Nutritional approaches for prevention and control of gastrointestinal parasites in livestock

Gastrointestinal parasitism has been long considered as a major challenge for the health and the welfare of animals. Parasitism, especially by helminth parasites, impairs health by causing inappetence, diarrhoea, anaemia and, in severe cases, death. In addition to compromising health and welfare, parasitism impairs productivity and results in poor growth and reproductive performance. Livestock are constantly exposed to gastrointestinal parasites through grazing. They eventually acquire immunity to the parasites and successfully regulate them, although their immunity may break down during certain stages of their lives. For the times when animals are susceptible to gastrointestinal parasites, control of parasitism has traditionally depended on the use of anthelmintic drugs. However, occurrence of resistance to anthelmintics is now a worldwide problem. Anthelmintic resistance in gastrointestinal parasites of cattle is an increasing problem, but remains less prevalent than in small ruminants. In addition, there is increased awareness about drug residues that potentially enter the food chain and are detrimental for the environment. Thus, there is an urgent requirement to minimize the regular, preventive use of anthelmintics and combine it with non-chemical means to control the parasitic infection.