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The National Swine Registry has developed a meat quality evaluation program
to estimate Expected Progeny Deviations (EPDs) as a part of its ongoing STAGES
genetic evaluation program. The Genetic Advisory Committee of the National
Swine Registry (NSR) has worked with NSR to develop the data collection protocols
and statistical tools so that participating members can incorporate EPDs on
select meat quality traits as a part of their genetic improvement program.
The Zierke Company works with NSR as they coordinate data collection. The Zierke Company delivers pigs monthly to packing companies that are working with NSR to have animals harvested and the appropriate data collected.
The Meat quality data is collected on the loin muscle at the 10th rib location approximately 24 hours after slaughter. Data collected includes, CIE L*, pH and marbling score. These traits have been determined to be favorably related to several important fresh meat and processing characteristics. Below is a further explanation of these traits.
Meat Quality Traits
CIE L*
This measurement is typically taken with a Minolta Colorimeter and is a measure of light reflectance. Higher values indicate paler meat, while lower values indicate darker meat. Pale meat is typically discriminated against in the meat case. Darker pork is often targeted for export. Boars and gilts with L* EPDs that are positive (above zero) should produce progeny with paler pork. Parents with L* EPDs that are negative (below zero) would produce progeny with darker pork. Selecting boars and gilts with negative EPDs will cause genetic change for darker pork.
pH
This measurement is taken with a pH meter and is a measure of meat acidity. Lower values suggest meat is more acid and would be less juicy and have poorer eating characteristics, while higher values would suggest meat would have better eating characteristics (more juicy, more tender). Parents with positive EPDs (above zero) should produce progeny with higher meat pH values. Boars and gilts with negative pH EPDs (below zero) would indicate that pork from their progeny would have lower pH values. Selecting boars and gilts with positive EPDs for pH will cause genetic change for higher pH values.
Marbling Score
This measurement is a visual score from 1 to 10, and approximates the percent fat within the muscle. Higher values indicate loins have more marbling and likely better eating quality while lower values indicate loins have less marbling. Parents with positive EPDs (above zero) should have progeny with more marbling. Parents with negative EPDs (below zero) would have progeny with less marbling. Selecting boars and gilts with positive EPDs would cause genetic change for increased marbling.
These data are combined with the pedigree data from Zierke animals and further merged with animals from across each breed to more accurately estimate the genetic merit of the littermates that were retained within the herd as prospective parents. After each group of animals are harvested The Zierke Company receives a listing of EPDs for the retained littermates and EPDs for sires that had progeny among the harvested animals. The Zierke Company will use these EPDs to select for improved meat quality among prospective parents and also determine which sires will be kept to continue improvement for lean growth and meat quality. The Zierke Company is committed to providing seedstock to their customers that meet the needs of the diversifying pork industry.
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