Gastro-intestinal nematodes have been identified as the primary parasites of small ruminants in tropical and sub-tropical areas. Their control has depended upon chemical compounds, but this does not seem to work due to nematode resistance. However, the book has shown that botanical plants and biological control agents could be effective replacements for chemicals when supplemented with the diet of small ruminants. Это и многое другое вы найдете в книге Biological control of gastrointestinal nematodes in sheep (Mawahib Alhag Ali Ahmed,Mark Laing and Ignatius Nsahlai)