Expected Progeny Differences (EPD)
is the prediction of how future progeny
of each animal are expected to perform relative to the progeny of other animals
listed in the database. EPDs are expressed in units of measure for the trait,
plus or minus. Interim EPDs may appear on young animals when their perfor-
mance has yet to be incorporated into the American Angus Association National
Cattle Evaluation (NCE) procedures.
This EPD will be proceeded by an “I”, and
may or may not include the animalʼs own performance record for a particular
trait, depending on its availability, appropriate contemporary grouping, or data
edits needed for NCE.
ACC:
Accuracy is the reliability that can be placed on the EPD.
An accuracy of
close to 1.0 indicates higher reliability.
GROWTH
Calving Ease Direct (CED)
is expressed as a difference in percentage of
unassisted births, with a higher value indicating greater calvi
heifers. It predicts the average difference in ease with which a sireʼs calves will
Birth Weight EPD (BW)
expressed in pounds, is a predictor of a sireʼs ability to
transmit birth weight to his progeny compared to that of other sires.
Weaning Weight EPD (WW)
expressed in pounds, is a predictor of a sireʼs
ability to transmit weaning growth to his progeny compared to that of other
sires.
Residual Average Daily Gain (RADG)
expressed in pounds per day, is a
predictor of a sireʼs genetic ability for postweaning gain in future progeny com-
pared to that of other sires, given a constant amount of feed consumed.
Yearling Weight EPD (YW)
expressed in pounds, is a predictor of a sireʼs abili-
ty to transmit yearling growth to his progeny compared to that of other sires.
Yearling Height EPD (YH)
is a predictor of a sireʼs ability to transmit yearling
height, expressed in inches, to his progeny compared to that of other sires.
Scrotal Circumference EPD (SC)
expressed in centimeters, is a predictor of
the difference in transmitting ability for scrotal size compared to that of other
sires.
Docility (DOC)
is expressed as a difference in yearling cattle temperament,
with a higher value indicating more favorable docility. It predicts the average
difference of progeny from a sire in comparison with another sireʼs calves. In
herds where temperamental problems are not an issue, this expected differ-
ence would not be realized.
MATERNAL
Heifer Pregnancy (HP)
the heifer pregnancy EPDs are designed to character-
ize differences among sires in the Angus breed for daughterʼs heifer pregnancy.
When comparing two sires based on their heifer pregnancy EPDs (reported in
units of percentage), a higher EPD sire would be expected to have daughters
with a greater probability or chance of becoming pregnant than a sire with a
lower EPD.
Calving Ease Maternal (CEM)
is expressed as a difference in percentage of
unassisted births with a higher value indicating greater calvin
daughters. It predicts the average ease with which a sireʼs daughters will calve
Maternal Milk EPD (Milk)
is a predictor of a sireʼs genetic merit for milk and
mothering ability as expressed in his daughters compared to daughters of other
sires. In other words, it is that part of a calfʼs weaning weight attributed to milk
and mothering ability.
Mature Weight EPD (MW)
expressed in pounds, is a predictor of the difference
in mature weight of daughters of a sire compared to the daughters of other
sires.
Mature Height EPD (MH)
expressed in inches, is a predictor of the difference
in mature height of daughters of a sire compared to the daughters of other
sires.
Cow Energy Value ($EN)
expressed in dollar savings per cow per year, as-
sesses differences in cow energy requirements as an expected dollar savings
difference in daughters of sires. A larger value is more favorable when compar-
ing two animals (more dollars saved on feed energy expenses). Components
for computing the cow $EN savings difference include lactation energy require-
ments and energy costs associated with differences in mature cow size.
CARCASS
Carcass Weight EPD (CW)
expressed in pounds, is a predictor of the differ-
ences in hot carcass weight of a sires progeny compared to progeny of other
sires.
Marbling EPD (Marb)
expressed as a fraction of the difference in USDA mar-
bling score of a sireʼs progeny compared to progeny of other sires.
Ribeye Area EPD (RE)
expressed in square inches, is a predictor of the differ-
ence in ribeye area of a sireʼs progeny compared to progeny of other sires.
Fat Thickness EPD (Fat)
expressed in inches, is a predictor of the differences
in external fat thickness at the 12
th
rib (as measured between the 12
th
and 13
th
ribs) of a siresʼ progeny compared to progeny of other sires.
Back Fit Thickness:
Subcutaneous fat thickness between the 12
th
and 13
th
rib
over the longissimus muscle is the most common measure of subcutaneous fat
on a carcass. The BF thickness is directly related to the carcass yield grade.
Most reports indicate the ultrasonic determination of BF is accurate to within 1
in. of the actual measure in >70% of the animals scanned.
FAT EPD, expressed in inches, is a predictor of the difference in ultrasound fat
thickness at the 12
th
rib of a sireʼs progeny compared to the progeny of other
sires. It includes the weighted average of 60% of the rib fat measurement and
40% of the rump fat measurement.
The most recent advance in ultrasound technology has been in computer-aided
analysis of longitudinal images of the longissimus muscle to estimate intramus-
cular fat. Three quarters of the ultrasound measurements of intramuscular fat
are within 1.5% of the actual fat value.
The technology to measure marbling is still emerging. Nonetheless, direct
measurement of BF or REA and current prediction models for %IMF via
ultrasound are adequate to calculate reliable breeding values when large
numbers of cattle ore scanned. It is likely that this method of collecting carcass
information will quickly replace the traditional “kill data” collected on carcasses
at slaughter plants.
$VALUE INDEXES
Weaned Calf Value ($W)
an index value expressed in dollars per head, is the
expected average difference in future progeny performance for pre-weaning
merit. $W includes both revenue and cost adjustments associated with differ-
ences in birth weight, weaning direct growth, maternal milk and mature cow
size.
Feedlot Value ($F)
and index value expressed in dollars per head, is the
expected average difference in future progeny performance for post-weaning
merit compared to progeny of other sires.
Grid Value ($G)
an index value expressed in dollars per head, is the expected
average difference in future progeny performance for carcass grid merit com-
pared to progeny of other sires.
Quality Grade ($QG)
$QG represents the quality grade segment of the
economic advantage found in $G. $QG is intended for the specialized user
wanting to place more emphasis on improving quality grade.
The carcass
marbling (Marb) EPD and ultrasound-derived percent intramuscular fat (%IMF)
EPD contributes to $QG.
Yield Grade ($YG)
represents the yield grade segment of the economic ad-
vantage found in $G. $YG is intended for the specialized user wanting to place
more emphasis on red meat yield. It provides a multi-trait approach to encom-
pass ribeye, fat thickness and weight into an economic value for red meat yield.
Beef Value ($B)
an index value expressed in dollars per head, is the expected
average difference in future progeny performance for post-weaning and carcass
value compared to progeny of other sires.
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