Abstract
A combined approach in the determination of Haemonchus nematodes from sheep was applied in this trial. Using selected morphological characters 90.2 % females and 84.2 % males of Haemonchus contortus and 9.8 % females and 15.8 % males of Haemonchus placei were identified. Although cluster analysis based on morphological identification clearly separated two Haemonchus species, H. contortus was exclusively detected in all specimens using restriction cleavage of the ITS-2 region with FspBI endonuclease as well as through the sequencing analysis. Because sheep from both farms have never had contact with other ruminants, and the farmers apply only closed flock turnover, we assume that only H. contortus mono-infection occurred on both farms. This opinion is also supported by molecular data. The most striking result of our study was the finding which indicates that the discriminant function is not able to accurately identify Haemonchus males at the species level.