LIMOUSIN TODAY October_LimToday_WEB - Page 19

Performance Line Genomic Testing Females is an Investment in your Genetic Future By Tonya Amen, National Center for Beef Excellence If you’ve been breeding cattle long, you are aware of the costs associated with either raising or buying your replacement females. Yet, through the years, we’ve often placed more emphasis on bull selection. This is not without reason, of course, as bulls do contribute heavily to the genetic value of the herd each year. But, over her lifetime, a female can also leave a big mark on the genetic value of a herd. Genomic traits tests like the HD, LD, and uLD tests offered through GeneSeek and Zoetis are used in seedstock for two primary reasons: 1) to improve the accuracy selection through increased accuracy of EPDs or 2) for marketing purposes. Due to the impact of sires on genetic improvement and because, in seedstock operations, selling bulls is often the main income source, most breeders who decide to invest in genomic technology understandably start with the bulls. However, I’d like to present the case that females are also important candidates for testing. Table 1 shows the progeny equivalents for traits currently evaluated in the North American Limousin Foundation’s National Cattle Evaluation powered by BOLT. Progeny equivalents illustrate the average number of progeny that would have to be measured for a particular trait to achieve the level of accuracy delivered on by a genomic test on young, genotyped, non-parents. For example, for a non- parent bull to achieve the level of accuracy delivered by a genomic test for CED, a breeder would have to submit calving scores on 15 heifers whose calves were sired by him. For yearling weight, a breeder would need to submit 24 yearling weight on his progeny to achieve the level of accuracy expected by genomic testing. Now, think about genomic testing heifers instead of the non-parent bull; a genomic test will deliver more accuracy on her EPDs than if you submitted performance data for all the natural- service calves she has in her lifetime. What a tremendous investment in the genetic future of your herd! Not only will testing your females improve the accuracy of selection when it comes time to make your replacement heifer choices, but it will also help insure that you make the best mating choices when breeding time rolls around. By adding accuracy to her EPDs before the heifer is bred, you’ll get a truer picture of her genetic strengths and weaknesses, which will give you better information when