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Explanation of Terms

Expected Progeny Difference (EPD)

An EPD is the best estimate of a sire’s or dam’s genetic worth, given the information available. It is the actual difference in performance a producer can expect from future progeny of a sire or dam, relative to the future progeny of an average tested parent.

Swine Testing and Genetic Evaluation System (STAGES™)

A genetic evaluation system provided to the members of the four breed associations of the National Swine Registry (NSR). STAGES™ utilizes performance records for numerous growth, carcass and maternal measures to predict the genetic value of each pig and its parents.

EPDs:

Backfat (BF):

Expressed in inches, this EPD is a predictor of the difference in external fat thickness at the 10th rib. Animals with negative (-) EPDs for backfat will produce offspring that have less backfat at harvest than offspring of parents with higher EPDs.

Pounds of Lean (LBS):

A genetic predictor of pounds of fat-free lean adjusted to a 185-pound carcass, or approximately a 250-pound live weight. This EPD is calculated from the EPDs for Backfat and Loin Eye Area. A sire with a positive (+) EPD for LBS will produce offspring that yield a higher percentage of lean and have a greater chance of obtaining full value on a lean-based carcass grid.

Days to 250 pounds (DAYS):

A prediction of an individual’s genetic merit for growth performance to a 250-pound live weight. Animals with a negative (-) EPD for DAYS will produce offspring that require fewer days to reach market weight when compared to the offspring of individuals with positive (+) genetic values for DAYS. Selection on this EPD will produce progeny that aid in earlier building close outs.

Feed Efficiency (FE):

Expressed in pounds, this EPD is a predictor of the amount of feed required to generate one pound of gain during the finishing phase of production and is calculated from the EPDs for BF and DAYS. Selection of sires with negative (-) EPDs will produce progeny that more efficiently convert feed to gain when compared to sires with higher EPDs for FE. This EPD can be used to genetically decrease feed costs.

Number Born Alive (NBA):

An expression of the genetic merit for the number of live pigs farrowed in a litter. Daughters of sires with positive (+) EPDs for NBA will farrow a greater number of live pigs than daughters of sires with lower EPDs for NBA.

Number Weaned (NW):

A genetic predictor of the total number of pigs weaned within a given parity. Daughters of sires with positive (+) EPDs for NW will wean larger litters than daughters of sires with lower genetic values for NW.

Loin Eye Area (LEA):

Expressed in square inches, this EPD is a predictor of an individual’s genetic merit for 10th rib loin eye area adjusted to a 250-pound live weight.Animals with a positive (+) EPD for LEA will produce progeny with more loin muscle when compared to the offspring of animals with negative (-) genetic values for LEA.

Wean to Estrus Interval (WTE):

Expressed in days, this EPD is a genetic predictor of the number of days required for a female to return to a serviceable heat after weaning. Daughters of sires with negative (-) EPDs for WTE will require fewer days to return to estrus after weaning than daughters of sires with higher EPDs. This EPD is the most efficient selection tool for genetic improvement of fertility and non-productive sow days.

Sow Productivity Index (SPI):

An economic index that ranks individuals for reproductive traits. SPI weights the EPDs for Number Born Alive, Number Weaned and Litter Weight relative to their economic values. Each point of SPI represents $1 per litter produced by every daughter of a sire. When sow efficiency is the primary concern, SPI may be the most effective selection tool for simultaneous improvement of maternal traits.

Maternal Line Index (MLI):

An economic index designed for selection of seedstock used to produce replacement gilts for crossbreeding programs. MLI weights EPDs for both terminal and maternal traits relative to their economic values, with approximately twice as much emphasis on reproductive traits relative to post-weaning traits. Each point of MLI represents $1 per litter produced by every daughter of a sire.

Terminal Sire Index (TSI):

An economic index designed for the selection of seedstock for use in a terminal crossbreeding program. Animals selected for high TSI are designed to excel in lean growth and efficiency from weaning to harvest. TSI weights EPDs for Backfat, Days to 250 Pounds, Pounds of Lean, and feed/pound of gain relative to their economic values. Each additional index point difference is equal to $0.10 per market hog.

Actual Data:

Weight Per Day of Age (Wda):

Based on actual weight and age, this measure is the weight gained per day of age averaged over the life of the pig.

10th Rib Backfat (Bf):

Expressed in inches, this is an actual ultrasound measure of backfat at the 10th rib and is adjusted to 250 pounds.

Loin Eye Area (Lea):

Expressed in square inches, this is the actual ultrasound measurement of the loin eye size at the 10th rib and is adjusted to 250 pounds.

Intramuscular Fat (Imf):

Expressed as a percentage, this value is an ultrasound measure of the lipid content of the loin muscle. Higher levels of Intramuscular Fat (IMF) are desired for meat quality based markets.

Actual Number Born Alive (Nba):

This value is the actual number of pigs born from the dam’s parity when the pig was born and are measurements taken from the pig’s dam.

Actual Number Weaned (Nw):

This value is the actual number of pigs weaned from the dam’s parity when the pig was born and are measurements taken from the pig’s dam.

Litter Weight (Lwt):

This is the actual cumulative weight of all pigs weaned from the pigs birth litter.This weight is recorded on the pig’s dam and is adjusted to 21 days of lactation.