Enhancing life-long resistance to nematode parasites: possibilities from nutritional supplementation of recently weaned sheep

Susceptibility to infection from gastrointestinal nematode parasites in sheep is most pronounced in young animals which remain susceptible to infection well into the second year of life. The reasons for this prolonged susceptibility to nematode infection are poorly understood but may be a consequence of a number of factors such as immunological incompetence, insufficient antigenic stimulation, interrupted infection and inadequate nutrient supply. The net result of the prolonged susceptibility is greater reliance on anthelmintic control which has led to widespread anthelmintic resistance.