Studies on Bovine Gastro-Intestinal Parasites. XIII. Species Diagnosis of Nematode Infections by Egg Characteristics

Abstract

of anthelmintics on the different species. Species diagnosis as a result of studying the larvae has the disadvantage of being time consuming because of culturing the eggs and the necessary careful microscopic examination of the larvae. Consequently we turned to the egg characteristics to determine if it were possible to differentiate the species in this manner. Many of the gastro-intestinal parasites of cattle, such as tapeworms, liver flukes, whipworms, Strongyloides, and Nematodirus have very characteristic ova, but the eggs of the nematodes belonging to the genera Cooperia, Ostertagia, Trichostrongylus, Haemonchus, Oesophagostomum, and Bunostomum have a much closer resemblance to each other. After observing the eggs of cattle parasites over a period of several years in both natural and pure experimental infections we came to divide the eggs of these genera into four groups but lacked accurate measurements and other details for differentiation.