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Northwest Iowa Dairy Outlooks

A local discussion of current science and issues concerning dairying in northwest iowa

Megan Rolf, Oklahoma State University, gave producers who attended the Cattle Trails Cow/Calf Conference a great over-view of how to select bulls that can make an economic impact on their cow herd.

Rolf started by explaining expected progeny differences.  Better known as EPDs, she noted that have been used in the beef industry since the 1970s. EPDs describe exactly what their name implies: The differences which are expected to be see between progeny of two different animals.

If a herd owner is considering using two potential herd sires, he is going to be interested in the difference between their EPDs rather than the actual EPD value itself.

Keep in mind that comparisons between EPDs of two different sires are only valid between bulls of the same breed. For example, you cannot compare a Simmental with an Angus bull and get a valid comparison.

Each breed association will have its breed average EPDs for spring 2013 available on its website or through its breed representatives. A listing of the breed average EPDs for 17 breeds reported by the U.S. Department of Agriculture is available at

Simply mating to animals with the largest or highest ranking EPDs is not always the best strategy for genetic improvement. It is important to consider the resources (labor, forage, feed, etc.) available to you and to select bulls and females that will generate optimum performance (not maximum!) given the resources available in your production environment.

All EPDs have an associated accuracy value listed with the EPD. The accuracy value reflects the confidence in the EPD prediction and will be reflected as a number between 0 and 1. Zero means that there is no confidence in the EPD prediction while a 1 would mean complete confidence in the EPD prediction. Generally, EPDs on yearling bulls will be low (between 0.05 and 0.35) and will increase over time if performance records for the bull’s progeny are reported to the corresponding breed association.

Commonly used AI bulls will often have EPD accuracies that exceed 0.8 and are considered proven sires because the recorded evidence gives us a high degree of confidence in the EPD prediction. However, even low accuracy EPDs provide a more direct route to select for the animal’s genetic merit than just evaluating these traits by sight (phenotype). Visual evaluation of an animal’s phenotype should only be used in cases where there are no EPD predictions for the trait (soundness and movement, for example). Using high accuracy bulls in an AI program can help to manage risk at breeding time by allowing the breeder to choose bulls that possess the characteristics they desire.

It is important to identify those EPDs that are important to your production system and to select using only those metrics. For example, identify important output traits (such as weaning weight) and traits limiting in the environment (like milk production) and then choose the EPDs that best fit those parameters and select only on those EPDs.

It is important to monitor your genetic progress by recording performance data for the offspring you produce. For commercial producers, it is not important to record as much data as should be expected from a seedstock enterprise, but it is still a good idea to collect calving ease data (assisted vs. unassisted), relevant output data (weaning weights, if selling at weaning), and cowherd data (mature weight, etc.).

“Once you have accumulated a group of animals that fit your environment and available resources well, sometimes the best genetic change is no genetic change,” says Rolf.

Local Ag Economist Stan Bevers notes that the decision to purchase a herd bull relates to an investment that is expected to pay out over a productive life ranging from 3 to 5 years. While the bull purchase price may seem expensive, the investment in a higher priced bull can contribute to improved production of market-preferred calves and better weaning weights. Thus the investment may be justified, particularly when viewed in relation to the number of calves the bull can sire over his useful life.

In many cases, the salvage value (the net sales value when the bull is culled) helps offset a substantial portion of bull purchase cost, which reduces the total depreciation cost of a bull. With ownership costs (depreciation, death loss and interest cost) prorated over the number of females serviced and calves produced during the bull’s productive life, a decision-maker can approach the potential investment on a sound basis.

A spreadsheet decision tool is available to help producers put the cost of maintaining a bull into proper perspective with respect to both cost and production at

The usefulness of this tool is its capability to quickly evaluate the impact on the cost of a bull by changing different variables of interest including the bull’s purchase cost, estimated salvage value, and expected economic life and interest rate to be used in calculating the cost of capital used in the bull investment. These values are used to calculate the ownership costs, which become fixed costs once the bull is purchased.

To evaluate the impact of changes in the number of cows serviced by the bull annually, a sensitivity table is included. The bull cost per cow is quite sensitive to the number of cows serviced, which reinforces the importance of matching herd size to bull capacity.

A local opportunity to purchase a quality bull will be on Wednesday, March 6 during the live production bull sale at the Wichita Falls Ranch and Farm Expo. The production bull sale will start at 6 p.m. and will feature 60 high quality bulls.

The sale management will have the available genetic information and photos on the event website and a buyers’ reception is planned at 5 p.m. before the sale.


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