Introduction Identification Key Trichostrongylus Cooperia Bovine Ostertagia Ovine Ostertagia Haemonchus Nematodirus Bunostomum Oesophagostomum/Chabertia Strongyloides
If the head shape of the larva is square examine for the presence of refractile bodies at the anterior end of the oesophagus:
Refractile bodies present
Refractile bodies absent