Objective measurement of cashmere and its role in breeding programmes
(by Dr Margaret Merchant, MLURI, Scotland, UK)
The value of cashmere is determined by a whole range of characteristics which in the past were evaluated by the eye of an expert with many years of experience in the trade. The task was, and still is, to assess the amount of usable cashmere available in the undercoat, to determine the quality and the potential end use of cashmere and to estimate the cost of processing it into the finished product.Characteristics of cashmere which are assessed include:
The variability in each of these components is also important as is the character of the guard hair which should be long and coarse for easy and effective removal and to protect the undercoat while in situ.
Objective measurements for many of these traits have been established and developed into IWTO (International Wool Testing Organisation) specifications (the main exceptions being colour and lustre) which buyers rely upon increasingly to purchase fibre. Objective measurements also provide the means by which the requirements of the trade can be translated into goals for the producer and breeder.
The differential in the price paid for cashmere is variable but is always in favour of fine white cashmere with high crimp and low lustre and the production of such high quality fibre must be the ultimate goal of European cashmere breeders. However, the breeder has the additional task of increasing annual production per head since financial returns are determined not only by price/kg, but also by weight produced. Fibre traits such as fibre diameter and annual production, in cashmere goats are very strongly inherited (Sumner and Bigham, 1993; Bishop and Russel, 1996) but there is, as in other fibre producing species, a positive relationship between fibre diameter and fibre weight which prevents concurrent improvement in annual production and fibre quality. Devising a strategy to overcome this problem is the current challenge for researchers and breeders alike, but most breeders or even breeding groups in Europe currently operate on a small scale limiting the amount of information available and progress which can be made. One important aim of this Thematic Network, which is to be commended, is to establish common protocols for fibre analyses so that performance records from herds across Europe can be merged into a common database for the eventual benefit of all participants.
In any breeding programme, the rate of genetic progress is faster with selection for fewer traits in larger numbers of animals. In the past, the hand separation of patch samples to determine cashmere yield and estimate annual production, and the projection microscope technique for the measurement of fibre diameter, was expensive in terms of time and money. It limited not only the number of traits which could be measured but also the number of animals which could be tested. With the use of OFDA, we can not only measure fibre diameter more accurately, but we can also measure yield (Herrman and Wortmann, 1997) in a fraction of time, sparing resources to measure other traits such as length, colour and crimp, which can be included in the cashmere database.
With the best European cashmere goats, currently producing 250g of hosiery or 300g of weaving quality cashmere, and the average goat producing closer to 100g, selection for increased annual production of cashmere under 18.5 mm, using measurements of yield and diameter, is likely to be a priority for the foreseeable future. However, information in the database will enable us to develop efficient selection strategies for other traits, if these become important. The first step is to decide what we want to measure and to establish a common protocol and standard of measurement. The data is only as good as we make it.
Bishop, S.C. and Russel, A.J.F., 1996. The inheritance of fibre traits in a crossbred population of cashmere goats. Animal Science 63: 429-436.
Herrmann, S. and Wortmann, F.J., 1997. Opportunities for the simultaneous estimation of essential fleece parameters in raw cashmere fleeces. Livestock Production Science 48: 1-12.
Sumner, R.M.W. and Bigham, M.L., 1993. Biology of fibre growth and possible genetic and non-genetic means of influencing fibre growth in sheep and goats-a review. Livestock Production Science 33: 1-29.
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