EPD Data Explained

 Calf Data

CE:    Calving Ease--Percent of unassisted Births,  The HIGHER the number the better

BW:   Birth Weight-- Pounds of birth weight,  the LOWER the number, the lighter the calves will be.

WW:  Weaning Weight-- Pounds of weaning weight,  the HIGHER the number,  the more pounds weaned.

YW:   Yearling Weight-- Pounds of Yearling weight,  the HIGHER the number, the more pounds as a yearling.

 Maternal Data

MCE:  Maternal Calving Ease-- Predicts calving ease of bull's daughters, the HIGHER the number the better.

MM:  Maternal Milk-- Pounds of calf weaned by bull's daughters.  Available feed resources will dictate to an extent how much milking ability should be selected.

MWW:  Maternal Weaning Weight-- Like Maternal Milk, this number measures the difference in pounds of calf weaned by a bull's daughters.

STAY:  Stayability-- Stayability is defined as the probability that a sire’s daughters entering the herd will stay in production through 6 years of age. The Stayability EPD provides an estimate of how long a sire’s daughters will stay in the herd compared to another sire in the same evaluation. Higher values indicate greater stayability.

Carcass Data

CW:   Carcass Weight-- Estimates average differences in carcass weight

YG:   Yield Grade-- (%) Estimates the average differences in cutability at a given end  point.

Marb: Marbling-- (numerical marbling  score) avg. quality grade difference where one  point=one USDA.

BF:   Inches of back fat measured over the 12th-13th rib (Ultrasound).

REA:  Square inches of rib eye. Yearling cattle should have about 1.0 or 1.1 sq. in. of ribeye area per 100# of body weight. (Higher for younger calves; less for older calves due to growth curve) (ultrasound)

API:   All Purpose index-- Evaluates sire for use on the entire cow herd with the portion of their daughters required to maintain herd size retained and the remaining heifers and steers put on feed and sold grade and yield.

TI:   Terminal Index-- Evaluates sire for use on mature Angus cows with all offspring put on feed and sold grade and yield.

Using API and TI:

 First determine which index to use: if you are keeping replacements use API: if selling offspring use TI.  Then, just as with EPDs, zero in on the unit difference between bulls.  As described above, units are in dollars per cow exposed.  The difference can be used to determine how much a bull is worth as compared to another.  Or, put another way,  how much you can pay for one bull as compared to another.  For example:  when buying an all-purpose type sire, you can quickly figure a bull scoring +100 for APIs is worth an extra $6000 over a +50 bull if both are exposed to 30 cows over 4 years. ($50 dollar difference x 30 head x 4 years=$6000).  A percentile ranking chart is required to determine where a bulls index value ranks him relative to other bulls in the breed.  For percentile rankings or more detailed information about EPDs and dollar indexes visit  www.simmental.org .

Please remember that EPDs are just a tool to be used in your selection process.  It is not a 100% percent accurate science, but it is a good start toward finding bloodlines that quite possibly excel in desirable characteristics.