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.
Choosing the right traits:
205 days of age
for weaning weight
365 days of age
for yearling weight
365 days of age
for bulls in ultrasound
390 days of age
for heifers in ultrasound
EPDs are then calculated using complex statistical procedures monthly during the National Cattle Evaluation (NCE).
EPDs are then calculated using complex statistical procedures monthly during the National Cattle Evaluation (NCE).
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.
We also participate in BOLT genetic evaluations with our long standing partner for Red Angus evaluations, the Red Angus Association of America. BOLT is ran by the IGS group and the American Simmental Association. The IGS group includes American and Canadian Simmental, Gelbvieh, Shorthorn, Limousin, Shorthorn, Red Angus and several other partners. The beef improvement federation (BIF) publishes across breed adjustment factors to help members estimate what their AngusONE EPDs would convert to in another genetic evaluation.
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.
Depending on your target market, you can improve your herd by selecting for the right traits. Choosing a bull with high growth EPDs, in particular, the weaning weight EPD, means more pounds at sale time. Looking at the EPDs of a prospective bull is essentially just as important as looking at specifications of an engine when buying farm machinery or vehicles.
To evaluate seedstock, use a combination of EPDs, pedigree and visual assessment. With EPDs, the concept of “intermediate optimums” works best.
Selection for one trait or for extremes generally results in unexpected consequences due to genetic correlation. For example, intense selection for high yearling weight will also increase birth weight. Successful cattle breeding requires a thoughtful and balanced approach to optimize fertility, growth and carcass merit while improving profitability and efficiency. EPDs are the best tool we currently have to compare animals between herds and countries.
The quality of your EPDs also reflects the quality of data that comes into the office. Taking pride in your paperwork increases error-free data entry. Submitting your data on time or early eliminates the chances of receiving a Missing Data Report and your animals subsequently not getting EPDs due to non-compliance.
To ensure that your animals receive EPDs you must:
- Enroll in the Performance Program
- Submit weaning weights on all of your animals
- Ensure your animals are within the acceptable age ranges: 120–280 days for weaning weights (WW) and 290–440 days for yearling weights (YW) for all Angus animals
- Animals that are in a management group of their own, such as twins, fosters, ET calves and lone bull calves are automatically placed into a single animal contemporary group and will not receive EPDs until they are parents to performance-recorded progeny or genotyped.
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).
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.
It should also be kept in mind that reaction to selection can differ from trait to trait. This is because some traits have higher heritability than others, and are more easily passed to offspring. For instance growth traits such as weaning weight respond faster to selection than reproductive traits such as age at first calving.
A balance of traits is required, and the perfect balance for you will depend on your climate, nutritional and economic environment, as well as the management goals you have set for your herd.
One way to select for several traits is to set minimum and maximum acceptable levels for each trait, and then choose sires that meet the criteria. Another method would be to rank all sires on each trait, then develop a weighted index which ranks each bull from one (most desirable) to five (least desirable) for each trait. The bull with the lowest total score would be your first choice.
A Sample Sire Evaluation
|Bull||Birth Weight||Weaning Weight||Yearling Weight||Milk|
Producer 1 is looking for a sire that can be used on heifers; he wants a bull that will produce low birth weights and he wants to keep some heifer calves as replacements. Growth performance is not his first priority. The sire that fits his needs is sire D. He has a low birth weight EPD and above-average milk EPD.
Producer 2 has a sound breeding program; he is looking for a sire that will maintain performance and milking ability. He will select a bull that will increase growth performance and milk while maintaining calving ease. Sire B is his choice.
Producer 3 has a herd of above-average-frame cows and is not planning on keeping heifers as replacements. She is looking for a bull that will give her the most profit at weaning. Sire A will give her the best result in weaning weight. If heifers are kept as replacements, they will, on average, be inferior for maternal milk.
Producer 4 wants to maintain his calving performance and growth performance but would like to increase the milking ability in his females. Sire C is his choice.
Traditionally, EPDs have been calculated using pedigree and performance information.
The more information that can be included in the calculation of EPDs, the more accurate or reliable the prediction of genetic breeding value will be. Accuracies are always posted with every EPD. P accuracies indicate parental averages. These are a good base line but have the lowest accuracy. P+ accuracies indicate Interim EPDs (Parental Averages plus a small amount of individual performance data). More accurate are national EPDs that have numerical accuracies (1 being the lowest and 100 being the most accurate).
Genomically Enhanced EPDs (GE-EPDs) can have higher accuracies for young animals and animals with limited performance data.
