Comparing the Impact of Haemonchus Contortus Infestation on Sheep Breeds Adapted To Pre-Saharan (Ouled Djellal) and Steppe (Rembi) Environments

Abstract

The extension of the resistance of gastrointestinal nematodes to anthelmintics, recently observed for Haemonchus contortus, represents a real problem and makes urgent the search for alternative solutions such as the selection of animals resistant to helminths. All cases of experimental infestations show significant individual variability in egg excretion, clearly discriminating between resistant individuals and susceptible individuals, makes it possible to consider the selection of resistant individuals in the breeds studied. However, the lack of knowledge of the mechanisms of the immune response of sheep to these strongyles remains an obstacle to the development of this selection. The level of excretion of parasite eggs in the faeces represents a relevant indicator for evaluating an animal's resistance to strongyles. This criterion was examined during our study in Algeria in order to evaluate the level of resistance of two sheep breeds to gastrointestinal strongyles, particularly to Haemonchus contortus.