Page 35 - C-B Charolais 2017 Annual Production Sale

AICA EPD Guide
AICA EPD Guide
Calving Ease Direct (CE) is expressed as a difference in percentage of
unassisted births in fi rst calf heifers. A higher value indicates greater calving
ease. It predicts the average difference in unassisted births with which a sire’s
calves will be born when bred to fi rst-calf heifers.
Birth Weight EPD (BW) The expected difference in average birth weight
(pounds) of progeny. Birth weight refl ects prenatal growth.
Calving Ease Maternal (MCE) is expressed as a difference in percentage
of unassisted births in fi rst calf daughters. A higher value indicates greater
calving ease. It predicts the average difference in unassisted births with which
a sire’s daughters will calve as fi rst-calf heifers when compared to daughters
of other sires.
Weaning Weight EPD (WWT) The expected difference in average weaning
weight of calves. The evaluation refl ects the genetic infl uence on pre-weaning
growth rate.
Yearling Weight EPD (YWT) The expected difference in average yearling
weight of progeny. The evaluation refl ects genetic infl uence on both pre-
weaning and post-weaning growth rate.
Maternal Milk EPD (MAT) The genetic ability of a sire’s or dam’s daughters to
express in pounds of weaning weight in her calves due to her maternal ability
through mothering instinct and milk.
Total Maternal EPD (TOTMAT) A value to predict the weaning weight
performance of calves from a animal’s daughters due to genetics for growth
and maternal ability. Total Maternal is calculated by adding ½ the WWT EPD to
the Maternal Milk EPD.
Scrotal Circumference EPD (SC) The expected difference in scrotal
circumference (expressed in centimeters) of a bull’s or dam’s male offspring
at yearling compared to progeny of all other animals evaluated. Research has
also indicated a relationship between increased SC EPD and decreased age at
puberty for daughters.
Carcass Weight EPD (HCW) Expected progeny differences for Carcass Weight
is a predictor of pounds of retail product at a constant age endpoint. Selection
for increased values should result in heavier carcasses, while selection for
decreased values should result in lighter carcass weights at the same age
endpoint. Carcass Weight EPD are expressed in pounds and is a predictor
of the differences in hot carcass weight between parents progeny at an age
constant endpoint.
Ribeye Area EPD (REA) Ribeye area is measured from a cross-sectional
area of the longissimus dorsi muscle at the 12th rib. Ribeye area is a major
component of the USDA yield grade equation and selection for increased
ribeye area should result in larger ribeyes and lower yield grades between
animals with the same carcass weight. Ribeye area has a positive relationship
with weight, the larger the animal the larger the ribeye area. Ribeye Area EPD
are expressed in square inches and is a predictor of differences in ribeye area
between parents progeny at a constant age endpoint.
Fat Thickness EPD (FAT) Fat thickness is measured at the 12th rib and is the
primary component to the USDA Yield Grade equation. Fat thickness has a
negative relationship to cutability; therefore, selection base on decreased fat
thickness should result in lower yield grades and leaner cattle given the same
age endpoint. Fat Thickness EPD are expressed in inches and are a predictor
of differences in fat thickness between parent’s progeny at an age constant
endpoint.
Marbling Score (MARB) Marbling is a subjective measure of the amount of
intramuscular fat in the ribeye muscle. Marbling score is the primary component
of USDA Quality grade and selection for increased Marbling Score EPD should
result in cattle with higher quality grades at the same age endpoints. Marbling
score has a small genetic correlation with fat, therefore producers may select
for increased marbling score EPD while not changing external fat thickness
when cattle are harvested at the same age-constant endpoint. Marbling EPD is
a prediction of the differences in the USDA subjective marbling score between
parent’s progeny at an age constant endpoint.