Recognising Basic Fibre Types
Recognition of the various two-coated fleece types that fall within the cashmere range, is basic to animal selection, mating programmes, and on-the-board fleece classing.
This note presents the various fleece types found throughout Australia's cashmere herds. Because of the mixed genetic background of many goat herds, more than one of the following basic fleece types will probably be present in any one herd.
To simplify the description, the most typical fleece types are put into five categories. These types may be identified on animals over two years of age where the mature fleece is present.
Spectrum of fibre types, which are most commonly found in a cashmere flock. These five categories range from superfine, short, crinkled fleece to straight lustrous fleece. The illustration shows from left to right the tendency for a gradation in length and a tendency for the fibre character (crinkled/straight) to become plainer and straight as the fibre becomes coarser.
TABLE 1. - Five basic fleece types that appear within a cashmere flock. Note that "Medium" and the finer "Strong" fibre has been marketed as a single line, whilst the rest has gone to cashgora, to suit buyer preferences.
Cashmere classing lines.
Cashmere is the fine undercoat produced by many goats. White down gives the greatest monetary return to the grower, since "white" may be dyed to any of the palest to strong shades. Other down may vary from silver to shades of grey, ginger and brown. Brown down, when dyed, gives a lovely colour resonance to the darker shades.
Superfine cashmere is most often found on young animals. It may be the intensely delicate fibre on a long haired goat, or on an animal with a soft "cushiony" handle and a shortish fleece. When shorn, and the fibre is on the table, it is very soft to handle and usually not longer than 50mm. When a pinch of fibre is taken, the down fibre when drawn from the hair appears to be scarcely affected by gravity and will float gently upright in still air.
Fine and medium cashmere will have varying degrees of crinkle, and between 35-100mm length. They are best distinguished by the softness of handle, the degree of crinkle, and the degree of floatation in still air. Experience combined with testing fleeces is the only way to learn.
Strong cashmere, which is over 18.5 micron, is not regarded by international standards as cashmere, and is marketed by the ACGA as cashgora. Sometimes it handles as medium cashmere, but the finished article does not handle as cashmere, and is generally not acceptable to the processors.
Cashgora is typically seen as the shiny fibre in a fleece, often around the neck. It is a hybrid fibre between cashmere and mohair, and exhibits different dehairing, dying and spinning properties to both cashmere and mohair. It may test as "fine fibre", but because of the intermediate fibre it cannot be classed as cashmere. This third fibre clearly delineates cashgora.
Visual Assessment of the Fibre on the goat.
Once the grower can recognise the fibre types on the goat, this can be used to class the herd and fibre at shearing.To assess the down fibres, the staple should be plucked from its base at skin level, and then held up to the light. It is important to tease out the sample well so down character and diameter, hair diameter and separation between the fibres can be seen.
If the fleece is examined at the end of each successive fleece season, changes will be observed during the goat's lifetime. Patterns will emerge, such as goats that are medium fleeced as two year olds which were fine/superfine as kids. Each coat may exhibit more than one basic fibre type within its fleece.
Other observations and Causes of variation.
1. Within fleece variation. There is a gradation in diameter across the body so that the coarsest fibre with the greatest diameter distribution tends to occur on the neck. This is the opposite to the fleece of the sheep. In some animals the fibre on the neck is long and lustrous, while the fibre on the hind legs is finer with coarser guard hair.
2. Age. Kid fleece is usually finer than mature goats and has finer guard hairs. Some goats coarsen more as they mature than others. For this reason, classing of mature fleece is more relevant and comparisons must be made within age groups.
3. Reproductive Status. Fleece evaluation must always take the reproductive status of animals into account. Fleece growth on does will often not commence until kids are weaned. Udder scoring at weaning to "wet" and "dry" the does is an important management aid and will highlight the different fleece growth seen between does that have/have not produced. Working bucks will also have their fleece growth affected and may shed during or after the joining period.
4.Guard Hair. Coarse guard hair is most desirable due to the ease of removing it during processing. In general the coarser the down fibres, the finer the guard hair. As down weights increase, the problem of fine guard hair may also increase.
5. Growth Cycle. The basic growth cycle is thought to be controlled by daylength and grows between the longest and shortest days of the year. Nevertheless, it would appear that in some goats bred for cashmere, this basic biological rhythm becomes modified so that they grow cashmere all year around. Such animals are referred to as "continuously growing". The growth cycle has a profound effect on the quality of cashmere present as the cycle progresses during the year. The mean fibre diameter is observed to be coarsest during the summer months and is finest just before shedding commences at the end of the growth cycle, as the finest fibres do not grow until late in the season.
© 2000 A.C.G.A.