Start Date: Oct 17, 2013
End Date: Aug 31, 2014
Diets will be arranged in a 3 × 2 factorial manner, with one factor being diet composition and the second factor being dietary particle size. Two groups of 24 growing gilts approximately 6 months of age, weighing 100 kg will be used to test the objectives described above. While in the metabolism crates, fecal and urine output will be collected twice daily from each pig and added to 24 individual manure storage containers designated for that metabolism crate/pig/diet. Ambient temperature in the metabolism room will be maintained at approximately 21°C, and lighting will be provided continuously. Pigs will be fed twice daily a total amount of feed approximately 3.0% of their body weight, which approximates ad libitum feed intake for this size of pig. Actual feed intake will be determined from feed offered minus feed not consumed. Pigs will have free access to water. Feces and urine collected will be added to the manure storage containers for the manure composition and gaseous emission portion of the experiment. The manure storage containers will be sampled for gas emissions and for manure composition following gas emission analysis on day 46. Manure samples will be collected and measured for chemical and physical properties, foaming analysis, and microbial ecology. Carbon, nitrogen, and sulfur content of diets, feces, urine, and manure will be analyzed by combustion analysis. Manure pH, ammonia, sulfide, and temperature will be measured by ion selective electrodes. Volatile compounds in the manure air from the manure storage tanks will be analyzed by gas chromatography. Manure volume will be obtained by measuring the depth of each manure container at the end of the experiment. At the end of the first trial, each manure tank will be gently stirred and drained to a point where 7.5 cm of "seed" manure will remain in the tank following which a second group of pigs will be fed with their urine and feces (manure) added to the corresponding manure tank. The experiment will be designed as 3 × 2 factorial with the trial utilized as a blocking effect. The individual pig/tank is considered the experimental unit.