Expected progeny differences (EPDs), generated through our World Angus Evaluation genetic evaluations, are predicted breeding values that allow for fair comparison of animals across herds, regardless of environment and management differences. They are expectations of how an animal’s progeny will perform, on average, for specific economically relevant traits.
Expected Progeny Differences (EPDs) are the most powerful genetic tool we have for selecting the best animals for your breeding program.
EPDs are values that predict how the future progeny of an animal will perform relative to the progeny of other animals in the same breed. They are expressed in the units of that particular trait. For example, weaning weight is measured in pounds thus the Weaning Weight EPD is expressed in pounds. Another way to look at it is EPDs measure an animal’s value as a parent.
EPDs are based on pedigree information and performance data such as weight information and are then compared to other animals within a contemporary group. The different traits are adjusted to a standard age to ensure that all animals are equal when they are compared.
Introducing the New Functional Longevity Genetic Evaluation (FL EPD) released on June 6, 2025
Cow longevity, fertility, and productivity are critical factors towards profitable and sustainable beef production. Your Canadian Angus Association, in partnership with the American Angus Association, have worked with Angus Genetics Inc. (AGI) to develop a genetic evaluation that describes the probability of a sire’s daughters staying in the herd and producing a calf every year. The trait, Functional Longevity (because longevity is meaningless unless there a calf associated with staying in the herd), is an advancement on previous stayability models where females were only assessed as to whether they stayed in the herd. The development of the genetic evaluation for Functional Longevity (FL) was based on whole herd reporting data, which Canadian Angus members have painstakingly provided for decades. Complete herd inventory submissions were critical towards the successful development of this genetic evaluation.
As a result of these records, we are able to provide Canadian Angus members with some preliminary results from our research genetic evaluation for Functional Longevity (FL EPDs). FL EPDs predict the number of calves a sire’s daughter is expected to produce by 6 years of age compared to other sires’ daughters in the population.
The unit of the FL EPD is the number of calves produced by 6 years of age. A higher EPD means that on average, a sire’s daughters are predicted to produce more calves by 6 years of age compared to a lower EPD.
For example, if Sire A has an FL EPD of 1.5 and Sire B has an FL EPD of 0.5, on average, the daughters of Sire A are expected to produce one more calf by age 6 compared to Sire B’s daughters.
The trait is lowly heritable at 0.09 or 9% meaning that 9% of the variation we see in cows staying and producing in herds at 6 years of age is due to genetics.
EPDs are useful tools when planning breeding programs.
Attention should be paid to the heritability—the proportion of variation for a particular trait that is determined genetically—and correlations to the traits a breeder wants to improve upon within the herd. Some traits are more heritable than others resulting in faster progress being made in comparison to other less heritable traits. Also, many traits are correlated, wherein the trait is affected by the expression of several other traits. It is important to be aware of such logistics when developing selection criteria in a breeding program.
The higher the heritability of a trait, the more accurately an individual’s own performance will predict its breeding value for this trait. Calving Ease and Milk have lower heritability. This means that there are a lot of factors in addition to genetics that influence these traits, and a cow’s own milking ability does not reflect her daughters’ milking ability to a high degree. Conversely, growth traits are moderately heritable and carcass traits are highly heritable.
EPDs are useful tools when planning breeding programs. Attention should be paid to the heritability and correlations to the traits a breeder wants to improve upon within the herd. Some traits are more heritable than others resulting in faster progress being made in comparison to other less heritable traits. Also, many traits are correlated, wherein the trait is affected by the expression of several other traits. It is important to be aware of such logistics when developing selection criteria in a breeding program.
Understanding the heritability and the effects of correlation between traits will aid in developing a genetic selection program that will optimize improvement on desired traits while minimizing undesirable side effects.
Each individual breeder must set his own selection goals based on the needs of his operation, the situation for that trait in his herd, and his production environment.