The table below indicates the increase in accuracy you can expect from the genomic marker panel available through the Canadian Angus Association.
|Trait||Correlation (% Genetic Variance)||Progeny Equivalents|
|DMI (RADG)||.73 (53)||17|
These improvements in accuracy are only seen in EPDs with low accuracies. Once an animal has progeny on the ground, and are proven, they have higher accuracy EPDs and the genomic marker panels have less impact on the accuracy of their EPDs. The graph below quantifies the amount of increase in accuracy that can be expected from genomic marker panels for traits that are 40% heritable. Most economically relevant traits in the beef have heritability of 40% or less.
Reporting and Traits: Results from all three panels will be incorporated directly into our genomic evaluation for more accurate EPDs. In addition, the Association will make available percentile rank scores. Below are the traits and the percentile rank information that members will receive.
|Trait||Score 1 – 100|
|Calving Ease Direct||1 = more unassisted|
|Calving Ease Maternal||1 = more unassisted|
|Birth Weight||1 = lighter|
|Weaning Weight||1 = heavier|
|Yearling Weight||1 = heavier|
|Average Daily Gain (Post Weaning)||1 = heavier|
|Milk||1 = more milk|
|Marbling||1 = more marbled|
|Rib Eye Area||1 = bigger|
|Fat||1 = less back fat|
|Carcass Weight||1 = heavier carcass|
|Dry Matter Feed Intake||1 = eats less|
|Residual Feed Intake||1 = lower feed / lb|
|Tenderness||1 = more tender|
|Docility||1 = more docile|
|Yearling Height||1 = more hip height|
|Scrotal Circumference||1 = larger|
|Mature Weight||1 = heavier|
|Mature Height||1 = more height|
AngusONE Genetic Evaluation
Calculate More Accurate EPDs
The AngusONE genetic evaluation for all Canadian Angus cattle, Red or Black, and American Angus cattle, was launched in 2018. There are a lot of advantages to the AngusONE genetic evaluation, including the combined Canadian Angus Association and American Angus Association data which gives us the ability to calculate more accurate EPDs.
Also, together, the Canadian Angus Association and American Angus Association genetic evaluation includes more than half a million animals that have been genomically tested. AngusONE 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.
The world of EPDs is changing and it is important to know what you are looking at and understand how to use it. The multi-step or old way to calculate EPDs has gone to the wayside, with all genetic evaluation service providers adopting a new genetic evaluation methodology called single-step. This methodology includes genomic information directly into the evaluation resulting in more accurate evaluations for all animals included in the dataset.
The Canadian Angus Associations official genetic evaluation, AngusONE, is for both red and black Canadian Angus cattle. The breed averages for this evaluation are shown below. Percentile rank graphs are also provided. These allow you to focus on where an animal is compared to the rest of the population, rather than worrying about the actual EPD number.
Please also take note of the EPD accuracy, which will be listed below the EPD. The accuracy of an EPD depends on the quantity and quality of the information available with which to calculate the EPD. The higher the accuracy of an EPD the more information available and the more reliable that EPD should be.
The possible change table up shows the range of possible change in an EPD based on its accuracy. Animals that have been genotyped (AngusGS tested) have more accurate EPDs. Depending on the trait, genomic information on a young animal can be the equivalent of almost 20 progeny information.
The AngusONE genetic evaluation is done with the American Angus Association. Canadian Angus also participates in the IGS genetic evaluations so that Red Angus Association of America members can invest in excelling Canadian genetics and their cattle will have EPDs at their RAAA Association upon registrations.
Some of these new traits include:
Residual Average Daily Gain (RADG) is a measure of an animal’s genetic ability for growth (post weaning gain) on a constant amount of feed. This RADG EPD will help you identify animals that can grow more on a constant amount of feed.
In order to calculate RADG EPD for you, your Association requires the following data for your cattle which can be submitted by you and/or Growsafe:
- Feed intake data must be collected between 160–480 days of age, with a test minimum of 45 days and 14 days adjustment period.
- Weaning weight, yearling weight, and in and out weights must also be recorded
- Must be in a contemporary group of at least 2 animals
*To arrange to test your cattle for feed intake please contact a Growsafe partner in your region, or one of the below options:
Feeding tests can occur anytime in the year but two months’ notice is required before commencement of trial. The test is currently a 70-day intake test with a 21-day warm up period. The minimum number for feed test is 20 head, ration ingredients will vary but will be formulated for bulls to gain 2.5 to 3 lbs per day while heifers will target 1.5 to 2.5 lbs of ADG per day. Feed test costs depend on market cost of feed (the typical range is $4.50 to $5.50/ head/day).
*To arrange for feed intake testing at Lakeland College please contact Obioha Durunna, at [email protected] or by calling 780-853-8481
The Technology Access Centre for Livestock Production (TACLP) at Olds College is also conducting feed intake testing using GrowSafe feeding systems.
