Selecting the Herd Sire

 By Jaclyn Krymowski for American Cattlemen

 The sire is the single most influential individual in the herd. “(What) we think about when we change a cattle herd…we’re very focused on females but we all realize it’s the bulls we buy that make the change,” says Dr. Dan of Angus Genetics Inc. in a seminar titled “Selecting bulls for the beef herd.”  Unlike several factors impacting production and management, genetic influence is permanent. This is especially true for operations that retain replacement heifers.

 The inputs from a single bull, for better or for worse, will impact many generations down the line. That’s a lot of pressure on a single animal; the selection task can seem daunting. Narrowing in on the right criteria can make the decision easier.

Know your needs
 Things such as region or climate, economy, consumer demand and even labor can all have varying weights of importance that may influence genetic criteria. Harsh climates may demand more traits directed at survivability or maternal capabilities. Operations chasing high premiums may find the need to increase marbling or yield grades. The list of possibilities and scenarios are endless. Whatever the situation may be herd goals should remain consistent, mindful that they are only achievable over a period of time. The last two or three sire generations used is where you’ll be able to see the change, notes Moser.

 The payout for bulls makes a big difference on the bottom line. This is where knowing your market and what traits your specific operation needs to profit is so important. Moser used cow-calf producers selling at weaning weight as an example. Say two different bulls sire 20 calves each, with one averaging 570lb calves at weaning and the other only 550lb calves. After only 4 years of selling those calves at a liveweight of $1.80/lb. will equate to a total of $2880 difference between them.

Know your tools
 Hand selecting individual traits to improve a herd would be an impossible task. Breed associations make this feasible in the forms of EPDs, dollar indexes, and most recently genomic data. The traditional EPD pulls data from the pedigree, performance, and recorded progeny into one number. “It’s really not a magic formula, it’s just very simple statistics that are used to come up with a prediction,” says Moser. EPDs only account for the outputs that create revenue. Dollar indexes have the advantage because include both the outputs and the expense of inputs, for a more accurate prediction of an animal’s expected value. 

 The adoption of genomics is making young sires a more attractive option for cattlemen who want to be on the cutting edge of genetic advancements. Previously, young sires were always a higher risk because they lacked their own progeny data. The accuracy of tested animals is already very high and continues to improve, meaning these animals with no progeny can be purchased with confidence. Genomic testing may not be an option for every single bull considered for purchase. In this case, the risk is always minimized the more proven data a bull has. In the case of untested bulls, especially for the very young, EPDs are still the best go-to option. “Even a low accuracy EPD on a yearling bull is better than any other information that you could have,” says Moser. 

Fertility
 A bull’s pedigree is only as good as his ability to get cows pregnant. Besides the obvious need for soundness of the individual animal, the bull’s reproductive capabilities can be his limiting factor. The average number of cows a bull can be expected to cover is typically about 25-30, per the industry standard. An experienced bull of optimal health and soundness can breed as many as 50 or more animals, according to some studies. However, there is no one indicator that can guarantee an individual’s fertility. A breeding soundness exam can provide a good idea of how a particular bull will perform each given year. The scrotal circumference measure offers the highest correlation to sperm production in yearling bulls. A threshold of at least 30 cm is seen as a rule of thumb, but studies have shown variance between breeds, environment, and age in months. If possible, sperm motility and shape should also be evaluated as part of the exam. Research shows for optimal fertility, samples have a 50% motility rate and with 70% or more normal sperm.