The inclusion of inorganic sources of phosphorus can be reduced in diets containing DDGS because the digestibility of phosphorus is greater in all fermented distillers co-products than in corn, but this is not the case for unfermented co-products. The concentration of starch is low in all distillers co-products and the concentration of fiber is relatively high in most co-products. The concentration of energy in the products is less variable than the digestibility of nutrients, but there is variation among the different co-products according to the procedure used to produce them.
If corn DDGS of average or above average quality is used, approximately 30% can be included in diets fed to lactating sows, weanling pigs, and growing-finishing pigs, whereas 50% can be included in diets fed to gestating sows. Inclusion of sorghum DDGS should be limited to 20% in weanling pig diets, but 30% may be included in diets fed to growing-finishing pigs. Corn HP DDG may be included in diets fed to growing-finishing pigs in quantities sufficient to substitute all soybean meal, but there are no data on the inclusion of corn HP DDG in diets fed to sows or weanling pigs. Corn germ can be included in diets fed to growing-finishing pigs in concentrations of at least 10%.
Carcass composition and palatability is not influenced by the inclusion of DDGS, HP DDG, or corn germ in diets fed to growing-finishing pigs. However, belly firmness is reduced and fat iodine values are increased by the inclusion of DDGS and HP DDG in these diets. It may therefore, be necessary to reduce the inclusion of these products in the diets fed during the final 3 to 4 weeks prior to slaughter.
There is some evidence that feeding DDGS diets may enhance gut health of growing pigs, but more research is needed to determine if this response is repeatable. Formulating DDGS-containing diets on a digestible P basis reduces manure P concentration, but due to lower DM digestibility, manure volume is increased in pigs fed diets containing DDGS. Adding DDGS to swine diets seems to have minimal, if any impact on gas and odor emissions from manure, and with the exception of the concentration of P, the chemical composition of manure is not changed if pigs are fed DDGS containing diets. Research is needed to determine practical ways to enhance DM and energy digestibility in DDGS because there is great potential for improving the feeding value of DDGS if DM digestibility can be improved. An improvement in the digestibility of the insoluble fiber fraction is, therefore, needed.
All diets containing distillers co-products should be formulated in such a way that the concentration of crude protein is not greater than in traditional corn soybean meal diets. This requires the use of crystalline sources of amino acids to balance the amino acid profile of the diets.
Glycerin, a co-product from the biodiesel industry, may be included in diets for weanling pigs by at least 6% and in diets for growing-finishing pigs by up to 15%. At these inclusion levels, no change in pig performance or carcass composition will be observed.