Secondary Fibers

Secondary follicles are smaller, more numerous, and grouped around primary follicles, with the grouping being expressed by a ratio called the secondary to primary follicle rratio ("S/P ratio"). The secondary follicles produce only secondary fibers and do not have sweat glands or erector muscles, but do contain a sebaceous gland. Some secondary follicle sheaths allow "derived secondary fibers" to develop along the same sheath, but each follicle can only produce one hair. Note that secondary fibers can be medullated, just as can primaries. The S/P ratio indicates the number of secondary follicles surrounding a primary follicle. This varies between breeds of fiber-producing animals and also within a breed itself. This ratio can be an indicator of density. But, what it really comes down to is how many fibers are actually coming out of those secondary follicles.

Secondary fibers are instrumental in helping alpacas regulate body temperature by providing soft, dense insulation. The vast majority of heat loss in alpacas occurs from the belly region, where alpacas typically have less fiber. As a result, alpacas tend to cush in cold weather to help retain body heat. While the fiber industry focuses on secondary fibers, because they tend to be finer and softer, those fibers do not provide the same degree of protection from the environment as do the guard hairs and other primary fibers. It is also thought that there may be a difference between the primaries and secondaries in terms of durability. Fabrics we wear closer to our body are generally softer, but less durable. Fabrics we wear to shield us against the elements must be more durable. A luxuriously fine alpaca sweater worn next to the body, combined with a less fine and soft, but more durable, alpaca over-coat, may be the ideal compromise. All alpaca fiber has value. The key is to identify the appropriate processing method and end-use for each grade and/or blend of alpaca.