Effect of pig nutrition on excretion of nitrogen, phosphorus, copper and zinc in manure and on emissions of ammonia, greenhouse gases and odours

Abstract

In order to reduce N, P and trace elements in pig manure, research towards a better agreement between supply and requirement was undertaken in recent years, and the ways to improve the biological availability of these elements in feedstuffs were investigated. Substantial reduction in N excreted by pigs can be achieved by phase feeding combined with a better adjustment of dietary amino acid balance. Feeding pigs with low N diets also allows a reduction of ammonia emission and to some extent the production of malodorous compounds. Phase feeding is also effective in reducing P excretion. However, low digestibility of P in feeds remains the main problem although it is partly alleviated by the supplementation of pig diets with microbial phytase and the use of highly digestible mineral phosphates. In the same way, lowering Cu and Zn dietary supply is obviously an efficient way to reduce pig excretion of Cu and Zn. In a whole farm perspective, improving the efficiency of nutrient utilisation by the animals is an efficient way to reduce the import of nutrients from outside the farm and decrease environmental risks.