New & improved genetic predictions

News
Feb 3, 2012
by WLJ
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EPDs predict differences in progeny performance, and are calculated from comparisons within Contemporary Groups. (A group of calves that were born in the same year, calving season, herd, and are of the same sex and were fed and managed alike.)

EPDs have a clear advantage over less sophisticated predictors such as actual weights or withinherd ratios.

Actual and adjusted weights are affected by environment, nutrition and management. Contemporary group ratios are an improvement, as they account for these environmental variables. However, they do not incorporate comparative performance data on related individuals in countless herds throughout the country. Red Angus EPDs account for these sources of variation in performance as well as mating bias (which cows were bred to which bulls). The power of these genetic predictions is multiplied by including every contemporary group from herds in the entire Red Angus breed.

Multi-Breed EPD Revelation – made possible through collaboration with American Simmental Association. This advancement incorporates a true multi-breed EPD model which accurately accounts for variation in animal performance due to heterosis, as well as accurately accounting for additive genetic differences between breeds. This enhancement enables Red Angus to provide reliable EPDs on all animals in the database, regardless of breed composition.

Understanding ACCURACY: Red Angus EPDs are often presented with a corresponding accuracy value, which measures the strength of the relationship between the genetic prediction (EPD) and true genetic value. Accuracies are reported as a decimal number from zero to one. As accuracy value approaches 1.0, the EPD is “accurately” or closely estimating the true genetic merit of an animal for a given trait. Although low accuracy EPDs are less reliable when compared to those of proven sires, independent research demonstrates EPDs to be the most meaningful indicator of animals’ true genetic merit. While “perfect” accuracies of 1.0, are never achieved, many heavily used Red Angus sires have accuracies greater than 0.9 (some as high as .99).

Absolute performance is not predictable... Relative performance is. For Example: Suppose your old herd bull has a yearling weight EPD of 50. You buy a new bull with a yearling weight EPD of 70. How much will the new bull boost your calves’ yearling weights?

We cannot predict how much performance will change from one year to the next because of varying environmental conditions (rainfall, temperature, available feedstuffs, etc). However, we do know this: the calves raised in the same contemporary group sired by your new bull will have the genetics to weigh an average of 20 pounds more at 365 days Bull selection simplified Follow these simple steps to match bull power to your program’s goals.

1) Know your target markets: feeder calves, yearlings, value based grids, replacement females.

2) Have a true appraisal of how close your cow herd is to those targets; always understanding your cows have to continue to live and reproduce in your environment.

3) Identify bulls whose EPDs predict the ability to move your cow herd in the right direction for the traits required to hit your market endpoint.

What is your breeding objective?

1. Building a cow herd?

• Combine low expense traits (ME EPD) with acceptable revenue traits to breed efficiency into the cow herd.

• Improve fertility with selection pressure on HPG EPDs. • Sleep through the night by selecting high CEM EPDs. Improve longevity and lower replacement rates by selecting higher than average STAY EPDs.

2. Breeding virgin heifers?

• Select for CED EPD as the most meaningful predictor of calving ease. Red Angus’ CED combines birthweight and other factors affecting calving ease scores.

3. Selling calves or yearlings?

• Heavier payweights may be achieved by selecting higher WW EPDs, but... make sure heavier is what you want. Heavier weaning weights mean heavier payweights for calf feds. However, for those who background their calves, too much weaning weight could translate into yearlings that are too heavy when they enter the feed yard, and finish too heavy. Overshooting performance goals can be just as detrimental as falling short.

Enhance your reputation and improve traits that impact feeder profits, such as carcass traits and postweaning gain (YW).

4. Retaining Ownership?

• Docile and fast starting, Red Angus are easy to start on feed and keep on feed.

•Balance YW EPD of potential bulls with the existing cow herd to pinpoint needed improvement for post weaning gains.

• Increase payweight with selection for improved CW EPD.

5. Selling on a Grid?

• Fine-tune marbling (MARB), rib eye area (REA), and back fat (FAT) EPDs to target value based grids.

• Target YG 1 & 2 premiums and avoid YG 4 discounts by applying selection pressure on YG EPD.

• Optimize carcass weights to increase payweights while avoiding discounts for heavy weight carcasses.

•Balance Carcass EPDs against existing cow herd genetics:

1. Cowherds of higher continental influence may require additional selection pressure on marbling EPD to improve quality grade.

2. High percentage British cowherds typically benefit from selection pressure to reduce YG and increase CW.

Red Angus Association of America

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