MISSOURI SWINE IMPROVEMENT ASSOCIATION ON-FARM EVALUATION AND GENETIC IMPROVEMENT PROGRAM

Accurate identification of genetically superior boars and gilts will allow commercial swine producers the opportunity to produce pork more efficiently, thus increase profitability. The choice of seedstock source is one of the most crucial decisions a producer will make. A seedstock producer should be utilizing a well-planned genetic improvement program that includes the latest technologies available to measure body composition in the live animal and estimate genetic merit of economically important traits. This will provide the seedstock producer the means to improve the genetic merit of the herd and the commercial producer with accurate information to better quantify the genetic worth of potential replacements.

The MSIA...
The Missouri Swine Improvement Association (MSIA) is a not-for-profit organization formed to stimulate further improvement in the efficiency of Missouri pork production. The MSIA is working in cooperation with the University of Missouri Animal Science Extension, the Missouri Pork Producers Association and the Missouri Department of Agriculture. The University of Missouri is coordinating an on-farm-testing program that utilizes the most recent advancements in the measurement of body composition and the estimation of genetic merit.

The On-Farm Program...
On-farm evaluation of market weight boars, gilts and barrows is available to both seedstock and commercial producers. Growth, backfat and loin muscle area are measured by a University Extension technician. A weight is taken and backfat and loin muscle area are estimated in the live animal using Real-Time ultrasound. All three traits are adjusted to a constant weight of 230 pounds. Results of the on-farm evaluation are promptly reported to the producer.

The Genetic Improvement Program...
Genetic evaluation of specific traits is available to seedstock producers who pedigree their purebred pigs. Data from the on-farm evaluation are forwarded to the appropriate breed association where the genetic evaluation is processed. Expected progeny differences (EPD) are reported for number born alive, 21-day litter weight, days to 230 pounds and backfat. Seedstock producers are able to make genetic progress more rapidly by incorporating genetic evaluation data into their selection program. Commercial producers can utilize genetic evaluation data to more accurately access differences in the economic value between individual boars or gilts.

Real-Time Ultrasound...
Accurate measurement of carcass traits in the live animal is crucial for genetic progress to be made in carcass quality. Ultrasound has been used to evaluate swine and cattle for more than 30 years; however, use has increased recently due to advancements in technology coupled with an increased awareness of carcass quality. A linear measurement of fat and loin depth is taken with A-mode because this early ultrasound technology utilizes only a single transducer. Real-Time or B-mode is the latest in ultrasound technology and utilizes a linear array transducer that contains 100 crystal elements that send and receive 15-30 signals per second. A two dimensional image of fat and muscle is produced, allowing for the estimation of area measurements.

Taking Real-Time Measurements...
Measurement with Real-Time ultrasound requires the following items: electricity, a table, a restraining device and scale. The Real-Time equipment must be placed on a table or other secure stand that is near electricity and safe from pig movement. The restraining device should be located next to the table. A scale will often work well for restraint if it is open on the top to allow for unobstructed placement of the Real-Time probe.

Accuracy of Real-Time...
To quantify the accuracy of Real-Time ultrasound, the University of Missouri has compared live ultrasound estimates of fat depth and loin muscle area to carcass measurements from over 200 pigs. Strong relationships between Real-Time and carcass measurements were found for both traits (correlations were .86 and .83 for fat depth and loin muscle area, respectively). Comparing the correlations of A-mode and Real-Time estimates with carcass measurements, Real-Time was 26% more accurate for backfat and 151 % more accurate for loin muscle area. Real-Time estimates rank pigs closer to carcass rankings, as compared to A-mode, thus the accuracy of selection for carcass composition is increased.

Make Appropriate Comparisons...
The environment under which a pig is tested can greatly influence performance. To eliminate as much of the non-genetic influence as possible, actual performance data of potential replacements should only be compared to contemporaries or pigs tested under the same environment. An EPD eliminates known environmental effects. This means comparisons of EPDs can be made across contemporary groups. Most EPDs are only comparable within herd. EPDs can only be compared across herds if they are from an across herd or national animal evaluation. Care should be taken to make sure only appropriate comparisons are made anytime performance data or EPDs are used as a selection tool.

MSIA On-Farm Report...
The University of Missouri reports the results of the on-farm evaluation back to the producer. Traits reported include days to 230 pounds, tenth rib backfat depth and loin muscle area measured at the tenth rib. Backfat is also measured at the last rib and reported as an average with tenth rib backfat. Percent lean is predicted from the measurements of tenth rib backfat depth and loin muscle area. Backfat, loin muscle area and percent lean are adjusted to a constant weight of 230 pounds. Additionally, trait ratios, a carcass index and a general index are made available to the producer.

