Researcher Phung LeDinh, to be getting his PhD at the Animal Sciences Group (ASG) at Wageningen University, the Netherlands at October 25th, also claims that reducing the level of sulphur is possible without losing out on technical results.
The research shows that by adapting the feed smells could be lowered by 80%. In addition, also ammonia emission could be reduced.
Controlling the amount of sulphur is a matter of containing the amount of proteins, the research shows, as sulphur is predominantly found in pig feed proteins.
Some raw materials for pig feed are rich in sulphur, like peas or beans. These are not used very well by the pig digestive system. In order to reduce the smell, these components need to be added to the diet in the right, minimal quantities.
The challenge is to feed the pig sufficient levels of proteins to grow and at the same time control the ammonia emission, associated with feeding proteins. This can be done by reducing the raw protein level in the diet and by adding limiting amino acids. Increasing the level of fermentable carbohydrates in the feed also reduces ammonia emission.
However, measures to control the ammonia emission do not automatically reduce the smell of the pig manure and adapting feed rations does not necessarily have to lead to a lower FCR or a slower growth rate, ASG says.