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Extension by Scott Lake

by Wyoming Livestock Roundup

Selecting the Right Bulls for Your Cows
By Scott Lake, UW Extension Livestock Specialist

It’s that time of year when your mailbox is full of sale catalogs and AI books. It’s bull season! During the next few months, there will be a bull sale just about every weekend somewhere nearby. Decisions made during the next few months about what types of sire bulls or AI bulls to purchase can have a dramatic impact on your operation’s profitability for years to come. So, where do you start?
    First, it’s important to understand the impact that bulls have on a herd’s genetic makeup. The simple question is: how much of any given calf’s genetics are from the bull? Obviously, the sire and dam each provide 50 percent of a calf’s genetics. However, half of the dam’s contribution came from her sire and a fourth comes from her dam’s sire, resulting in 87.5 percent of the calf’s genetic makeup being derived from three bulls.
    The lingering effect of a bull’s genetics within a herd underscores the importance of making sound selection decisions. Below are a few guidelines to possibly help with the selection process.  
Set Herd Goals
    A good breeding plan is not only useful, but is also extremely important toward maintaining long- and short-term goals. It is important to have a plan of what type of cattle you want to produce. In considering this, it is important to develop cattle that will maximize the production potential on your ranch. What kind of resources does your ranch have? How much energy or protein supplementation are required? What type of conditions and terrain do your cows need to be able to survive? These are all questions to consider when developing a long-term breeding plan.  
    Another important question to ask is: how does crossbreeding fit into the breeding plan? Commercial cow/calf producers who do not utilize a good crossbreeding program leave a tremendous amount of production potential, and dollars, on the table. Crossbred steer calves are heavier at weaning and replacement heifers reach puberty earlier and at a lighter body weight and have greater longevity. Quite simply, crossbreeding is one of the easiest ways to increase profitability on the ranch.
    Once a plan is in place, stick with it. It’s important to work toward a genetic and production goal, and not change directions with every hot new trend that comes along.  
    What traits should be emphasized during the selection process? This is a very common question, and it’s not easily answered.
    Every year it seems as though new EPD values are available to aid in the selection process. There is more information available on individual bulls and pedigrees than at any other time in history. At the very least, information is available to make an informed decision about the bulls that are ultimately selected.
    A couple important questions should be answered to identify which traits are the most important to your operation. First, do the traits that you currently use for your selection criteria contribute to increasing profitability or reduce costs of production? If you have repeat buyers of your calves, or market them in a branded program, are the traits that you are selecting for your herd bulls important to the success and profitability of your customers?
Structural Soundness
    No matter how genetically superior a bull is in any economically important trait, he should only be considered as a herd bull if he is structurally sound and physically fit enough to seek out cows in heat and breed them.
    One of the problems faced with evaluating structural soundness is that it is not an all-or-nothing proposition. Very, very few animals have no structure defects. The key is to select animals with minimal defects that have little impact on his or future replacement performance. Generally speaking, it is probably best to evaluate structural soundness of bulls from the ground up, keying on the bull’s feet, toes, pasterns, knees, hocks, sheath and testicles. The bull should be able to move freely and strike the ground evenly with each step.
    No matter how good a bull looks in the pen or on paper, if he is not fertile he will not do your operation any good. It is important to have a breeding soundness exam performed on bulls. This is a good recommendation for current bulls that are returning to the herd, as well. This is a small investment to assure a successful breeding season.  
    Scrotal circumference is an important indicator of not only his volume of semen and percentage of normal semen, but it also has an impact on attainment of puberty in replacement heifers. There is evidence to suggest that the earlier a heifer reaches puberty, the shorter the post-partum interval (period of time between calving and when she starts cycling again) she will have after calving. Therefore, selecting bulls with adequate scrotal circumference is extremely important. As a general rule, yearling bulls that are considered should have a scrotal circumference of 30 centimeters by one year of age.  
Trait Selection
    Individual traits of importance need to go hand in hand with the breeding plan and long-term goals. Producers with different resources and marketing strategies may place emphasis on different traits. For example, calving ease is a trait most producers are concerned about, however, producers with very limited labor during calving may rank calving ease as their most important trait. Likewise, some producers may retain ownership and market their cattle on a grid to take advantage of their genetics and the potential to receive premiums. These producers will place a higher value on growth potential and carcass traits than perhaps a producer that would sell calves at weaning.  
    However, it should also be kept in mind that single trait selection or “chasing” certain traits can have disastrous effects on reproductive performance, carcass quality and the longevity of cows with the herd. No single trait should be the lone selection criteria, rather it should be considered along with other traits to fit within the parameters of your long-term goals.  
    The bottom line for producers should be profitability. Research has shown over and over again that reproduction is the single most important factor for the economic success of the cow/calf producer. Therefore, I will always recommend that the focus of a producer’s long-term goal and bull selection criteria should be on developing sound females that will reproduce on a yearly basis and remain in the herd for a long period of time.  
    For more information, contact Scott Lake at 307-766-3892 or

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