CategoryAnimal Science - Swine Nutrition
Date Full Report Received03/30/2011
Date Abstract Report Received03/30/2011
Funded ByNational Pork Board
The large demand for corn for ethanol production has resulted in marked increases in corn prices and a resulting increase in feed costs for swine producers. The large amounts of distillers dried grains with solubles (DDGS), one of the major by-products of ethanol production, is now a viable and less expensive alternative feed ingredient for use in swine feeds. Questions are being asked regarding the amount of DDGS that can be used in swine feeds without causing reduced performance of pigs or soft bellies that are discriminated against by pork processors.
Previous research funded by the National Pork Checkoff showed that growing-finishing pigs could be fed as much as 45% DDGS in the diet with only a slight (2-3%) reduction in pig performance. However, this amount of DDGS in the diet caused softer bellies and high iodine values (a measure of the relative amount of unsaturated fatty acids in the carcass fat). However, in another study funded by the National Pork Checkoff, it was found that processing characteristics of pork bellies and eating quality of bacon, sausage, and loin chops were not negatively affected by this feeding this high dietary level of DDGS.
The objective of this study was to determine if withdrawal of a high level (45%) of DDGS from the diet during the final 2, 4, or 6 weeks of the finishing period or if the addition of a harder, more saturated fat (tallow) to a diet containing DDGS would prevent the softer bellies and high iodine numbers that occur when high levels of DDGS are fed. In addition, the study allowed us to further evaluate the effects of dietary inclusion of DDGS on the processing characteristics of cured bellies, physical characteristics of sliced bacon, and eating quality of bacon and loin chops.
In summary, this study clearly shows that some of the belly firmness problems and elevated iodine values in carcass fat that are associated with the feeding of high levels of DDGS in the diet can be overcome by withdrawing the DDGS from the diet during the final 4 to 6 weeks of the finishing period. A 4-week withdrawal produced acceptable iodine values (mean of backfat and belly fat of approximately 70). The addition of a hard fat such as beef tallow to the diet, however, was unsuccessful as a means of improving belly firmness and elevated iodine values of pigs fed DDGS at high dietary levels. Under the conditions of this study, the softer bellies, increased polyunsaturated fatty acids, and higher iodine values did not negatively impact bacon processing or eating quality of bacon or loin chops in pigs fed a high level of DDGS.