Deep-litter can be an alternative for liquid manure and for improvement of the pig’s welfare. The litter used was sawdust and the performances of the pigs on deep-litter were slightly higher. The author attribute this improvement to better thermal comfort of the animal as they lay on a warm surface rather than directly on concrete. The microorganisms activity of the litter result in an increase in temperature of the material. However, if we set aside the reduction of the manure volume obtained when using the deep-litter, more important losses of nitrogen is done to the atmosphere under the form of NH3 but also N2O and NOx (composting process) than for liquid manure systems.