Page 45 - Earnscleugh 2021 Catalogue eBook

COMPOSITE

QUICK REFERENCE TO ASA EPDS AND $ INDEXES
Expected Progeny Differences (EPDs): EPDs are the most accurate and effective tool available for comparing genetic levels. In
using EPDs, the difference between two sires’ EPDs represents the unit difference expected in the performance of their progeny.
For example, if sires A and B have EPDs of +10 and –5, a 15-unit difference would be expected in their progeny (moving from -5
to +10 yields 15 units). Key to using EPDs is knowing what units they are expressed in. For example, if the above case referred
to weaning weight EPDs, A would be expected to sire 15-pounds more weaning weight than B. If calving ease were the trait, A
would be expected to sire 15-percent more unassisted births in first-calf heifers; in other words, if B sired 30 assists in a group
of 100 heifers, we’d expect A to require 15 assists. A percentile-ranking chart is required to determine where a bull’s EPDs rank
him relative to other bulls in the breed. For percentile rankings or more detailed information about EPDs and $ indexes visit www.
simmental.org. Listed below are the units ASA EPDs are expressed in:
All-Purpose Index (API): Dollars per cow exposed under an Maternal Weaning Weight (MWW): Pounds of weaning
all-purpose-sire scenario. (See overleaf for more details.) weight due to milk and growth.
Back Fat (BF): Inches of backfat. Ribeye Area (REA): Square inches of ribeye.
Birth Weight (BW): Pounds of birth weight. Warner-Bratzler Shear Force (WBSF): Pounds of force
Calving Ease (CE): Percent of unassisted births when used required to shear a steak.
on heifers. Stayability (STAY): Percent of daughters remaining in the
Carcass Weight (CW): Pounds of carcass weight. cowherd at 6 years of age.
Maternal Calving Ease (MCE): Percent of unassisted births Terminal Index (TI): Dollars per cow exposed under a
in first-calving daughters. terminal-sire scenario. (See overleaf for more details.)
Milk (MLK): Pounds of weaning weight due to milk. Weaning Weight (WW): Pounds of weaning weight.
Marbling (MRB): Marbling score. Yearling Weight (YW): Pounds of yearling weight. COMPOSITE
Yield Grade (YG): Yield grade score.

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