Trait Ratios...
A trait ratio compares the performance of an individual relative to its contemporaries. An animal that is average for a given trait will have a ratio of 100. An animal that is superior for the trait will have a ratio greater than 100 and a below average animal will have a ratio less than l00. The individual's superiority or inferiority relative to its contemporaries can be quickly identified. Ratios are available for tenth rib backfat, average backfat, loin muscle area and days to 230 pounds.

MSIA Indexes...
An index combines two or more traits into a single measure based on the relationship among traits and the economic value of the individual traits. The MSIA on-farm report includes two indexes: general and carcass. Traits included in the general index are days to 230 pounds, backfat and loin muscle area. Proportionate emphasis in the general index is 50, 33 and 17% for days to 230, backfat and loin muscle area, respectively. Selecting above average (> 1 00) replacements using the general index will result in increased lean growth rate. Backfat and loin muscle area are included in the carcass index in a proportion of 67 to 33%, respectively. Selecting replacements above average for the carcass index will result in a higher percent carcass lean.

EPDs...
Expected progeny differences or EPDs are predictions of future progeny performance. An EPD is the expected performance of progeny out of a sire or dam relative to some reference point. The best point of reference to use is an EPD from another individual. The actual difference between EPDs from two individuals within the same herd is a prediction of the expected difference in progeny performance.

Calculating EPDs...
An EPD is estimated from on-farm measurements taken on individual animals and submitted to the breed association in contemporary groups. A contemporary group consists of animals tested together, allowing all individuals an equal opportunity to perform. The performance of an animal relative to the others within the same contemporary group is the basis for EPD calculations. All available information including the performance of the animal itself, animals in the pedigree, full- and half-sibs and progeny is used in the calculation of EPDS. Contemporary group differences are corrected for, so EPDs are comparable across groups.

Accuracy of EPDs...
The accuracy or confidence that can be placed in an EPD is a function of the amount of information available on a given animal. Accuracies range from 0 to 1.0 and increase in value with the addition of more information. A low accuracy does not mean that a younger or less proven individual has low genetic potential, rather that the likelihood of the EPD changing in value is greater than an animal with a high accuracy. An EPD is expected to change as new data is added; however, this possible change will decrease as the accuracy increases. For this reason the most current EPD information available should always be used.

Majority Herd Testing...
Testing all boars, gilts and barrows that management and facilities will allow increases the amount of information available on each animal and thus increases the confidence that can be placed in an EPD. Additionally, testing only selected individuals may result in EPD estimates that are biased. A minimum level of testing for seedstock producers should include all market weight boars and gilts within a line.

Within Versus Across Herd EPDs...
Breed associations estimate EPDs on a within herd and an across herd basis. A within herd EPD is only relative to pigs within a given herd and is not comparable to EPDs from any other herd. However, an across herd EPD is from a national animal evaluation and is relative to pigs from all herds included in the analysis. Within herd EPDs are calculated after the growth and backfat data for a contemporary group is submitted to the breed association. Across herd EPDs are processed every six months and are currently available only in some of the breeds. With the current evaluation technology, EPDs are never comparable across breeds.

Selecting for Litter Size...
Increasing litter size can be accomplished by selecting sires and dams that have a large positive EPD for number born alive. An EPD for number born alive is a measure of the genetic potential for litter size that a sire (or dam) is expected to transmit to his (or her) daughters. Male progeny also receive the genetics for number born alive, but it is a trait that can only be measured in females. For example, compare a boar that has a number born alive EPD of +0.l to a boar with an EPD of -0.1. The difference between the EPDs is 0.2 pigs born alive, so on the average daughters out of the sire with the EPD of +0.l are expected to have 0.2 more pigs born alive per litter. This is true if the boars are mated to sets of females with the same genetic potential for number born alive, because one-half of the genetics for litter size will come from the sows.

Selecting for Litter Weight...
Maternal ability can be improved by selecting sires that have a large positive EPD for 21-day litter weight. An EPD for 21-day litter weight is a measure of the genetic potential for weaning weight that a parent will pass to its daughters (and sons). Compare the 21 -day litter weight EPDs of two boars for example purposes. A boar with an EPD of +4.0 is expected to sire daughters that will wean litters that are on the average 6 pounds heavier that a boar with an EPD of -2.0.

Selecting for Growth Rate...
Increasing the growth rate or decreasing the days to market can be accomplished by selecting for large negative days to 230 pounds EPDs. An EPD for days to 230 pounds is a measure of the genetic potential for growth that a parent is expected to pass to its offspring. For example, a boar with an EPD of -3.0 is expected to sire offspring that on the average reach 230 pounds 4 days faster than a boar with an EPD of + 1.0. Remember this assumes that each boar is mated to females that are genetically similar for growth and performance is averaged over a large number of progeny.

