Utilizing Genetics in the Bull Selection Process  

March, 2022
Kalan Royal, UF/IFAS Extension Highlands County, Sebring

Cattle producers must make many important management decisions throughout the year, such as selecting a herd sire. Bulls are responsible for the largest proportion of calf crop genetics each year. Purchasing bulls based on phenotype is still a common practice; however, utilizing Expected Progeny Differences (EPDs) during the selection process can help producers meet the goals of their operation by offering a guide to the genetic potential of a bull. The impact a bull can have on an operation is profound, therefore value should be placed in understanding evaluation tools that are available to use in the selection process.

When buying a bull, the objective of the cattle producer should be to purchase an animal that is going to improve the genetics of his offspring. Selecting bulls based solely on physical appearance or raw phenotypes (actual weights) fails to factor in environmental influences while overlooking the genetic potential of a bull. Environmental influences such as feed and forage availability and herd management do not get passed on to the bull’s offspring. The addition of EPDs in the selection process can quantify genetic differences that will be passed down to the calf crop.

Expected Progeny Differences (EPDs) provide an estimate of the transmitting ability of a parent to its offspring. EPDs allow producers to predict how future progeny of a sire are expected to perform compared to the progeny of other sires within a breed regardless of age or location of the animal(s). Purebred cattle producers provide data and information to their respective breed associations that is used to calculate EPDs. Data submitted from the actual performance of an animal, an animal’s progeny performance, the performance of indirect relatives (brothers and sisters) and information from an animal’s ancestry are used when calculating EPDs. The genetic makeup of an animal will never change but the amount of information we know can change, therefore the more data gathered on a bull the greater the accuracy of EPDs becomes. Accuracy (ACC) is improved as data is submitted providing bull buyers with an increased level of confidence for the genetic merit of a sire by reflecting the precision of specific EPD traits. Accuracy will be displayed under EPDs on the chart and are displayed on a scale of 0 – 1.

Carcass, maternal and performance traits are all measured by EPDs. When looking at EPDs single trait selection is dangerous and can have negative consequences. Selection for extremes in any direction for any given trait can change affect reproduction efficiency. Traits should be selected based off economic importance to the operation that align with the goals of the operation.

Cattle operations that are marketing or retaining replacement heifers will more than likely focus on maternal traits such as Calving Ease Maternal (CEM), Heifer Pregnancy (HP) and Stayability (Stay) along with Birth Weight (BW) and Calving Ease (CE). Producers that retain ownership of cattle through the feedlot will probably add value to Carcass Weight (CW), Marbling (Marb), Yield Grade (YG) and Ribeye Area (REA) during selection along with Birth Weight (BW) and Weaning Weight (WW).  Breed associations display this information differently, so it is recommended to find an EPD guide specific to the breed.

Breed associations have also began adding selection indices which were designed to match production goals of an operation. A selection index will include a set of traits that have been determined as having production importance. Research is done by the breed associations to understand which individual traits should be included in the index. Examples of selection indices would be Fertility Index (FI) and Terminal Index (TI) indices that the International Brangus Breeders Association provides or the Terminal Sire Index (TSI) the American International Charolais Association provides. The utilization of a selection index when comparing potential herd sires gives producers the ability to evaluate a single number that has combined several traits of value to meet a focused goal rather than individual comparison of traditional EPDs.

Genomic-enhanced EPDs (GE-EPDs) utilize DNA information collected from bulls to provide an increased reliability of EPDs. GE-EPDs improve accuracy of EPDs, especially in young bulls who have no progeny. Genomics can provide information to reflect the equivalent of around 10 progeny records, depending on the trait, for a young bull.

It is important to remember that EPDs allow for comparisons of bulls within the same breed. This information is displayed as a number so buyers should understand how to read these numbers and what the breed averages are. Below the EPDs there are typically two additional rows of information. The first is Accuracy (ACC) which increases by data submitted on the progeny of an animal or DNA testing and the second being % Rank which allows producers to compare bulls within the breed. The U.S. Meat Animal Research Center publishes an Across-Breed EPD (ABEPD) table yearly providing adjustment factors to create a common EPD scale that can be used to evaluate bulls of different breeds.  

Expected Progeny Differences (EPDs) are a valuable tool that cattle producers both commercial and purebred, should take advantage of when making their next bull selection. EPDs allow producers an insight on the genetic potential an animal can pass on to his offspring. Setting clear goals for the operation will influence the traits that are of importance for the producer to meet their production goals. Cattle performance is influenced by the environment and genetics. Regardless of how good the EPDs are, bulls must be structurally sound and pass breeding soundness exam as reproduction is the goal of purchasing bulls. Utilizing every tool available in the selection process gives producers the ability to meet the goals of the operation and buy bulls with an added confidence of what they are getting.


Return to top