From the 1960s, in developed countries, epidemiological approach widened in veterinary sciences in order to understand and analyze the emergence of "production diseases" in "modern farms" where animal management was compared to industrial process. This approach was linked to "productivism" in livestock farming system. In France, this approach included formerly the understanding of farmers' practices and considered the health disorders as an output of farming system. This theory was known as "ecopathological approach." Since 2000, the main purpose for veterinary sciences seems to be now emerging diseases. In tropical countries, a high intensification of livestock production is expected, especially in periurban areas. This intensification linked to a general better control of main infectious diseases (i.e., Rinderpest, CBPP, anthrax) in such farming system leads to many changes in the farming practices and is associated to the emergence of production diseases as mastitis or infertility in dairy farms, respiratory diseases in pig farms and so on. In those conditions, it is suggested to initiate ecopathological approach in these intensified systems in order to identify the main risk factors due to farmers' practices, environmental conditions, and herd characteristics. The general methodology and some examples in tropical countries (Chad, Brazil, and Senegal) are proposed in the present article.