Understanding EPDs in Cattle

Understanding EPDs in Brahman Cattle

By Keaton Dodd

Breeding cattle is a great challenge. For every improvement you attempt to make, it seems like there is a negative that comes along with it. Many people, including myself, are strong advocates for selecting cattle based on phenotype (meaning the way animal’s look), and that is certainly something that will never go away.

But what if I told you there was a more simplistic way to manage mating decisions?

With EPD’s, that’s possible. EPDs are a way to use a numerical value to compare animals for a specific trait. 

You may ask, what is an EPD? What does it even stand for?

An EPD, also known as Expected Progeny Difference, is a prediction of transmitting ability for a specific trait from parent to calf.

EPD’s are fluid. They are not a fixed value.

Animal’s EPD’s change as more records come in. Some breeds, like Angus, update an animal’s EPD values daily as new cattle records are submitted. The ABBA currently updates it’s EPD values 2-3 times a year.

Data experts calculate EPDs using records that individual breeders submit for performance, pedigree, and progeny. For example, if someone submits performance on a new calf crop with 10 calves sired by Dutton, those figures are put into Dutton’s EPD calculations and Dutton’s EPD value for BW change.

Keep in mind though, EPD’s are only as good as the data turned in.

Inaccurate number submitted = inaccurate number for the EPD. That’s why is super important to take accurate measurements, and never “guess” at what an animal weighs.

Or even worse, never ever just turn in a random number. This type of recklessness ruins the integrity of EPDs.

ABBA EPDS and Suggested Selection Trends

CED- Calving Ease Direct- This number should be high. This considers birthweight as well as calf shape and how it relates to dystocia.


BW- Birth Weight- We want this figure low. This solely accounts for the weight of the calf at birth.


WW- Weaning Weight- Select for higher numbers. This is a measurement of predicted weaning weights for the calves by the listed individual.


YW- Yearling Weight- Select for higher numbers. This is a measurement of predicted yearling weights for the calves by the listed individual.


M- Milk- Select to fit environment. Can differ from operation to operation. A prediction of weaning weight differences due to milk and maternal ability of the dam.


TM- Total Maternal- Select for this to be high.Total Maternal is a measure of milk plus weaning weight.


CEM- Calving Ease Maternal- This should be higher. This is a prediction of a cow’s ability to calve unassisted.


SC- Scrotal Circumference- Use as an indicator of fertility and sexual maturity of a bull’s daughter. Predicted measurement of circumference, usually done in centimeters


DOC- Docility- This figure should also be high. Predictor of temperament.


FS- Frame Score- Dependent upon operation goals. Use to increase or decrease frame score.


Carcass EPD Values

TEND- Tenderness- Higher is considered better. Used to follow the shear force method of predicting tenderness.


YG- Yield Grade- The more negative the better. Use if you want to improve numerical yield grades across your herd. Important for outfits that retain ownership.


CW- Carcass Weight- A higher numerical value correlates to an increase in carcass weight.


REA- Rib Eye Area- Select for a higher number if you are interested in increasing total muscle across herd.


MB- Marbling- Higher is considered more ideal. Selection of higher MB should result in an increase in average quality grade.


FT- Fat Thickness- Predicts subcutaneous fat levels, which are associated with poorer yield grades. This could ultimately hurt carcass value therefore most would consider a lower value more ideal.


Indexes

$Bull- Terminal Index- This all revolves around the carcass grid. If you don’t sell your cattle on the carcass grid (which very few if any Brahman breeders do) then this really may not help you. Carcass weight carries the largest factor in this index. If you selected cattle using this index, you would expect to see an increase in frame size of your cattle. Calving ease, docility, and carcass also are factored into this value. This index was designed with the seedstock producer in mind who wants to market bulls to both commercial and purebred breeders.


$Queen- Maternal Index- This index would help you improve your cow value without increasing frame, milk, or fat. This number is heavily influenced by docility, scrotal circumference, and calving ease. It’s designed to help you select better replacement females.


The Truth behind EPD’s: a look at accuracy

The most common complaint from producers about EPD values is “they aren’t accurate so why use them.”

That’s where accuracy values come in. Accuracy values are the little number right below the EPD. It’s usually going to be something like 0.XX. This is a percentage of accuracy. The closer to 1.0 – the more accurate the number is.

This number, without getting too in depth, sets a window in which the large majority of that animal’s progeny will fall for a specific trait.

As that accuracy value increases, the standard deviation of the trait gets smaller which makes more of the calves fall much closer to that given value.

For the doubters, truth is, we are the only ones to blame if we do not feel like we can trust our EPDS.

The science is proven successful, so then where do the shortcomings develop?

Honestly, if you are struggling with the accuracy of your EPD’s it’s one of two things…. either you turned in inaccurate records, or you didn’t turn them in at all.

The best way to improve the accuracy value of your EPD is to first turn in all phenotype records (weights, carcass measurements, etc.) on the individual in question, as well as all their progeny. 


The Big Picture

EPD’s alone aren’t enough.

Phenotype alone, not enough.

To get the most out your cattle, it’s best to initiate a well-rounded breeding system that encompasses phenotype selection, traditional EPD’s, and Genomics that add DNA information to boost your confidence level.

If we plan on keeping profit and production at the forefront of our operation goals, then we must embrace modern technological advances. We have made monstrous strides in the beef industry over the last few decades, and if we want this business to be around for our children and grandchildren to enjoy, then we must continue to accept change and employ technologies that add value to our outfits bottom-line. Sustainable beef production is the next great hurdle our industry faces, and we cannot get it done without all the tools at our disposal. 

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