Livestock: February 2000 Other Livestock Articles

A question of paramount importance to cattle producers is Which bull is right for my production system? Selecting the "right" bull can potentially contribute more to the genetic improvement and profitability of a cow-calf operation than any other management practice.

Breed: If you are uncertain about the breed of bull to purchase, consider these factors: market acceptance of the product you are selling, availability of potential herd sires, and breed compatibility with your cow herd and production environment.

Age: There is an ongoing debate concerning the age bulls should be when a producer purchases them. Purchasing yearling bulls seems to offer some initial economic advantage, because their initial cost may be lower than that of two-year-olds, but yearling bulls must be managed to allow continued growth and development, which increases cost. Two-year-old bulls typically are more expensive but are usually able to service more cows and require less supplemental feed. As long as one understands the trade-offs between two-year-olds and yearlings, either can be an economically feasible option.

Keep in mind that both breed and age can affect bull fertility, and familiarize yourself with the typical age at sexual maturity for the specific breed you are considering. It is imperative for any bull to have passed a breeding soundness evaluation that checks his physical soundness, scrotal circumference measurement, and semen quality within thirty days of purchase.

Once you determine breed and age, select bulls by using four tools: phenotype, pedigree, expected progeny differences (EPDs), and individual performance.

Phenotype
Phenotype is the visible properties of an animal. Each of us can visualize the ideal phenotype of a bull. However, chances are that we have never seen this ideal animal, much less had the opportunity to purchase it. Therefore, we must compromise when selecting the phenotype of a particular bull. Correctness of feet and legs, muscle thickness, and masculinity are a few of the phenotypic traits that one should consider. Lameness or structural problems are among the leading reasons for culling bulls.

Although disposition is not actually a phenotypic characteristic, one should certainly evaluate it in all potential herd bulls. There are entirely too many bulls available to risk buying a bull with a bad disposition.

Pedigree
Many commercial bull buyers tend to ignore the pedigree of an animal because it is going on commercial cows, but knowledge of pedigree allows more predictable, consistent offspring. If you as a commercial breeder are unfamiliar with a particular breed's pedigree, contact a reputable breeder, breed representative, or breed association for additional information. Familiarization with breed pedigrees can certainly pay dividends in commercial cow-calf production.

Expected progeny differences (EPDs)
EPDs are defined by the Beef Improvement Federation as the difference in performance to be expected from progeny of a particular sire compared to the expected progeny of the average bull in the same breed. EPDs do not predict actual performance levels for traits: they predict differences in performance levels of individuals as parents. For example, if bull A has a weaning weight (WW) EPD of 20 pounds and bull B has one of 5 pounds, we would expect an average 20-pound WW advantage for a large group of calves sired by bull A compared to bull B.

Few if any breeds' average EPDs equal zero. Therefore, before meaningful comparisons can be made, you must know the current breed's EPD averages (table 1). Breed average EPDs are available in breed sire summaries, most of which are available on the Internet or free of charge from the respective breed association. Never compare EPDs across breeds.

All EPDs have an associated accuracy value that measures their reliability. Highly accurate EPDs (> 0.70) are very reliable. On the other hand, the average progeny performance of an individual with low accuracy values may be different from what his EPDs suggest. Most bulls are purchased when young and have had no progeny. The accuracy value on these young bulls is typically low, indicating that some performance variation from the published EPD is likely to occur in their offspring. Also, the low accuracy suggests that the young bull's EPD values may change as progeny data are collected. Nevertheless, EPDs on young bulls provide offspring performance insight that can't be obtained elsewhere.

Performance
There are several bull test stations at which performance tested bulls are available. Operators at these stations compare individual performance of potential herd sires by feeding large numbers of similar age bulls at a single location, allowing meaningful comparisons to be made between individual bulls. Typically, two or more ratios are combined, resulting in a composite index that is usually specific to that particular test station. Traits typically used in the test station indices include test average daily gain, adjusted yearling weight, and weight per day of age. Other traits may be included, depending upon specific breed or test station guidelines. Remember to compare ratios or indices only between bulls from a specific test. No comparisons can be made between tests starting at different times or between different test stations.

Putting it all together
Each of the aforementioned characteristics should be considered a tool. Just as it takes multiple tools to build a house, so also it takes a variety of tools to identify the "right" bull for a herd. If you are considering a bull from a production sale or a performance test sale, request the sale catalog early, study the published performance information (EPDs and individual), and critique the different pedigrees available. Make your initial choices based upon the information you have available before arriving at the sale site. Once at the site, critique the phenotype and disposition of each of the bulls you selected. If the physical characteristics are acceptable, select the bull as a candidate for purchase.

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