Odor and gas emissions and nutrient excretion from pigs fed diets containing dried distillers grains with solubles

Corn dried distillers grains with solubles (DDGS), a by-product of the ethanol industry, has become a common feed ingredient for growing pigs. The nutrient composition of DDGS may contribute to the production of odorous compounds from manure of pigs fed diets containing DDGS due to the concentration of nitrogen (N), sulfur (S), and fiber. A 10-week trial was conducted to determine odor and gas characteristics of swine manure, and N and phosphorus (P) balance of growing-finishing pigs fed diets with and without 20% DDGS. Urine and feces from growing-finishing pigs were collected daily, mixed, and emptied into simulated deep pits (SDP) according to respective dietary treatment. Manure accumulated in the SDP during the 10-week study. Air samples were collected weekly from the headspace above each SDP and analyzed for total reduced sulfur (TRS) and ammonia (NH3). Air samples collected during week 0, 2, 5, and 8 were also analyzed for odor concentration using dynamic forced-choice olfactometery with human odor panelists. The head-space concentration of odor, TRS, and NH₃ increased during the 10-week duration of the study. Dietary treatment had no effect on TRS or NH3 emissions, or odor concentration (P ≥ 0.17) over the 10-week trial. Total P excretion was not affected by dietary treatment, but adding 20% DDGS to the diet increased N excretion.