Gastrointestinal nematodes in horses in Ontario.
D000818:Animals; D006734:Horse Diseases / Q000453:epidemiology*; D006736:Horses; D007411:Intestinal Diseases, Parasitic / Q000453:epidemiology / Q000662:veterinary*; D009349:Nematode Infections / Q000453:epidemiology / Q000662:veterinary*; D009864:Ontario; D013272:Stomach Diseases / Q000453:epidemiology / Q000662:veterinary*