*To learn more about the TACLP or for more information on accessing these services, contact Sean Thompson, TACLP Manager, at 403-556-8314 or [email protected]
Maritimes Bull Test Station is also equipped with Growsafe feed intake test systems.
*To arrange to test your cattle here contact Brad McCallum at 902-661-2855.
Cattleland National Bull Evaluation Centre has a capacity of 5,000 head that includes options for feed testing and marketing cattle.
*For more information on feed testing your cattle at Cattleland please contact Kristine Burgess at [email protected] or 403-333-5607.
Docility EPD is a measure of yearling cattle temperament, where higher numbers on parent animals indicate more docility in their calves.
• Submitted on AngusNOW and CAA worksheets
1 = Docile (acceptable, mild disposition)
2 = Restless (restless during processing)
3 = Nervous (nervous and impatient)
4 = Flighty (jumpy and out of control, quivers and struggles)
5 = Aggressive (extreme agitation) 6 = Very Aggressive (extremely violent behaviour)
Heifer Pregnancy EPD is a selection tool to increase the probability of a sire’s daughters becoming pregnant at first exposure. A higher EPD number indicates higher probability of pregnancy.
Mature Weight EPD is a measure of a sire’s genetic potential for mature weight of daughters.
Claw Set EPD will be an indicator of genetic potential for claw set on progeny, a lower number will indicate a more ideal claw set.
Foot Angle EPD will measure genetic potential for foot angle, where the ideal is a 45-degree angle at the pastern joint with appropriate toe length and heel depth. A lower number EPD is more favourable, indicating that a sire will produce progeny with more ideal foot angle.
Foot structure has a heritability estimate of 0.25, which is similar to weaning weight. This means genetic improvement for these two claw set and foot angle can certainly occur. In order to calculate the most accurate EPD for these two traits we need consistent and accurate data on claw set and foot angle.
Canadian Angus members are now able to score their cattle for claw set and foot angle at yearling, and subsequently when scoring mature cow weight. Claw set and foot angle scores range from 1–9 and the scoring scale is shown here. Management group information should group animals that have been fed and managed the same together. Complete groups (all the animals in each group) should be scored and submitted.
*Claw set and foot angle scores can be submitted on AngusNOW.
Teat and Udder EPDs will be a measure of genetic potential for teat size and udder suspension. Higher EPDs will be favourable.
Pendulous udders that have lost their suspensory support and large bottle shaped teats have been associated with increased mastitis in the cow, and delayed teat finding and suckling by her calf. This results in early culling for the cow and financial loss for the producer. Teat and udder structure is important to both seed stock and commercial producers therefore your Canadian Angus Association has developed a genetic evaluation for the traits.
Teat size and udder suspension can be measured using the scale as follows: Scores range from 1 for large, bottle shaped teats to 9 for very small teats and from 1 for very pendulous udders with a broken floor to 9 for very tight udders.
Members are encouraged to score their cows at calving and submit their scores on AngusNOW when registering calves. These scores will be used to generate teat and udder score EPDs.
Cow Longevity EPD plays an important role in the profitability, sustainability, and environmental footprint of a beef operation. Canadian Angus members enrolled in the Performance Program have for the past 30 years provided whole herd reporting (complete cow herd data). Production and cull information on these cow herds is being used by your Canadian Angus Association and the American Angus Association to develop a Cow Longevity EPD.
Gestation Length EPD will be a measure of a sire’s potential to have calves that are born within fewer days from conception. A lower number will be indicative of shorter gestation length. Gestation length EPDs are a great tool for selecting for shortened gestation length with is associated with higher calving ease and lower birth weight without compromising on growth potential. A shorter gestation period also gives females longer to recover and cycle back into heat so this is a valuable EPD.
Immunity Plus EPD—this project is funded by Genome Canada, and the Canadian Angus Association, American Angus Association and Semex Beef have come together to develop the University of Guelph High Immune Response (HIR™) test and EPD for Canadian and American Angus cattle because of the benefits that cattle that are naturally, genetically, healthier and more productive.
The consumer wants assurances that their beef is coming from healthy animals that are raised using sustainable practices. Genetic selection is often the best solution available. High immune response is hereditary and can be selected for in breeding programs. A high immune response test and EPD will help Angus producers identify animals that have superior genetic potential for high health, allowing the industry to capitalize on all the benefits of healthier animals, including decreased use of antibiotics.
Released June 2020 Black Angus
Average EPDs for all Red and Red Carrier Calves born in 2019 Click for Percentiles
Genetic Evaluation Definitions: