Genetic Evaluations
Wagyu National Cattle Evaluation
The Wagyu National Cattle Evaluation (NCE) compiles the data collected and reported by Wagyu breeders, as well as the more recently collected genomic results, into the best possible predictions of each animal’s genetic merit.
Since the early 1980s, Expected Progeny Differences (EPD) have proven to be effective as a selection tool for making directional change in herd performance for those traits which EPD are computed and published.
Genetic evaluations estimate the portion of genetic potential an animal passes down for various traits through statistical analysis. An EPD is an estimation of how future progeny of an animal are expected to perform relative to the population used in analysis. EPDs are especially effective for comparing cattle across herds and years (even within the same herd), a task not possible with phenotypes alone. Recent advancements in genomic technology have enhanced the accuracy of genetic predictions resulting in a breeder’s ability to make more accurate selection decisions. It’s important to know that EPDs are only comparable within the population the EPD were computed.
Genomic Enhanced Evaluation
Genomic results are incorporated into the Wagyu genetic evaluation using the Single Step method. Single Step is the most accurate and reliable tool for estimating genetic values of animals. Incorporating genomic data into the genetic evaluation results in greater accuracy, especially for younger animals or animals with no or fewer progeny.
How to Read EPD Information
Helpful information for every animal is available on the EPD detail screen. The EPD is listed across the page for birth weight, weaning weight, yearling weight, maternal milk, total maternal, carcass weight, ribeye area, fat thickness, and intramuscular fat index.
- EPD: An estimation of how future progeny of an animal are expected to perform in a particular trait relative to other animals in the same analysis.
- +/- Chg: This is the possible change value. Please see the discussion on accuracy for more information.
- ACC: Accuracy, an indication of how close genetic estimates are to an animals true genetic breeding value as a parent.
- % Rank: Percentile rank of the Animal compared to the other animals in the evaluation.
- Prog/CG: The number of progeny meeting all edits and used in the genetic evaluation and the number of contemporary groups those animals are represented in. For Maternal Milk this number reflects the number of daughters in production (i.e. daughters that produced progeny meeting all edits and used in the genetic evaluation) and the number of contemporary groups those progeny were represented in.
EPD Traits Reported
The expected difference in average birth weight (pounds) of progeny. Birth weight reflects prenatal growth.
The expected difference in average weaning weight of calves. The evaluation reflects the genetic influence on pre-weaning growth rate.
The expected difference in average yearling weight of progeny. The evaluation reflects genetic influence on both pre-weaning and post-weaning growth rate.
The genetic ability of a sire’s or dam’s daughters to express in pounds of weaning weight in her calves due to her maternal ability through mothering instinct and milk.
A value to predict the weaning weight performance of calves from an animal’s daughters due to genetics for growth and maternal ability. Total Maternal is calculated by adding ½ the Weaning Weight EPD to the Maternal Weaning Weight EPD.
This weight expressed in pounds is a predictor of the differences in hot carcass weight of a sire's progeny compared to progeny of other sires.
Ribeye Area expressed in square inches and measured at the 12th and 13th rib interface which estimates the possibility of the size of ribeye yielded in a carcass.
Rib Fat expressed in inches and measured at the 12th
and 13th rib interface, is a predictor of the differences in external fat thickness that is traditionally discarded
An animal’s expression of fat in the muscle, also known as marbling, measured within the ribeye at the 12th and 13th rib interface.
Search Wagyu EPDs
Search through our database in DigitalBeef to explore animal's EPD values.
Heritability
Heritability indicates what proportion of the total phenotypic variation is due to genetic variation among individuals. Heritability is a calculated as a percent of phenotypic variation that can be attributed to genetics. The remaining observed variation is due to environmental influences.
Traits with low heritability estimates are influenced more by environment than by genetics, thus genetic progress from selection may be slow. Traits with low heritability respond greater to the effects of crossbreeding. Since heritability is already an integral part of the EPD calculation, EPD reflect actual differences and require no adjustment.
Accuracy
Accuracy is an indication of how close genetic estimates are to an animal’s true genetic breeding value. Accuracy values are useful to breeders to determine the reliability of an EPD. Accuracy values range from 0.0 to 0.99, depending on the amount and quality of information that is known about an animal for any one of the reported traits. As the amount of information increases, the accuracy for that trait increases accordingly.
Click here for the "possible change" table (standard error of prediction) for various levels of accuracy for the traits reported. You will notice that as the accuracy level increases, the possible change value decreases. Still, an EPD can change from year to year even though it may have a high level of accuracy. The point to remember is that the possible change of an EPD with a high ACC is correspondingly less than those of an EPD with a lower ACC value.
Possible Change
is expressed as "+" or "-" value and can be described as an estimation of the potential change (in trait units) for a given EPD. The true genetic value of each genetic prediction would be expected to fall within (plus or minus) one standard deviation 2/3 of the time. This confidence range depends on the standard error of
prediction for an EPD.
Percentile Rank
You may ask the question, how does my animal rank when compared to the rest of the Wagyu population?
Ranking of an EPD in the breed is another useful tool for Wagyu breeders. The percentile rank tables
available for sires, dams, and non-parent animals are an
often-overlooked resource when making genetic selections.
If an active sire’s Milk EPD is equal to +2 lb., then by locating that
EPD in the table for active sires and associating it with the percentile
in the first column, the relative ranking to all active sires in the
population can be assessed. These percentile rank tables also provide tables for ranking of Fullblood animals.
Rules for Publication of EPD
All registered animals in all herds will have reported EPDs that follow these guidelines. Find our rules for EPD publication here.
Overview of Rules for Publication of EPDs
- EPDs are published for animals with a minimum of a qualifying weaning weight submitted.“Qualifying” defined as reported weaning weight was used in genetic evaluation. (Accuracy will be reported as a numeric value).
- Pedigree Estimate EPDs (PE EPD) are computed only if the Sire and Maternal Grand Sire (MGS) have EPDs with an accuracy value. We don’t compute PE EPD if the Sire and/or MGS has a PE EPD or no EPD. In other words, we don’t use PE EPD to compute PE EPD. (Accuracy will be reported as P).
- EPDs will be published for animals with a genotype included in the evaluation that meets minimum imputation standards.
- EPDs will be published for ancestors (parents, grandparents, etc.) of descendants that have weaning records included in the genetic evaluation.
- EPDs will only be published for animals that are registered with the American Wagyu Association.
Guidelines for Collecting and Reporting Performance Data
Without performance data, corresponding Expected Progeny Differences (EPD) cannot be computed. Refer to the Performance Guidelines for proper date collection procedures to follow for Wagyu.