More Than EPDs in Sire Summaries: Both purebred and commercial beef producers have become adept at using EPDs in the selection of herd sires and other seedstock. The major traits of interest are birth weight, weaning weight, maternal milk, and yearling weight. EPDs, in most breed associations however, are available on a number of other traits including maternal weaning weight, yearling hip height, scrotal circumference, and carcass traits including carcass weight, marbling, ribeye area, fat thickness, and percent retail product. Other traits available from various breed association sire summaries include calving eaves heifers and mature cows, mature daughter weight, and mature daughter height. EPDs are indeed extremely useful in comparing animals within a breed. All EPDs are also reported with accuracy, which give us an indication of the change that may be expected when more records are added. In other words, accuracy can range from 0 to 1.0 and the higher the accuracy, the more dependable the EPDs for any trait. Unproven non-parent bulls or females will have accuracy up to about .3. Accuracy on these animals will depend upon the amount of data on sires, dams, and collateral relatives. The more data, the more accuracy. Bulls to be considered proven must have accuracy on various traits of at least .8, and the very highly accurate bulls by virtue of having lots of progeny records will range between .95 and .99. Usually breeders who plan to select sires for use through artificial insemination prefer these high accuracy bulls and should. The other information that is often times under-utilized is the percentile rank for each trait EPD of any animal. The percentile rank within the particular breed may be obtained from the tables in the front of the sire summary. Animals whose EPDs for any trait are average for that breed will have a percentile rank of 50%. Those above average will have a higher percentile number, but will really show a lower percentile. For example, in the Angus breed for non-parent bulls born in 1996, the average weaning weight is 29 pounds or 50%. A bull with a weaning weight EPD of 38 pounds is in the top 10 percentile. I have found it very interesting to use Roy Wallace's "power index" in evaluating the four major traits based on EPD percentile rank. The way this works is to look up the percentile for each of the four major traits of birth weight, weaning weight, maternal milk, and yearling weight. Add these percentiles together and divide by 4 to get the average. This "power index" is very useful in making an evaluation of animals such as bulls in a sale.
Sire summaries made available at no cost from national breed associations can be obtained simply for making a request to the association or associations of interest. They will mail sire summaries for the asking. Listed here are a number of these associations: American Angus Association, 3201 Frederick Blvd., St. Joseph, Missouri, 64506; American Gelbvieh Association, 10900 Dover Street, West Minster, Colorado, 80021; American Hereford Association, P.O. Box 014059, Kansas City, Missouri, 64101; American International Charolais Association, P.O. Box 20247, Kansas City, Missouri, 64195; American Salers Association, 5600 South Quebec, Suite 220 A, Englewood, Colorado, 80111; American Shorthorn Association, 8288 Hascall Street, Omaha, Nebraska, 68124; American Simmental Association, 1 Simmental Way, Bozeman, Montana, 59715; American Tarentaise Association, P.O. Box 34705, 1912 Clay Street, North Kansas City, Missouri, 64116; Beefmaster Breeders Universal, 6800 Park Ten Blvd., Suite 290, W. San Antonio, Texas 78213; North American Limousin Foundation, P.O. Box 4467, Englewood, Colorado, 80155; Red Angus Association of America, 4201 I-35 North, Denton, Texas 76207-3415.