Cashmere Genetics

Science has established the genetic correlations among goats in a population. Researchers have developed tools that allow us to achieve our goals. It’s not rocket science; it is a methodical collection of data that can be assembled into a data set. Want to know how to get to where you want to go?

Genetics is the study of the genotype or genetic makeup of an animal at the chromosomal level. Population genetics deals with the behavior of genes in populations and those forces that change gene frequency (Pattie & Restall, 1991). Populations tend to evolve continuously as a reaction to environmental conditions. Populations that are isolated tend to express those genetic changes faster than those populations subject to constant gene in-flow from neighboring populations. Various “breeds” of goats may simply be a result of geographic isolation and color dominance. Only DNA testing can determine if there are genetic differences between the various groups. But for the purposes of this Breeding Program, we will assume that there are no significant differences in genetic make-up between goat populations and therefore there will be no difference in their response to genetic manipulation due to differences in “breed”.

The problem with cashmere goats is that we are not dealing with simple Mendelian genetics. There are multiple alleles with multiple loci that determine the expression of many of the genetic traits we wish to control. Color, for example, may be controlled by four alleles alone. What we will be dealing with is called quantitative genetics. According to Pattie and Restall (1991), quantitative genetics is “the operational science of animal breeding; many genes, each with small effects, control traits that are completely inherited.” Their work, which spanned over 20 years from the late 70s to the late 90s, studied six thousand Australian feral and selected cashmere-bearing goats. Studies of this magnitude have not been undertaken anywhere else in the world. As a result of this research, Pattie and Restall have established specific heritabilities and correlations between the six basic cashmere characteristics: length, micron, fiber weight, yield, fleece weight and liveweight.

The effect of environment should not be a factor in a Breeding Program design. According to Pattie and Restall, at every environmental level there will be genetic differences between breeds, cross breeds and individuals. We do not need to spend resources improving management and nutrition until the animals express their genetic potential before we begin to upgrade the genetics. In other words, the effect of environment will be approximately the same upon each group so changes will still be observed after genetic manipulation is attempted. But, it is very important to limit the number of traits to be manipulated to 1 or 2 in order to maximize progress. Pattie and Restall have published a book, “Breeding Cashmere Goats” (1991) which lays out the basics of cashmere goat breeding at the herder level. It is the goal of a Breeding Program to teach tbreeders how to use the tools that Pattie and Restall have provided. This entails careful measurement of the fiber characteristics mentioned above as well as several body measurements. These values can then be mathematically manipulated according to a “selection index” that will identify the best buck to use to achieve the breeder’s goals. The key is to have the breeder be able to:

1) Define their own objectives based upon the current herd statistics
2) Conduct their own genetic evaluation by doing the actual measurements
3) Implement a breeding program.

This is not rocket science, but it is scientific. A Tiered Breeding Structure (also called a nucleus herd breeding scheme) is probably the breeding program of choice as it uses only selected bucks from a nucleus buck herd over does that have likewise been selected for their quality. This requires that groups of selected does be maintained and it works best within a cooperative group of breeders. Use of an Independent Culling Level selection system is the next best method to improve a cashmere goat herd and this system will be used wherever it is not possible to set up a Tiered Breeding Structure. This secondary system will result in about a 15% reduction in the rate of improvement, but it is much easier to implement within a single family herd.

The first place to start is with the spring harvest season. Careful cashmere harvesting will allow each breeder to record his herd in terms of goat bodyweight, down production, down length, and down diameter. This will allow him or her to better define the breeding buck that will be needed in the fall as well being able to market his/her cashmere based on known fiber type. How to select an elite herd from within an existing doe herd efficiently is a skill that the breeders must learn.

The second obvious place to start, one which should immediately improve income to the breeder, is for him or her to class fiber into “lines”. A line is a bag or group of bags that contain like fiber; fiber that is all the same color and quality. Quality is defined by micron diameter and yield (% of guard hair vs. fiber). This will come easily with breeder education and it is also part of the data collection process involved with cashmere data collection. Classing fiber into lines based on quality should give the breeder more leverage in the marketplace. The best thing that could happen in the short run is for the breeders to become educated in the market economics of the cashmere industry as well as the mechanics of manipulating cashmere herd statistics. This will allow the breeder to make educated breeding decisions that will directly affect his income. Again, the objective of the Breeding Program is to give the breeders tools with which they can manipulate their herd statistics. The way in which they choose to use these tools is up to them.

Nutrition plays such an important role in cashmere quality and quantity, a basic knowledge of the goats’ nutritional requirements is also part of the program. Additional tools are designed to help the breeder. Various conformation defects that can and do affect survivability and reproductivity are discussed. Animals that cannot compete effectively because of a physical deformity are more likely to die and are more likely to be non-reproductive (dry). Furthermore, while they are alive, they consume feed which is in short supply, depriving their herdmates of that resource; herdmates that will be adversely affected by this lack of nutrition. Thirdly, non-reproductive goats are liable to be more aggressive and can physically harm productive herd mates. Defective goats, goats that grow fiber that is not within the definition of cashmere, old goats, wethered goats and female goats that are unlikely to reproduce should not be maintained within an elite herd.

Basic Cashmere Classing, a necessary tool, teaches the fundamentals of identifying cashmere as to color and quality. As a market for quality cashmere goes up, breeders will have to know what it is that they are trying to market in order to command the highest price possible. But breeding programs are also notoriously slow, requiring two to three generational intervals to realize monetary gain. A generational interval is defined as the time it takes to completely turn over herds’ genetics. It is calculated by figuring the average age of the bucks used for breeding, adding that to the average age of the does that are kidding and dividing by two. If bucks are first used at age 2 and are used until age 6 (4 years) and does begin to kid at age 2 and are kidding until the age of 6 to 8 years (a total of 4 to 6 years), the generational interval ranges from 4 to 5 years [((6-2)+(7-2))/2=4.5]. This means that the results of using an “improved” buck will not be seen in the herd average for up to 5 years after the buck is first used. It is possible to shorten this generational interval to 2.5 years by using bucks for only two years and by culling all breeding does over the age of 4 years. Results will be realized much more quickly if this is done. So if breeders can be content to plan for the long term, they should begin now and plan ahead by instituting a solid breeding program now.

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