Summary and Implications
Drying method was evaluated based on the impact it had on gross energy and nitrogen concentration of swine feces and urine, and nitrogen in poultry excreta, Twelve individually penned growing pigs were fed one of three diets and 16 pens of 10 growing broilers were fed one of four diets that differed in NDF and CP. Feces, urine, and excreta were collected after diet adaptation and were assumed to vary widely in nutrient composition. Following collection, samples were dried using one of four methods: UD-undried, FD-freeze dried, OD55-oven dried at 55°C for 48 h, or OD100-oven dried at 100°C for 48 h, after which dry matter gross energy, nitrogen, carbon, and sulfur were determined. In swine feces, drying resulted in a loss of GE and S, but among the various drying methods, there was no difference for dry matter, gross energy, nitrogen, carbon and sulfur concentrations. There were no differences in urinary gross energy due to drying or among drying methods; however urinary dry matter was highest for FD compared to OD and higher for OD55 compared to OD100. In poultry excreta, gross energy, nitrogen, and S were reduced by drying, but there were no differences among the drying methods. Regardless of drying method, some loss of gross energy and nitrogen appears to be inevitable, but there is no apparent advantage between freeze drying and oven drying.
Iowa State University
Jacobs, Brandy M.; Patience, John F.; Stalder, Kenneth J.; Dozier, William A. III; and Kerr, Brian J.
"Evaluation of Drying Methods on Nitrogen and Energy
Concentrations in Pig Feces and Urine, and on Poultry Excreta,"
Animal Industry Report:
AS 657, ASL R2653.
Available at: http://lib.dr.iastate.edu/ans_air/vol657/iss1/77