Possible Change Table
This table provides EPDs users an estimate of how much an EPD could change based on its accuracy. An YW EPD with a 10% accuracy may change +/- 23 lb as more information on the animal becomes available. In comparison, a YW EPD with a 90% accuracy is within +/- 2.6lb of the animal’s true breeding value for YW. It is possible to calculate more accurate EPDs when there is more performance, pedigree, progeny and genomic information available on an animal. The higher the EPD accuracy, the more confidence the producer can have in it.
Commercial buyers rely on EPDs to make their purchasing decisions
Producers that do not have EPDs for their animals often lose out on selling their animals because of this. Buying an animal with EPDs provides a genetic snapshot of an animal’s breeding potential. While appearance and pedigree should be considered, EPDs allow a fair comparison of breeding value by removing environmental bias such as climate, feed and special management.
EPD Accuracy
Canadian Angus Association provides breeders who participate in the Performance Program with two levels of EPDs:
Parental Average EPDs: These are the most basic and least accurate EPDs. They are the best guideline available when calves are first reported and there is no performance data on them yet. Parental Average EPDs are indicated by a P for accuracy and are simply an average of the dam and sire’s EPDs.
World Angus Evaluation EPDs: The World Angus Evaluation for all Canadian Angus cattle (Black and Red Angus), American and Australian Angus cattle, was launched in October 2023. There are many advantages to the World Angus Evaluation, including the combined Canadian Angus, American Angus, and Australian Angus data which gives us the ability to calculate more accurate EPDs. Together, the Canadian Angus Association, American Angus Association and Angus Australia genetic evaluation includes more than a million animals that have been genomically tested. The World Angus Evaluation has also allowed us to expand your genetic evaluation and bring you EPDs for new traits that we believe are priorities for the industry, and economically relevant to you.
Example of EPD Use
To use EPDs effectively you must understand how they work.
Imagine you are interested in purchasing a couple of bulls for your herd.
You are looking at the EPDs in a sale catalogue. Bull A has a weaning weight EPD of +10 and Bull B has a weaning weight of +60. What does that mean? How can you use the EPDs to choose between the two bulls?
If these animals were randomly mated with 10 similar cows, we would expect the group average weaning weight of Bull A’s offspring to be 50 lbs lighter than that of Bull B’s (60-10=50).
Sire Selection
It would be easier if we could assume that the highest EPDs are the best. Unfortunately, it isn’t that simple. Like most decisions, using EPDs for sire selection involves trade-offs. For example, bulls with high growth EPDs may sire calves with a higher birth weight as well. And there may be other impacts on your operation to consider.
World Angus Evaluation Genetic Evaluation
Calculate More Accurate EPDs
The World Angus Evaluation for all Canadian Angus cattle (Black and Red Angus), American and Australian Angus cattle, was launched in October 2023. There are many advantages to the World Angus Evaluation, including the combined Canadian Angus, American Angus, and Australian Angus data which gives us the ability to calculate more accurate EPDs. Together, the Canadian Angus Association, American Angus Association and Angus Australia genetic evaluation includes more than million animals that have been genomically tested. The World Angus Evaluation has also allowed us to expand your genetic evaluation and bring you EPDs for new traits that we believe are priorities for the industry, and economically relevant to you. These traits include Teat Score, Udder Score, and Functional Longevity.
These traits include:
Using EPDs for Bull Selection
EPDs are a genetic selection tool that some producers appreciate and use to select their bulls.
EPDs are calculated using pedigree, performance and genomic data. Canadian Angus members participate in the voluntary Performance Program through which they collect and submit performance data on fertility, calving ease, growth, structure, carcass quality, and feed efficiency for their calves. A big thank you to all our members who take the time to measure and record this data; without you we cannot generate the genetic selection tools that we do.
Many members have started measuring and submitting phenotypes for the new traits introduced here. As you start calving, please do not forget to record teat and udder scores on your cows.