Repenser Les Systemes Patures Pour Un Controle Integre Des Parasites Gastro-Intestinaux Des Petits Ruminants

Gastrointestinal parasitism represents one of the worst threats to small ruminant farming profitability in the humid tropics. The current control policies, relying mainly on anthelmintics, are increasingly ineffective due to resistances against one, two or even three anthelmintic families. New anthelmintics are not to be expected in the near future, due to increasing economic, legislative and consumer constraints. Researching new control methods requires a comparative analysis of evolution mechanisms acting on parasite host relationship in the wild, and those acting in farm conditions, which have made the parasites over-adapted. Nature can teach us valuable lessons in biology and population dynamics of the parasites, and can help us in tailoring grazing systems to reduce the probability of the encounter of host and parasite, though the return to the natural balance is inconceivable. Moreover, integrated systems of control must apply a combination of methods aimed at reinforcing the host defences (i.e. breeding, vaccination and good feeding level) or decreasing parasite survival (plant or forage with anthelmintic property, nematophagous fungi). Anthelmintic drugs must be used only on animals which are unable to resist the parasites, in order to limit the selective challenge for anthelmintic resistance (i.e. the Famacha© method).