What Are EPDs
They are evaluation tools if you will, which allow anyone
wishing to use scientific historical data to make an informed decision about
the reproduction potentials of his herd.
Brief History of EPDs
First we must study a brief history of their origin. The
concept of EPDs was first introduced to seedstock beef cattle producers nearly 30 years ago with the first publication of a
National Sire Evaluation. An Expected Progeny Difference (EPD) is an estimate
of the genetic merit of an animal as a parent and is reported in the normal
units of measurement such as pounds or centimeters.
Initially when introduced, cattle
producers showed skepticism at the concept; however, over the years this has
changed to widespread acceptance. Today EPDs are the genetic selection tools
of choice for most cattle producers in the U.S.
What Do EPDs Provide?
An EPD value predicts the genetic transmitting ability of
an animal as a parent. The genetic makeup of an animal will never change, but
the amount of information we know about that animal can.
Additional information can change
our predictions about that animal as a parent.
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Obtaining & Evaluating EPDs
EPDs are obtained from genetic
evaluation systems based on Best Linear Unbiased Prediction (BLUP) theory.
Genetic evaluation systems based on BLUP theory use performance records,
such as birth, 205-day and 365-day weights, along with pedigrees, to
estimate EPD values. These systems simultaneously estimate EPD values for
direct and maternal traits, incorporate all relationships among animals
being evaluated, and use information from correlated traits in multiple
trait evaluations. These genetic evaluation systems estimate EPD values on
sires, dams and young (non-parent) animals that are comparable across herds
within a breed.
Information
Used in EPD Estimate
An EPD estimate on an animal
incorporates the animal's records and its parent records, progeny records
and sibling records, the animal's genetic ability and the environment in
which the animal was raised. To help separate genetic ability from the
influence of environment, producers supply information about the
environment in which an animal was raised through the formation of
contemporary groups.
Contemporary
Group
A contemporary group is a group
of animals born and raised together under the same management. Producers
separate cattle into contemporary groups by determining which calves were
raised in similar conditions and grouping them together.
Contemporary groups are also
determined by sex, so heifer calves are compared with heifer calves, bull
calves with bull calves and steers with steers. Calves remaining in the
same contemporary group after birth must also be measured for production
record keeping on the same day.
EPD definition - The expected
difference (in trait units, usually expressed in lbs. or %) in performance
of a bull or cow's progeny when those progenies are compared to a progeny
of a sire or dam with an EPD of zero for the trait in question. EPD values
are relative. They do not indicate absolute levels of performance. Rather,
they can be used to compare expected progeny performance of different bulls
or dams.
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Understanding & Using EPDs
Now for the meat of our
discussion: how to understand and use EPD’s. Below you will find a condensed
version of the Red Angus Association’s guide provided to ranchers for their
use in utilizing EPD information.
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The Ranchers’ Guide to EPDs
Based on the concept of Economically Relevant Traits (ERTs),producers are equipped with tools that
allow for selection on traits that directly impact
profitability.
These tools simplify the selection process,
and arm producers with the ability to better
identify
range bulls whose genetics will more positively
impact profitability.
Red Angus delivers technology in a producer-friendly
package. Red Angus’ inclusion of genomic data
into EPDs provides genetic predictions with
unsurpassed
dependability. Expressing these EPDs
on a
multi-breed base allows for simplified selection
decisions
regardless of desired breed composition.
EPDs are the most reliable predictors of an animal’s
true genetic merit. As the only major beef
breed to mandate Total Herd Reporting (THR), Red
Angus EPDs have the built-in advantage of being
calculated from 15 years of complete contemporary
group data. EPDs have “fast-tracked” beef cattle
improvement and removed much of the guesswork
associated with selecting range bulls.
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 within-herd 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.
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EPDs: What, Why & How?
Understanding ACCURACY
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?
The Answer...
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 of age as compared to calves sired by the old bull.
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).
EPDs are only as good as the data
used to calculate them. This fact led Red Angus to implement Total Herd
Reporting (THR) over two decades ago, and Red Angus continues to be the only
breed association to mandate THR for the collective Red Angus cowherd. In a nutshell, THR requires the
annual production of every Red Angus cow and the performance of every
calf raised through weaning to be reported. Only THR allows for the
accurate calculation of fertility and longevity traits, which are the
largest drivers in cowherd profitability. With THR, we know which
daughters that were exposed to breeding delivered a calf. With THR,
we can better predict which bulls’ daughters are able to bring a calf to
the weaning pen year after year. Ranchers make more accurate selection
decisions and ultimately more profit when they buy bulls whose EPDs are
backed by THR.
