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Improving the Sustainability of Livestock and Poultry Production in the United States
G.L. Cromwell, J. Grove
Department of Animal and Food Sciences
Certain diets contribute to the excretion of excessive phosphorus, nitrogen, and other nutrient into the environment This project will determine the effectiveness of diet alterations on reducing nutrient excretion into the environment.
2011 Project Description
Manure excreted by swine and poultry is high in phosphorus due to the inability of these animals to degrade the organic (phytate) phosphorus in grains and oilseed meals. Our studies over several years have demonstrated that adding phytase to the diet helps to degrade the phytase and thus increases the bioavailability of feed phosphorus. This allows one to reduce the inorganic phosphorus in the diet which reduces the phosphorus in the manure.
Swine manure is also high in nitrogen which can contribute to aerial ammonia as well as serve as a potential contaminant in ground water. Our studies have shown that reducing dietary protein and supplementing with amino acids, along with using superior dietary ingredients that improve dietary protein utilization will improve body retention of nitrogen (i.e., body protein) and reduce nitrogen excretion in pigs.
Organic forms of trace minerals are claimed to be more bioavailable than inorganic forms, but there are limited data to support this claim. Our studies have shown that the substitution of certain forms of organic minerals may or may not have the potential of reducing trace mineral excretion into the environment.
Studies were also conducted to further assess the relationship of calcium and phosphorus in the diet on the apparent digestibility of these two minerals in pigs.
This past year, we concentrated on studies to evaluate the effects of feeding a diet containing as much as 45% distillers dried grains with solubles (DDGS) to growing-finishing pigs. Belly firmness was decreased due to a higher percentage of unsaturated fatty acids in the fat because of the unsaturated fat in the DDGS. However, eating quality of bacon, Bratwurst sausage, and loin chops were not negatively affected by the feeding of DDGS. In a second series of studies, we removed DDGS during the final stages of the finishing period (2 vs. 4 vs. 6 weeks) and found that DDGS removal partially restored carcass firmness.
Diet manipulation and the use of microbial phytase in swine diets improves phosphorus utilization and reduces phosphorus in the manure. Similarly, the use of superior feed ingredients along with proper amino acid supplementation reduces nitrogen excretion.
The successful use of large amounts of DDGS in swine diets will reduce feed costs without negatively impacting carcass quality or eating quality of pork. This research will help the swine industry to produce more economical and environmentally-friendly diets for pigs.
Cromwell, G.L., M.J. Azain, O. Adeola, S.K. Baidoo, S.D. Carter, T.D. Crenshaw, S.W. Kim, D.C. Mahan, P.S. Miller, and M.C. Shannon. North Central Coordinating Committee on Swine Nutrition. 2011. Corn distillers dried grains with solubles in diets for growing-finishing pigs: A cooperative study. J. Anim. Sci. 89:2801-2811
Stein, H.H., O. Adeloa, G.L. Cromwell, S.W. Kim, D.C. Mahan, and P.S. Miller. 2011. Concentration of dietary calcium supplied by calcium carbonate does not affect the apparent total tract digestibility of calcium, but decreases digestibility of phosphorus digestibility by growing pigs. J. Anim. Sci. 89:2139-2144.