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Oklahoma Beef, Inc. • Thursday, March 28, 2013 7
HEREFORD • EPDs & $PROFIT INDEXES
Trait CED BW WW YW Milk M&G CEM SC
EPD +0.6 +3.5 +51 +80 +23 +49 +2.6 +1.0
Trait Fat REA Marb BMI$ CEZ$ BII$ CHB$
EPD –.002 +.55 +.09 Index +17 +15 +15 +21
1. Calving Ease – Direct (CED)
CE EPDs are based on calving ease scores and birth weights. More positive
EPDs are favorable and indicate easier calving. The EPD for direct calving ease
indicates the influence of the sire on calving ease in purebred females calv-
ing at two years of age.
2. Birth Weight (BW)
Birth weight is an indicator of calving ease. Larger BW EPDs usually, but not
always, indicate more calving difficulty.
3. Weaning Weight (WW)
WW EPD reflects pre-weaning growth. Calves sired by a bull with a +30 lb. WW
EPD should have a 20 lb. advantage in 205-day adjusted weaning weight com-
pared to calves sired by a bull with an EPD of +10.
4. Yearling Weight (YW)
YW EPD reflects differences in the 365-day adjusted yearling weight for prog-
eny. It is the best estimate of total growth.
5. Maternal Milk (Milk)
The milking ability of a sire’s daughters expressed in pounds of calf weaned.
It predicts the difference in average weaning weight of sires’ daughters’ prog-
eny due to milking ability. This difference in weaning weight is due to total
milk production over the entire lactation.
6. Maternal Milk & Growth (M&G)
Maternal Milk & Growth reflects what the sire is expected to transmit to his
daughters for a combination of growth genetics through weaning and genet-
ics for milking ability. It is an estimate of daughters’ progeny weaning weight.
It is equal to one-half the animal’s weaning weight EPD, plus all of his milk
EPD. No accuracy is associated with this since it is simply a mathematical
combination of two other EPDs. Sometimes referred to as “total maternal” or
“combined maternal.”
7. Calving Ease Maternal (CEM)
The MCE EPD indicates how easily a sire’s daughters will calve at two years
of age. When compared to the daughters of other sires.
8. Scrotal Circumference (SC)
Measured in centimeters and adjusted to 365 days of age, SC EPD is the best
estimate of fertility. It is related to the bull’s own semen quantity and quality
and is also associated with age at puberty of sons and daughters. Larger SC
EPDs suggest younger age at puberty. In this genetic analysis, a multiple-trait
model was used for scrotal circumference. Weaning weight was used as a
predictor variable to increase the prediction accuracy of SC EPDs. Therefore,
an animal with a weaning weight EPD should also have a SC EPD.
9. Rib Fat (Fat)
The Fat EPD reflects differences in adjusted 365-day, twelfth-rib fat thickness
based on ultrasound measurements of live yearling cattle. Sires with low, or
negative, Fat EPDs are expected to produce leaner progeny than sires with
higher EPDs. Ultrasound measures have been shown to be highly correlated
with the performance of slaughter progeny. Some of this data is also included
in the genetic analysis. All data is expressed on an ultrasound scale.
10. Ribeye Area (REA)
REA EPDs reflect differences in an adjusted 365-day ribeye area measure
based on ultrasound measurements of live yearling cattle. Sires with relatively
higher REA EPDs are expected to produce better muscled and higher per-
centage yielding slaughter progeny than will sires with lower REA EPDs
11. Marbling (Marb)
Marbling EPDs reflect differences in an adjusted 365-day intramuscular fat
(marbling) score based on ultrasound measurements of live yearling cattle.
Breeding cattle with higher Marbling EPDs should produce slaughter progeny
with a higher degree of intramuscular fat and therefore higher quality grades.
12. Baldy Maternal Index (BMI$)
A maternally focused index that has a production system based on 1000 Here-
ford x Angus females with a progeny harvest endpoint directed toward Cer-
tified Hereford Beef (CHB). This index is more critical of CE than the BII$ and
also has significant weight on fertility. There is positive weight on WW and a
slightly negative weight on YW, which promotes early growth and then a slow
down on growth to keep mature size manageable. The emphasis of Marbling
is greater than the emphasis of REA. This is true because of the price differ-
ence of the Choice–Select spread and the fact that there is very little incen-
tive to produce cattle better than a Yield Grade 3. The question comes up
concerning the fact that the CHB program has been successful because of
the acceptance of Select grade cattle. In answer to this, we are using a cross-
breeding production system that could sell cattle on several grids and that
the CHB program is installing a choice product. This index is geared to serv-
ice any commercial program that runs British cross cows.
13. Calving Easy Index (CEZ$)
A general purpose index that focuses on identifying bulls that can be used on
heifers and then ultimately the calves will be marketed through CHB. As you
might expect, CE and MCE carry significant weight in this index along with
fertility. There is very little weight put on growth traits and less emphasis on
carcass. Remember, this is a general index that is specifically designed to be
used in a heifer program.
14. Brahman Influence Index (BII$)
A maternally focused index that is based on a 1000-head cow herd of Brah-
man x Hereford cross cows. The progeny for this index will be harvested in a
commodity-based system, since CHB does not accept Brahman-influenced
cattle into the program. This index has less emphasis for CE than any of the
other indexes. There is emphasis on both REA and Marbling, since the cattle
will be harvested through a commodity market. The largest emphasis is in
fertility, which is measured solely by Scrotal Circumference at the present
time. Obviously, the target for this index is the producers in the Southern re-
gions of the US, where the bulls are typically sold to commercial cattlemen
who have Brahman-influenced cow herds.
15. Certified Hereford Beef Index (CHB$)
A terminal sire index that is built on a production system where Hereford bulls
sire calves for the CHB market. There is some pressure put on CE and then
positive weight on both WW and YW. Remember that all offspring in this index
are harvested, so they need to be born alive and then grow fast at all stages
of life. Of course, we have a much higher emphasis on fat in this index, as we
want the cattle to stay lean. There is also a significant weight on both REA
and Marbling, with more emphasis again on Marbling. This index would be
used by producers who have a target of producing bulls for a terminal breed-
ing program. This index could be used heavily in the Midwest, where bulls are
used in rotational breeding programs to produce cattle in a retained-owner-
ship program, or simply sold to backgrounders. This is the only index that has
no emphasis on fertility. Remember that nothing is retained in the herd.
BREED AVERAGE EPDs & $PROFIT INDEXES FOR
2011-BORN HEREFORD CALVES
EPD and $Profit Index explanation adapted from the American Hereford Association’s Spring 2013 Sire Summary
Remember that no across-breed EPD comparisons can be made.