The average cashmere yield from feral goats is 20 per cent, but superior, bred on animals have yields up to 45 per cent cashmere. Cashmere yield is determined using special machinery that separates down from guard hair. The down is affected by ultraviolet rays which damage the exposed tips, causing brittleness. This reduces length during combing. Guard hair length should exceed the maximum down length to protect the down from weathering and harmful ultraviolet rays.
Feral goats can have either short, medium or long guard hair.
There is no evidence that guard hair length is related to quantity of cashmere production. Down is produced in a range of colours, from white, to light grey through to dark grey and brown. White is most desirable giving the widest range of alternatives at the dyeing stage. Cashmere colour often contrasts with the colour of the guard hair. Fibre diameter Cashmere has a mean fibre diameter between 11 and 18 microns with no down fibre above 28 microns.