Development is the word most used in Sahelian Africa. Yet it remains very ambiguous. Is it to be understood as the result of an equitable mix between endogenous and exogenous factors, a mix between tradition and modernity? Rural people have traditional beliefs, belonging and structure that give meaning to their lives and to ignore them is to undermine the basis on which all collaboration rests. This is why most development assistance programmes fail. It is all the more surprising to note the extent to which popular technical knowledge remains little known by all development operators in the field, who are divided between ignorance and contempt.Taking traditional knowledge into account is an essential factor for the development of livestock farming. Any development intervention in rural areas must take into account the character, values, needs and organisation of the population concerned, and develop development programmes on this basis.