. The average diameter of the secondary fibers is usually less than 25 microns. The length growth rate of the fibers of adult alpacas of less than 4 years of age is at least 0.35 millimeters per day.
As the follicle density increases, the primary fibers are so fine as to be so fine as to be indistinguishable from the secondary fibers. This is an important point. Primary fibers need to reduce in size (by selective breeding) in order for the number of follicles per group (expressed as the S/P ratio) and the follicle density (expressed as follicle per square millimeter) to increase. By reducing primary fiber diameter, ‘guard hair’ is also eventually eliminated as all fibers will be uniform in size and shape.
It is certainly possible to breed animals that are a lot denser, finer and longer than the current standards.
Medullated and Pigmented Fibers
In horizontal skin sections, medullated and pigmented fibers can be identified and counted within each follicle type.
Medullated fibers and pigmented fibers (in white alpacas) are unwanted fibers which spoil the appearance of fabrics. While modulation is found predominately in primary fibers, secondary fibers can also be affected. And while, meduallation tends to disappear as the fibers become finer, this is not always the case. In some animals, medullated fibers can still be present in fine diameter fibers and numerous among the secondary fibers.
Skin testing allows us to identify, and remove from the breeding pool, animals with these hidden problems.
Breeding Comments (Dr. James Watts)
Arctic legacy: The alpaca has high follicle (fiber) density. The secondary fibers are fine and uniform in diameter. The follicle groups contain high numbers of wool follicles. This is a male with high fiber density and length that would be expected to breed well for fleece traits. Best joined to females to continue to reduce primary fiber diameter and to try to remove any sign of ‘guard hair’ in progeny.
White Lightening: The alpaca has moderate follicle density. The primary fibers are relatively uniform in diameter and the secondary fibers are fine, uniform and mostly free on medualltion. Good density and fiber uniformity. Likely to breed well for fleece traits.
Royal Accent: The alpaca a high follicle density. The primary fibers are high and variable in diameter. The secondary fibers are uniform and mostly free of medullation. The follicle groups contain high numbers of wool follicles. A high density male which should breed well for fleece traits, especially to fine fleeced females.
Pure Luck: The alpaca has high follicle (fiber) density. The primary fibers are relatively fine and uniform in diameter. The secondary fibers are fine in diamteter. The follicle groups contain high numbers of wool follicles. Good density and length levels for an older male with excellent fiber uniformity characterized by low primary diameter. Would expect the animal to breed well for fleece traits.
Density and Length Profiles |
