Fat quality is an important component of overall pork quality and consumer acceptance of pork, but, prior to this research, little was known about genetic differences, relationships amongst anatomical sites of pork fat, and the relationship between pork fat quality (e.g., iodine values) and measurements of meat quality (e.g, pH, tenderness, and color). This experiment was, therefore, designed to determine the genetic differences in fat quality (iodine value) that exist amongst pigs (n=352) from six purebred lines (Berkshire, Chester White, Duroc, Landrace, Yorkshire, Hampshire) and one commercial crossbred line fed commercial diets with dried distillers grains with solubles (DDGS) inclusion at 30% of dietary dry matter. Additionally, this experiment was designed to determine the relationship between fat quality of three anatomical sites (jowl, back, and belly) and to determine if the fat quality of the back and belly could be predicted from the fat quality of the jowl. Iodine values of backfat were also assessed as predictors of meat quality. Finally, performance data (average daily gain and percentage of lean tissue at time of harvest) were collected and breed comparisons were made. The data generated from this experiment indicate that breed differences in fat quality exist and that all pigs had fat that was under the threshold iodine values for pork fat set by most meat packers (i.e., 73 to 75), even though these commercial diets included 30% DDGS of dietary dry matter. Differences in fat quality of the anatomical sites measured within individual breeds also indicate that the anatomical site from which the fat sample is taken affects the measured iodine value. Jowl fat quality (iodine value) also was found to be an accurate predictor of fat quality of both the back and belly. Iodine value of backfat was significantly and negatively correlated to meat quality of the pork chop (i.e., higher iodine values predicted lower meat quality of the pork chop). Performance data indicate that Crossbred, Duroc, and Yorkshire pigs performed the best of these seven breeds, with the greatest average daily gain and percent fat-free lean tissue at the time of harvest. The results of this experiment indicate that iodine values measured from the jowl can be a powerful tool in predicting fat quality of both the back and the belly fats. These results additionally indicate that, under our experimental conditions, 30% dietary dry matter inclusion of DDGS did not result in pigs with fat that would be considered unacceptable to meat packers.

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