Here are some selection tools to help you make decisions on the next generation of cattle you raise.
By: Adam Hady, University of Wisconsin Extension
With beef prices high and the calf crop in, beef producers are starting to decide which of this year’s heifers and/or bulls they are going to keep back for next year. Beef producers have a whole host of tools to help them decide. Here are four ways producers can use to select the traits that they want in their next generation.
To start with, let’s consider visual appraisal. This is the eye test. Utilizing this method of selection is based on the phenotype, or the looks, of the animal. For trait selection, if the traits are highly heritable, this can be a good method, however it may not be the best method for genetic progress. One of the negatives of visual appraisal is that we can often miss out on a stronger performing animal due to the simple fact of age and eye appeal. Visual appeal is beneficial for helping select and or cull for physical traits that could be problematic long term like feet and leg and other structural traits.
Another process is production testing. Production testing allows producers to make selection decisions based on what the animal has actually done when compared to its contemporaries. In this system records are kept on animal performance. The records are then standardized or adjusted for known environmental factors that influence the performance in an attempt to put all individuals in a herd on an equal basis. For example, let’s look at the adjusted weaning weight formula: Average Daily Gain X 205 days (Standards Days to Weaning) Birth weight Dam Adjustment Factor= Adjusted Weaning Weight
Let’s compare at two calves:
Calf A: heifer calf that was born on 4-19 (70 lbs. BW) to a two year old cow weaned on 10-5 with a weight of 440 pounds
Calf B: bull calf that was born on 4-6 (85 lbs. BW) to a five year old cow weaned on 10-5 with a weight of 520 pounds.
Based on visual appraisal, on the day of weaning, we would say that the bull calf was a better calf and higher performing than the heifer calf. The reality is that when using the numbers provided and the dam adjustments the two calves have the exact same adjusted weaning weight and we can fairly judge the production of the animal by making the correct adjustments for sex of the calf, maturity level of the cow, and her ability to milk.
Calf A: 1.85 ADG x 205 Days 70 BW 54 DAF =503 pounds adjusted weaning weight
Calf B: 2.04 ADG X 205 Days 85 BW 0 DAF = 503 pounds adjusted weaning weight
The third tool we have for selection is progeny testing. Progeny testing allows us to select animals based off the performance of their offspring. When using progeny test we use what is called Expected Progeny Difference (EPD). These are the genetic predictions of an individual and are deviations from a base set by the breeds. These predictions are set based on pedigree information and have low accuracy levels until the animal has progeny of their own. In both of these last two tools; neither takes into account the looks (structural correctness) of the animal just the data associated with the animal.
A fourth method to consider adding to our toolbox is marker-assisted selection. This method allows for us to utilize DNA markers that have a measurable effect on a complex trait. This allows us to make selections based on these markers that we would otherwise have to wait until we had higher accuracies in EPD’s to evaluate. Examples would be markers associated with tenderness and marbling. These tools help add information and value when marketing our calf crop.
So using a combination of these selection methods can be useful while building and maintaining our herd. Using the tools in the toolbox will help us to keep back the animals most likely to keep our genetic progress moving forward.
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