Red Angus' commitment to Total Herd Reporting
allows for the measurement of each female’s lifetime production history; from
being exposed to breeding as a yearling, to measuring females’ productive
lifespan. Implementing these
tools into your selection decisions will have a long-term impact on your
operation’s profitability.
Calving Ease Direct (CED) - predicts the probability
of calves being born unassisted out of 2-year-old heifers. Producers want live
calves - born unassisted. Selecting on actual birth weight is flawed; it
is influenced by non-genetic factors such as nutrition and weather
(ambient temperature). While BW EPD
removes these non-genetic
factors, Red Angus’ CED EPD is the best predictor of calving ease. The CED EPD
includes variation in BW plus other influential genetic factors such as
gestation length, calf shape, etc.
CED EPDs
4 = Top 50%
7 = Top 25%
9 = Top 10%
Heifer Pregnancy (HPG) - predicts the probability
of heifers conceiving to calve at two years of age. Many breeds offer
genetic predictions of yearling bull scrotal circumference as an
indicator of age of puberty. While puberty is a prerequisite, many factors
influence pregnancy rate. Red Angus’ HPG EPD offers a tool which selects
for what is economically relevant to ranchers - pregnant
heifers.
HPG EPDs
10 = Top 50%
11 = Top 25%
13 = Top 10%
Calving Ease Maternal (CEM) - predicts the probability
of a given animal's daughters calving unassisted at two years of age. Replacement heifers should
be able to calve on their own. Red Angus' CEM EPD offers the industry's most
reliable prediction to address that concern. It includes not only the predisposition for a female to calve unassisted, but also her contribution to her calf's
traits (birth weight, calf shape, etc.) that make it more likely to be
born unassisted.
CEM EPDs
5 = Top 50%
7 = Top 25%
9 = Top 10%
Maintenance Energy (ME) - predicts differences
in daughters’ maintenance energy requirements and is expressed in Mcal/Month. Recognizing that 70% of cowherd feed
costs are burned up in maintaining weight and condition, Red Angus’ ME
EPD allows for the selection of bulls whose daughters will require less
feed; thus, reducing cowherd expenses. Include selection pressure for ME
EPD to ensure feed costs don’t get out of line when selection is made for greater
performance and production.
ME EPDs
1 = Top 50%
-3 = Top 25%
-6 = Top 10%
Stayability (STAY) – predicts the
probability of a bull’s daughters remaining productive until at least six years
of age. Why
six? That’s how long it takes a female to breakeven given all the
expenses of development.
Red Angus’ Stayability (STAY) EPD is a selection tool to improve overall cowherd efficiency through
reducing replacement rate. Cows that stay productive, are problem free and last
longer mean a larger percentage of heifers can be cash cropped, instead of
developed as replacements.
How is Stayability EPD Calculated?
THR provides the foundation for a
reliable Stayability EPD. Once a female enters the
productive cowherd she is monitored annually for her productive ability. Only
females that produce a calf every year up until at least six years of age are
given a positive observation. Females that miss a calf or are culled for any
reason including soundness, production, disposition, body condition, etc. are
given a negative observation. Mandatory collection of Stayability observations from all Red Angus herds provides ample data for the prediction of
a bull’s ability to sire Ranch-Tested – Rancher-Trusted cowherds.
Improving Stayability enhances cowherd profitability by increasing the percentage of females that
deliver pounds and value to the weaning pen without extra labor or feed –
and do it year after year.
Stay
EPDs
11 = Top 50%
13 = Top 25%
15 = Top 10%
Traits that add weight to your bank
account!
Realizing the vast majority of commercial
operations’ revenue comes from the sale of pounds, Red Angus strives to provide
industry-leading genetic predictions for growth. This can only be achieved
through the implementation of Total Herd Reporting. Red Angus further ensures
the reliability of performance data through the use of data filters, which eliminates
data outside biological norms. The net result of these efforts - no surprises
on pay day.
Birth Weight EPD (BW) - predicts the difference,
in pounds, for birth weight, and is also used in the calculation of Red Angus'
Calving Ease Direct (CED) EPD.
