Observations on the effect of some measures to prevent gastrointestinal helminth infections in sheep

agentes nocivos animal animal domestique animal nuisible animales animales de carne animales laniferos animales nocivos animals anthelminthique anthelmintics artiodactyla artiodactyle aschelminthes bovidae bovide digestive system diseases diseases domestic animals drugs facteur nuisible ganado helminthe helminths helmintos injurious factors invertebrados invertebrates livestock maladie de l'appareil digestif maladie organique mammals meat animals medicamentos nematode nematodes nematodos noxious animals organic diseases organisme nuisible ovin ovinos pests plagas rumiante ruminant ruminants sheep trichostrongylus vertebrados vertebrates vertebre