Aspects of epidemiology and control of gastrointestinal nematodes in sheep and cattle – Approaches for its sustainability

Gastrointestinal helminthosis in ruminants cause considerable economic losses, with marked impairment of productivity of these animals, especially in poor management systems and poor parasite control programs. Infections caused by these helminths represent an obstacle to the expansion of the sheep industry. Furthermore, high parasite burdens were associated with increased mortality in calves. The recommended methods for the control of gastrointestinal helminths not always have practical applicability. We discuss important epidemiological and control aspects concerning gastrointestinal nematodes in sheep and cattle. Thus, sustainable worm control practices are recommended. Each farm has a specific situation and a management system directed to a specific parasitic infection must be adopted.