Influence des pratiques d'élevage sur l'impact environnemental des systèmes de production porcine
2012
Dourmad , Jean-Yves (INRA , Saint Gilles (France). UMR 1079 Systèmes d'Elevage, Nutrition Animale et Humaine)
Many studies have been conducted in recent years in order to identify farming practices that allow a reduction of the environmental impact of pig production. In this review we focus on the effects of feeding and housing strategies, and manure management. Feeding techniques to reduce nitrogen (N), phosphorus (P), copper (Cu) and zinc (Zn) excretion involves adapting the diet composition to animal's requirements, as well as improving dietary nutrient bio‐availability. The adaptation of animal housing also affects the volume and composition of effluents. Frequent and rapid removal of fresh excreta from the piggery prevents slurry accumulation in the pit under the slatted floor and reduces gaseous emissions. This technique may also facilitate the separation between solid (concentrated in P, Cu and Zn) and liquid (concentrated in N and potassium) fractions, allowing their improved agronomic use as fertilizers. The raising of pigs on straw or sawdust bedding produces solid manure with a high organic N content, which can be a benefit for their agronomic use and/or their export out of the farm. The optimisation of slurry management in pig farms is a complex problem which requires considering many criteria because of the wide range of objectives and solutions. Modelling appears to be an interesting approach to address this question. The first results confirm the interest of the whole system approach making the link between animal feeding, manure management, crop rotation and fertilization, and economy. Investment in research and development is still required in order to propose optimized chains of manure management minimizing gaseous emissions of pollutants (NH3, N2O, CH4...) and preserving nutrients for their use as fertilisers, in systems associating animal and crop productions at different geographical scales. This approach is also very efficient in reducing the environmental impact of pork products as quantified by life cycle assessment.
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