Selecting for Backfat...
Carcass quality, as measure by percent carcass lean, can be improved by selecting for large negative backfat EPDs. A backfat EPD is a measure of the genetic potential for fat depth that a parent is expected to pass to its progeny. A boar with an EPD for backfat of -.06 is expected to sire progeny that are .05 inches leaner than a boar with an EPD of -.01. However, notice that both EPDs are in a desirable direction or numerically below 0. Both boars would be above herd average for backfat.

Terminal Line Index...
The terminal index combines the genetic estimates (EPDs) for days to 230 pounds and backfat into a single measurement based on genetic relationships between traits and the economic value for each trait. In addition, feed efficiency is accounted for in the index by including the genetic relationships between growth, backfat and feed efficiency in the index calculations. This index should be used to select boars that will sire only market progeny.

Economics of Terminal Index...
Using this index will allow a producer to better compare the economic worth of potential terminal sires. The difference in index points between pigs has an economic meaning. Each index point difference is worth $1 for every 10 pigs produced ($0.1 per pig). For example, compare a boar with a terminal sire index of 110 to one with an index of 95. Assume the boar is expected to sire 400 market weight progeny or 40 groups containing 10 pigs each. The difference between the indexes for the two boars is 15 points. This means for every 10 pigs produced the boar with an index of 110 is worth $15 more or every pig sired by the high indexing boar is expected to be worth $1.50 more. Since the boar is expected to sire 400 market progeny, the high indexing boar is worth $600 more (40 groups time $15 per group). A premium of up to $600 can be paid for the high indexing boar to realize a return on investment.

Maternal Line Index...
The maternal line index combines the EPDs for number born alive, 21 -day litter weight, days to 230 pounds and backfat into a single measurement based on the genetic relationships between traits and the economic value for each trait. This index should be used as a tool to select boars that will produce replacement females. You may want to pay attention to the EPDs for the individual traits when using the maternal index. An individual may be far superior for one or two traits and inferior for the others, but still have an index above l00. Make sure the individual has a high maternal index, along with a good balance of EPDs for the traits that you wish to emphasize.

Economics of Maternal Index...
Using this index will allow a producer to better compare the economic worth of sires that will be used to sire replacement females. An economic comparison between boars is available based on the numerical difference in the maternal index of two boars. Each index point is worth $1 for every litter produced by a daughter out of that sire. For example purposes, compare a boar with a maternal index of 105 with one that has an index of 95. Assume the maternal boar is expected to sire replacement females that produce 75 total litters. The difference between the indexes of the two boars is 10 points. This means that every litter out of a daughter of the high indexing boar is expected to be worth $10 more. The high indexing boar is expected to be worth $750 more (75 litters times $10 per litter). A return to investment should be realized if a premium of up to $750 is paid for the high indexing boar.

Where to Get EPD Information...
Within herd EPDs are available from seedstock producers who are participating in their respective breed's genetic evaluation program. Within herd EPDs are processed and made available to the seedstock producer shortly after each contemporary group is removed from postweaning test. Participating seedstock members of the MSIA have genetic evaluation data available. For a current listing of participating herds contact Rick Disselhorst, University of Missouri Extension Ultrasound Technician, at (573) 882-7418. Across herd EPDs are currently processed by some of the breeds. The national evaluations are conducted semi-annually and a partial listing of the top ranking sires is published in the respective breed journal. A complete sire listing is available through the breed association office.

Use EPDs as a Management Tool...
An EPD should be considered a management tool used by your commercial operation. Using EPDs as a selection tool will increase the accuracy of selection over either visual appraisal or individual performance data. Selecting replacements with the aid of EPDs will allow commercial swine producers to invest more wisely in seedstock and thus profit.

Cost of MSIA Program...
The MSIA on-farm program supports itself from fees charged for ultrasound evaluation. The cost to seedstock producers is $20 per litter. For commercial and specific cross gilt producers the charge is $100 for up to 25 head and $3 for every additional pig. The fee for fairs and shows is $6 per head plus expenses. A minimum trip fee of $100 is required; however, the minimum can possibly be waived if additional stops can be coordinated in the same area.

Availability and Scheduling...
The on-farm evaluation portion of the program is available to all Missouri seedstock and commercial producers. The genetic improvement program is available only to seedstock producers with pedigreed animals and who test a majority of their herd. Advanced scheduling of at least 2 to 4 weeks is suggested to secure a desired date. For further information on pricing and scheduling call the University of Missouri Animal Science Extension at (573) 882-7418.

E-mail questions concerning this document to:
Rick Disselhorst