Effects of Feeding Distillers Dried Grains with Solubles to Finishing Swine on Animal Performance, Manure Characteristics, and Odorous Emissions

and Implications Seventy-two finishing pigs were used to evaluate the effects of distillers dried grains with solubles (DDGS) on pig performance, manure characteristics, and odorous emissions. Three diets containing 0, 5, and 10% DDGS were fed during six 4-wk feeding periods. Week 1 served as a dietary adjustment period. Animals were housed in two feeding rooms (six pigs per room) with one treatment per room. A new group of animals (average initial Body Weight = 85.8 kg) was used for each feeding period. Diets were replicated four times. Rooms were equipped with individual shallow manure storage pits that were cleaned once weekly (day 7). On day 4 and 7 of each week manure pit samples and air samples in 10-liter Tedlar bags for olfactometry analysis were collected from each room. Dynamic dilution triangular forced-choice olfactometry was conducted using the Ac’scent International Olfactometer (St. Croix Sensory, Stillwater, MN) located in the Iowa State University Engineering Department of Agricultural and Biosystems. No differences in animal performance, as measured by average daily gain and feed efficiency, were observed (P > .05). Greater feed disappearance (P < .10) was observed from animals fed 10% DDGS. A nonsignificant trend of increasing odor, in terms of odor dilution threshold, was observed with increasing dietary concentration of DDGS (P = .16). A nonsignificant trend for increasing odor with increasing DDGS demonstrates the potential for diet formulation to improve odor. This increase in odor was likely due to the increased levels of dietary crude protein, amino acids, and elemental sulfur that were observed with increasing DDGS in the diets. Diet manipulation as a means to reduce odor needs to be investigated further.