COS Jan/03 layout

deal effectively with the increased density of the pork industry in some areas and the increased public concerns regarding nutrient excretion and odour emissions. Successful management of nitrogen and phosphorus is key for sustainable pork production to address these public concerns. For example, nitrogen excretion in the form of ammonia is a concern because of its impact on the work environment inside the barn and also outside the barn for its potential impact on the environment. Swine production has been recognized as a major source of ammonia, which is a noxious gas for humans and animals and contributes to bad odour. The main component of ammonia emission originates from excretion of nitrogen in the form of urea in urine. Faecal nitrogen is less volatile than urinary nitrogen, because faecal nitrogen is bound chemically within proteins or other compounds. Phosphorus is excreted in urine and faeces, and could have a major impact on the environment if not managed properly. Two projects are discussed in this article, and each project was focussed toward specific dietary manipulations to alter nutrient excretion. Specific actions to improve nutrient digestibility should coincide with a reduced nutrient excretion in the faeces. Over-supplementation of diets with nutrients to ensure maximum pig performance may cause excessive amounts of nutrients excreted in faeces and urine, and pigs should be fed closer to their requirement to reduce nutrient excretion. Finally, the ratio of nitrogen excreted in urine versus faeces can be affected using dietary manipulations. Project 1 investigated two nutritional strategies, dietary particle size reduction and enzyme supplementation, as a means to increase nutrient digestibility and thereby reduce nitrogen and phosphorus excretion. Project 2 investigated reducing dietary protein and fermentable fibre as means to alter nitrogen excretion.