by: Bill Pendergrass
Beefmaster Breeders United Executive Vice President

The value of artificial insemination (AI) has been documented time after time. Regardless of your operation's breeding program and marketing goals, AI is the most important tool to help you achieve success. In every instance, AI is the quickest means to add the genetic punch to hit your target.

Before you can select a sire, you must know your female(s). Sounds simple, but many people never consider the strengths and weaknesses of their cows. By using all of the resources available you can make a more informed mating decision for your herd. Evaluate your females:


Refers to the physical appearance of an animal. Skeletal structure, muscling, body capacity and general eye appeal are the most obvious traits that we are concerned with. If a cow has certain flaws, such as being post legged for example, knowing which AI sire can correct that fault is vital.

Phenotypic traits to consider:

Weight: Too small, just right or too large?

Frame: Too short, just right or too tall?

Skeletal structure: Post legged and straight shouldered or adequate angle to the hock and a smooth front end with proper slope to the shoulder? Nobody wants cattle that are structurally unsound. Learning how to understand structure is very important.

Body capacity: Deep bodied with a lot of spring of rib or shallow bodied and flat sided?

Muscling: Wide based and thick quartered or narrow made and thin quartered with little muscle expression?

Balance and eye appeal: Balanced, square and generally appealing or unbalanced, coarse fronted, light muscled.

Femininity/Masculinity: Does she look like a bull or a cow?

The best way to know how an AI sire breeds is to see as many progeny as possible (which can be difficult unless you travel widely) or visit with a knowledgeable breeder who is familiar with several sires and their progeny. Face it, mating cows takes a lot of experience and someone who knows the breed. Phenotype is important, because the first impression your animal gives to a prospective buyer will determine how much they will pay for that animal.

New breeders often find it difficult to learn how to visually evaluate cattle. Reach out to extension and vocational agriculture resources on the local level to learn the basics of cattle evaluation. Many county 4-H clubs have livestock judging teams that practice on a regular basis. Ask if you can participate in a workout where you will learn the finer points of visual selection.


Refers to the individual weights submitted to BBU for inclusion into Genetic Evaluations and the resulting EPDs. Performance in its purest sense is pounds at specific ages in an animal's life.

Before you can select an effective AI sire, you must know the performance background and EPDs of your females. Breeders can schedule herd visits with BBU staff to get assistance in understanding and assessing your females' EPDs and performance records. You can also assess your females on the BBU website where you can get the most current EPDs, including their percentile ranking for all of the traits. This first step is at least as important as knowing the phenotypic strengths and weaknesses of your females.

Birth Weight, Weaning Weight and Yearling Weight are the most basic and important weights. Why are these specific weights important? Because they are the primary value drivers the entire beef industry hinges on.

Birth Weight: an indirect measure of calving ease. Large birth weight calves show a high correlation to calving difficulties in research projects. BW EPD is the most accurate tool to select easy calving sires. Birth weight and BW EPD is perhaps the most important trait buyers consider.

Weaning Weight: very important because most commercial cattle are sold by the pound at weaning time. To many cattlemen, weaning weight is at least as important as birth weight because that is where their paycheck comes from. WW EPD is the most accurate tool to select growthier sires.

Yearling Weight: important for two distinct reasons. For terminal purposes, yearling weight indicates the finish weight of steers ready for harvest ... another paycheck-influencing weight. For maternal purposes, yearling weight is an indicator of the mature size of a female. Large females require more feed and pasture for maintenance purposes. Again, YW EPD is the best indicator for yearling weight.

Milk EPD: important because it reflects an animal's ability to produce more pounds of weaning weight. In a highly maternal breed like Beefmaster, many breeders consider breed average for Milk EPD to be ideal. Selecting for too much or too little Milk EPD has consequences. Heavy milking cows require more nutrition for maintenance and breeding and, conversely, light milking cows wean off calves that weigh less. Balance is important in all traits, especially Milk EPD.

Scrotal Circumference: is the only fertility measurement calculated in BBU EPDs. Scrotal circumference (SC) in yearling bulls is highly correlated to the age in puberty in a sire's daughters. The larger the SC, the earlier his daughters come into production, meaning their daughters are more fertile. SC EPD is the most accurate indicator of fertility in Beefmaster cattle.

There are also some important ultrasound carcass measurements to consider. Ultrasound scans are a method to make carcass evaluations on live animals that will be used for breeding purposes. Ultrasound measurements are converted in EPDs and are used like other EPDs in mating decisions.

Fat thickness: FT EPD refers to how much fat cover an animal has over the 12th rib. This is important for Yield Grade calculations on carcasses.

Ribeye area: REA EPD refers to the internal dimension of muscle in the ribeye of a carcass. This is important because REA is a primary driver in Yield Grade equations in carcasses. Larger REA in carcasses is generally good. REA is also considered to be the primary indication of muscling. Light-muscled, over-fat carcasses that earn Yield Grade 4 scores are usually discounted. Selecting for larger REA EPD will rapidly add muscling to your cattle.

IMF: or Intramuscular Fat roughly equates to Marbling or Quality Grade in a carcass. IMF EPD is easily the most accurate means to select for increased marbling. Single trait selecting for IMF should be avoided. Breeders should always balance IMF and REA EPDs together.

Now that you understand the phenotypic strengths and weaknesses of your cows and have also studied their EPD profile, you are ready to start mating your cows. There is an art and science associated with mating cattle. There is no single sire that does it all.

Remember, there are three kinds of cattle out there:

Type #1 has great phenotype and little or no performance information. Perhaps someone will like them and pay good money.

Type #2 has great performance and EPDs but the phenotype is marginal. Perhaps someone will like them and pay good money.

Type #3 has great phenotype and good performance, EPDs and ultrasound data. These are the cattle that sell for the most money ... time after time.

(Reprinted with permission from the March 2015 Beefmaster Cowman.)

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