Fat quality affects the entire pork chain as both fresh and further processed products are subject to fat oxidation, color change, and shortened shelf-life in light of poor fat quality. The literature indicates fat quality has been important for decades, but as economic indicators encourage pork producers to use non-traditional fat sources, such as dried distiller’s grain with solubles (DDGS), in swine diets, the impact of fat quality has created challenges for end users of pork chain products. Export markets for fresh pork and domestic markets of valued added pork such as sausage and bacon are especially influenced by fat quality as these are opportunities for increased profit margin and require the delivery of high quality products to meet consumer expectations.

According to research within our lab and reports of others, the fat source in the diet is a significant driver of pork fat profile and ultimately fat quality in the final product. We expect the timing of marketing pigs to interact with dietary fat source and this relationship could alter feeding strategies of certain fat sources to optimize fat quality in pork. Therefore, in the following study, we sought to determine the fatty acid profile and iodine value of jowl and belly fat from hogs fed a diet including 20% DDGS and marketed in three cuts from a commercial facility. Iodine value was determined using three methods; chemical titrations, calculated from a fatty acid profile and using in-plant near infrared (NIR) spectroscopy. Specifically, we want to understand how traditional marketing cuts from finishing facilities affect early maturing pigs in relation to their fat profiles and how these pigs differ from their later marketed contemporaries.

Eight hundred and eighty crossbred growing finishing hogs (PIC genetics) were raised in a commercial facility with 22 pigs allotted to each pen. Twenty pens were fed a control corn and soy based diet and the remaining 20 pens were fed a diet containing 20% DDGS (Tables 1 and 2). Animal growth and performance was measured by pen body weight, average daily gain, average daily feed intake and gain to feed ratio. The heaviest hogs were marketed first removing 4, 8 and 12 head per pen in the first, second and third marketing cuts, respectively. Belly and jowl fat samples were collected 1 day postmortem from chilled carcasses in a commercial slaughter facility. Lab analysis was performed at the University of Missouri Meat Science Laboratory.

Growth performance was unaffected by the inclusion of DDGS in the diets of growing and finishing hogs. However, marketing cut changed growth parameters, specifically ADG. The hogs marketed in the second cut have a clear advantage over counterparts in the first and third cuts. By removing the fast growing, early maturing hogs in the first cut, feeder and floor space expanded, allowing the remaining hogs to more closely meet their genetic potential. The genetically superior animals grew faster and gained more thereby surpassing the slow growing, late maturing hogs left in the third cut.

Dietary fat is largely reflected in the fatty acid (FA) profiles and iodine value (IV). Fatty acid composition is more saturated in pigs fed the control corn diet, while pigs fed 20% DDGS, have a greater proportion of unsaturated fatty acids. Iodine values, regardless of determination method, mimic the fatty acid profiles. Pigs fed 20% DDGS had higher IV (greater degree of unsaturation) when compared to control counterparts and jowl fat had a higher IV then belly fat. These results suggest that feeding 20% DDGS increases IV in pork fat, but does not impede growth performance. As expected, timing of marketing will change the pen dynamics and feeding behavior to alter growth performance as well as fat tissue composition. Fat sampling depot differs for animals at varied stages of growth and should be considered when managing pork carcasses for fat quality.