BW EPDs
-1.0 = Top 50%
-2.4 = Top 25%
-3.7 = Top 10%
Weaning Weight EPD (WW) - predicts the difference,
in pounds, for
weaning weight (adjusted to age
of dam and a standard 205
days of age). This is an indicator of growth from birth to weaning.
WW EPDs
56 = Top 50%
63 = Top 25%
69 = Top 10%
Yearling Weight EPD (YW) – predicts the expected
difference, in pounds, for yearling weight (adjusted
to a standard 365 days of age).
This is an indicator of growth from birth to yearling.
YW EPDs
83 = Top 50%
95 = Top 25%
106 = Top 10%
Milk EPD (MILK) - predicts the difference in
maternal production of an individual animal's daughters as expressed by the
weaning weight of their calves.
MILK EPDs
20 = Top 50%
23 = Top 25%
26 = Top 10%
Total Maternal EPD (TM) – predicts the rancher's
actual observation of weaning weights of calves raised by an animal's
daughters. TM includes the daughter’s milk EPD plus half of her genetic
contribution to her calf's weaning weight EPD. The formula for TM EPD is:TM EPD = Milk
EPD + 1/2 (WW EPD)
TM EPDs
48 = Top 50%
52 = Top 25%
56 = Top 10%
Bred-in Carcass Value...
Red Angus is preferred among producers
who retain ownership of their calf crop.
This demand is driven from consistent feedyard performance combined with reaping premiums from
value-based grids. Furthering the mission of providing genetic predictions that
directly impact producer profitability, Red Angus recently added Carcass Weight
(CW) and Yield Grade (YG) to its arsenal of ERTs. Incorporation of these
selection tools have the power to take your
profitability to the next level.
Marbling Score (MARB) - predicts differences
for carcass marbling score as expressed in marbling score units. Higher
marbling scores are positively correlated with higher carcass quality
grades.
MARB EPDs
0.41 = Top 50%
0.57 = Top 25%
0.69 = Top 10%
Yield Grade (YG) - predicts differences
in USDA Yield Grade score and is expressed in USDA Yield Grade units. YG
EPD is calculated using the genetic predictions of CW, REA and FAT EPDs.
The reliability of Red Angus’ YG EPD is enhanced by using both
ultrasound and actual carcass data in the calculation
of REA and FAT EPDs.
YG EPDs
0.02 = Top 50%
-0.05 = Top 25%
-0.11 = Top 10%
Carcass Weight (CW) - predicts differences
in hot carcass weight and is expressed in pounds. Because Red Angus’ CW EPD
is a multi-trait model which includes birth, weaning and yearling weight
data, the prediction is not subject to culling bias. Thus, it provides a
more reliable EPD as compared to only using actual carcass weights. This
computation allows for the use of weights taken on ~57,000 animals per
year as compared to only ~1,500 animals per year with actual carcass
weight observations. Increased Carcass Weight tends to detrimentally
affect Yield Grade; the calculation of which also includes Rib Eye Area
and Fat Thickness.
CW EPDs
18 = Top 50%
28 = Top 25%
37 = Top 10%
Rib Eye Area (REA) predicts differences of
carcass Rib Eye Area
between the 12th and 13th rib. Increased Rib Eye Area
has a beneficial effect
on Yield Grade which also
includes Carcass Weight and Fat Thickness.
REA EPDs
0.10 = Top 50%
0.25 = Top 25%
0.39 = Top 10%
12th Rib Fat Thickness (FAT) predicts differences for
carcass fat
depth over the 12th rib, as
expressed in inches. Increases in fat thickness
has a detrimental effect on
Yield Grade.
FAT EPDs
0.00 = Top 50%
-0.01 = Top 25%
-0.03 = Top 10%
Building a cowherd?
■ Combine low-expense
traits (ME EPD) with acceptable revenue traits to breed efficiency into the
cowherd.
■ 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.
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.
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 - improve traits
that impact feeder profits, such as carcass traits and post-weaning gain (YW).
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 cowherd to pinpoint needed improvement for post-weaning gains.
■ Increase payweight with selection for improved CW EPD.
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 cowherd genetics:
• Cowherds of higher Continental influence
may require additional selection pressure on MARB EPD to improve quality grade.
• High-percentage British cowherds
typically benefit from selection pressure to reduce YG and increase CW.