Reducing manure in poultry and pig productions by selection

Abstract

Since they are highly concentrated in some areas in France, poultry and pig production are associated to numerous environmental problems, as a consequence of their manure spreading. Beyond the raw quantity of manure, manure composition, especially in nitrogen, phosphorus, and oligo-elements, is a major source of water and soil pollution. Until now, solutions used to reduce manure quantities were either a posteriori treatments of excreta or reducing waste via modifications of the animals’ diets . Selecting for animals naturally producing fewer excreta was on the contrary not considered, except as a sub-product of selection for an improved efficiency of animals. The aim of this review was thus to give some new insight into alternative ways to reduce manure quantities or to improve their quality by genetic selection. In a first step, indirect selection of traits linked to digestion efficiency or metabolism is planned. In a second step, we present results showing that it is possible to directly select on manure characteristics.