Opportunities and strategies to reduce effluent production by pigs

There is increasing concern about the impact that agriculture is having on the environment. As far as the pig industry is concerned, a significant proportion of nutrients that are fed to pigs end up in the effluent. There are two basic options for reducing the amount of effluent produced by pigs. The first is to reduce the oversupply of nutrients being fed, and the second is to improve the efficiency with which nutrients are utilized by the animal. In this paper some of the strategies that currently exist for reducing the output of N and P in piggery waste are discussed. Particular emphasis is given to the use of computer modelling techniques to calculate the nutrient requirement of pigs at various stages of growth, and feeding strategies that make greater use of synthetic amino acids and enzymes