Genetics
Although genetic-evaluation programs are new to the goat industry, producers have used information from these types of programs for many years to make genetic improvements. Most genetic-evaluation programs are managed by breed associations and are used to compare registered animals within the breed. Breeders collect individual animal performance measures and submit it to the breed association managing the program. Then, the information submitted for an animal and all of its relatives can be used to predict future offspring performance. Most of the major sheep breeds, including the Katahdin, have a breed-improvement program in place, and some Boer and Kiko goat associations have also started genetic-evaluation programs.
Genetic-evaluation programs can help produce unbiased information for selection of breeding stock such as Expected Progeny Differences (EPDs). An EPD is a numerical estimate of the value of an animal for one specific trait; it tells us the possible differences of a goats offspring compared to the average of the breed. So, genetic-evaluation programs can help:
1. Identify and document genetic merit/value for major economically important traits,
2. Predict possible performance of the next generation,
3. Provide breeders with EPDs to be used as another tool in selecting breeding stock,
4. Provide paperwork and information to customers about what breeding stock to buy.
The EPD for a young animal will be mostly based on its parents’ performance records such as birth, weaning, and/or yearling weights. After the kid’s own performance records have been processed, its EPD will be based on a combination of its parents’ records and its own performance. If that kid is selected as a breeding animal, and records on its kids are reported, the records on its progeny will also be used to calculate its EPD. Because all relationships among animals (parent-offspring, half-siblings, cousins) are taken into account, older animals or those with a lot of relatives in the program will have more accurate EPDs.
Producers can compare goats using EPDs. For example, a buck with a weaning weight EPD of +1.0 pounds (meaning his offspring should be 1 pound heavier at weaning than average) is good, but a different buck with a weaning weight EPD of +2.0 pounds is better. EPDs give the most unbiased estimation of genetic value possible. The EPDs provided by a breed association will vary. The most common EPDs usually reported include the following:
- Birth weight EPD
- Maternal birth weight EPD
- 90-day weaning weight EPD
- 150-day post-weaning weight EPD
- Maternal milk EPD
- Milk plus growth EPD
- Number born, or percent kid crop
- Carcass EPD
- Reproduction EPD
- Production life EPD
The breed association calculating the EPDs can provide more information on genetic animal evaluation programs and how to use EPDs as a selection tool to meet production goals. Participating in an EPD program can provide producers with more information for their own herd, and can also give producers a marketing edge for selling breeding stock.
Adapted from www.luresext.edu.