Farmers should know the genetic data for their bulls

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Continuing last week’s article on selecting bulls for the cattle herd, the most important thing the herdsman must do is decide that only bulls that have production data available will be considered for use in the herd. Normally, the data is available as Expected Progeny Differences or EPDs, but some seed stock producers will also have had genetic data on their bulls. The importance of this data is that it is the only way to judge the genetic potential of a young bull and determine what traits he will pass along to his offspring.
Expected Progeny Differences are based on statistical data submitted to a breed association for evaluation and comparison with other animals of the same breed. All major breed associations provide EPDs for animals in their registry. EPDs are available for traits such as calving ease, weaning weight, yearling weight, docility, rib-eye area, etc. These numbers are calculated based on the statistical data available on closely related animals in the breed registry. The more data available the more accurate the EPD will be. Thus along with the reported EPD number there will be an accuracy number. This number will range from .01 to .99 with accuracy increasing as the number gets higher. To illustrate the importance of the accuracy number, the current Angus breed standard for a “Calving Ease” bull, i.e., one that is less likely to have calving problems and to be safe for use on heifers is a bull with a Calving Ease EPD of +7 or higher. Let’s say you buy a bull with a calving ease number of +9 thinking “Wow, I won’t have to get up at night to check heifers to see if they are having trouble calving! The calf will just pop right out!” In reality your ability to sleep at night will depend on the accuracy of the +9 EPD. Statistically, if the young bull only has an accuracy number of .05 the number is +9 plus or minus 7.8. His real EPD is somewhere between +1.2, (bad for sleeping at night) and 16.8. As the accuracy increases this potential variation becomes much smaller; at .50 accuracy it is plus or minus 3.9 making our example bull’s EPD fall somewhere between +5.1 and +12.9. At .95 accuracy the variation is plus or minus 0.4 which means his actual EPD would be somewhere between +8.6 and +9.4 which means you can be confident calving problems will be few and far between.
For young bulls the accuracy number is usually quite low, often less than 0.1, because there is not much data on related animals of that bull. As the bull gets older and more data becomes available on related animals the EPDs may change, but the accuracy will improve. Accuracy is enhanced more by data from offspring of the bull than it is by data from other related animals; siblings, cousins etc. The more indirect the relationship the less accurate the data is for that particular bull’s EPD numbers. For bulls that are brought into commercial herds, the accuracy may not change much because the offspring are raised on one particular farm and very few commercial farmers report production data to the breed association.
With breeds that have genetic testing programs the EPDs will be more accurate, but only if the bull is genetically tested. Genetic testing looks for specific genes that have been correlated to certain characteristics. The breeder may want more money for a genetically tested bull to cover the cost of the testing, but it is well worth it because the buyer of the bull can be much more confident that the traits represented by the EPDs will carry through to the offspring of the bull.
Next time we will review various EPD’s, what they mean to a commercial herd and how they affect the value of a bull.
We will be presenting the second on-line video class on goats and sheep on Tuesday, Dec. 10. This session will cover heath and internal parasites and will run from 7 p.m. to 9 p.m. The webinar is produced by the Purdue University Cooperative Extension Service and will be presented live at the extension office.  
The Marion County Extension District Board will meet Friday, Dec. 6, at noon at the extension office.
There will be a CPH Cattle Sale at Bluegrass Stockyards, Lexington, on Dec. 11. If you need certification paperwork, please call the office as early as possible.
The Marion County Extension Office will be closed for the Holidays from Dec. 25, to Jan. 1.
The Kentucky Fruit and Vegetable Conference will be held Jan. 5-7 at the Embassy Suites Hotel in Lexington. This is an excellent opportunity for commercial growers, Farmers Market participants and others to learn more about the production of produce. The meeting is sponsored by the University of Kentucky, Kentucky State University and the Kentucky Department of Agriculture.
I am planning to attend the American Forage and Grassland Council Annual Meeting Jan. 12-14, in Memphis, Tenn. I was at the meeting last January and found it to be very informative. If you would like information on attending please let me know.
The Kentucky Cattlemen’s Association will hold its Annual Convention Jan. 16-18, in Lexington. In addition to informative programs and Cattle Tradeshow, Marion County farmer Steve Downs will be installed as president of the association for 2014.
We will hold an organizational meeting for a Marion County Beekeepers Association on Wednesday, Jan. 22, at 6:30 p.m. at the extension office. All active beekeepers as well as anybody interested in getting started are invited to attend.  We will discuss the type of organization potential members want, including the educational topics to be pursued. If interested, please call the extension office at 270-692-2421 so we will know if there is sufficient interest to hold a meeting.
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