By Dr Clive Dalton
Staples of kid fleece, 26-30 micronsGoat fibre
- Fibres start to grow in the foetus from follicles in the skin.
- The first to develop are large coarse fibres from primary follicles, and finer fibres follow these from secondary follicles.
- A typical group of these follicles would be made up of three primaries and 20-30 secondaries in a mohair goat.
- This is called the Secondary/Primary (S/P) ratio.
- Birth coats are rich in coarse fibres but are shed at about three months old leaving fine fibres from the secondary follicles to produce the first fleece.
- Fleeces generally become coarser with age as the primary follicles continue to produce and shed coarse fibres, especially during spring and autumn.
- Mohair is the fibre produced by Angora goats.
- Angora rabbits produce fibre called “Angora”.
- Mohair is classed as a luxury fibre and is mainly used in blends to make clothing and furnishings.
- Annual mohair fleece weight from kids averages around 1kg, and 2-3kg from adult does.
- Fibres range in length from 100-175mm and are white with high lustre.
- Mean fibre diameter ranges are:
- Superfine kid (23 microns or less)
- Fine kid (23-27 microns)
- Young goat (27-30 microns)
- Adult hair (30-33 microns)
- Strong adult hair (33 microns or above)
- Mohair can in theory contain up to four fibre types:
- Non-medullated fibres (the best quality to aim for).
- Non-medullated fibres with medullated tips.
- Medullated fibres.
- High quality mohair today contains little or no medullated or kemp fibres.
The broad grading divisions are:
- Fine: Soft handling and lustrous premium fibre. Only 5% of total fibre qualifies for this premium quality grade. NZ kid is in this grade.
- Medium fine: Soft handling and lustrous. Young goat qualifies for this grade.
- Medium: Lustrous with reasonable handle from adult goats.
- Strong mohair: Coarser fibre from adult animals.
- Kempy mohair: Can be quality mohair but rich in kemps which severely downgrades the fibre.
- Fineness: Measured by mean fibre diameter in microns (millionth part of a metre). Fibres become coarser as the animal ages.
- Staple length: The length of the shorn staple. This is the most important characteristic in manufacturing.
- Uniformity of fibre: High quality fibres should be uniform along their length. Fibres of 130mm long are used for worsted yarns and under 100mm for woollen yarns.
- Tenderness or break: Refers to weakness in the fibre usually caused by low plane of nutrition. The fibre will break at the weak point during manufacturing greatly reducing its value.
- Medullation: Fibres with a cavity in the core filled with air or loosely packed cells. There are two types:
- Gare (kemp) fibres which grow continuously.
- Kemp fibres which grow for shorter periods and are held within an inactive follicle for a period prior to shedding.
- Lustre: The sheen caused by the large cuticle sized scales on the mohair fibre reflecting light. These are much larger than on wool.
- Softness & Handle: The flatter alignment of mohair cuticle scales gives mohair a softer feel. It is dictated a lot by fibre diameter – the finer the fibre the softer it feels.
- Colour: White is the preferred colour as the fibre can then take any colour dye. Yellow discolouration from wet weather is a common New Zealand defect.
- Yolk: Secretion from glands in the follicle. This is very low in the goat so after scouring you get at high yield of at least 90% clean fibre.
- Style & character: Good style is a combination of fineness, evenness, soft handling, and lustre and good staple formation. The degree of crimp (twist or wave) in the staple is important in this trait. Gives good aesthetic appeal but does not influence processing and has little effect on price. Some breeders consider high crimp to be more immune to adverse weather effects.
- There are over 20 different mohair lines which are designed to meet the very precise needs of the processors and their markets.
White is preferred but some natural colours such as this 'bark' is popular for handcrafting.
Combed top 26-30 microns
- Cashmere fibre is described as soft, luxurious, hard wearing providing soft handle, lightness and warmth.
- It‘s the fine undercoat that can be found in all types of goats which grows among the coarse outer guard hairs to provide a warm undercoat.
- In goats specially bred for the fibre, the number of these fine fibres have been increased and these are separated after shearing by blowing air over the fleece leaving the guard hairs behind.
- Feral does will produce 20-70g of fibre, and with selection animals producing 100-150g were identified. Yields of 250g and up to 500g were talked of when cashmere breeding was at its height in the 1980s.
- Mean fibre diameter is 15-16 microns with a range from 8-18 microns. The down is non-medullated and ranges in length from 50-55mm. The fibres have no crimp and no grease.
- This fibre comes from crosses between Angora and cashmere goats and is generally around 20 microns.
- These are the medullated fibres found on all goats except Angoras and can vary from 40-140 microns in diameter.
- They grow from the large primary follicles in the skin.
- Goat hair is used for felts, cords, carpets and brushes and to produce fancy effects in tweeds.