Page 31 - C-B Charolais Bull and Heifers Production Sale – March 28, 2023

AICA EPD Guide

Calving Ease Direct EPD (CE) is expressed as a difference in
percentage of unassisted births in first 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 first-calf heifers.

Birth Weight EPD (BW) The expected difference in average birth
weight (pounds) of progeny. Birth weight reflects prenatal growth.

Weaning Weight EPD (WW) The expected difference in average
weaning weight of calves. The evaluation reflects the genetic
influence on pre-weaning growth rate.

Yearling Weight EPD (YW) The expected difference in average
yearling weight of progeny. The evaluation reflects genetic
influence on both pre-weaning and post-weaning growth rate.

Maternal Milk EPD (MILK) 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.

Calving Ease Maternal EPD (MCE) is expressed as a difference
in percentage of unassisted births in first 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 first-calf heifers when compared to daughters of other
sires.

Total Maternal EPD (MWW) 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 WW EPD to the Maternal Milk EPD.

Terminal Sire Index (TSI) The AICA Terminal Sire Index is a
formal method of combing Expected Progeny Differences (EPD)
– BW, WW, YW, REA, CW, MARB and FAT – into one single value
on which to base selection decisions. The TSI uses estimates of
the genetic relationships between traits with an economic default
value based on three year rolling USDA data.

The TSI represents a dollar index per terminal progeny produced
for a bull in the AICA database, ranking them for profit potential.
This dollar index is to be interpreted much like single trait EPD.
For example, if Sire A’s index is $191.66 and Sire B’s index is
$200.00, then we would expect Sire B’s offspring to average
$8.34 more net return ($200.00 minus $191.66) than Sire A’s
offspring.