Selection tools for the control of gastrointestinal parasitism in small ruminants

Abstract

The sustainability of tropical and extensive temperate farming systems is the key for a balance between the environment (soil, faunaand flora) and animal and plant productions. The restoration or preservation of such a trophic and ecological balance requires theimplementation of innovative techniques. It is vain to avoid constraints in animal rearing and wiser to choose animals for their adaptationsto these constraints. In this context, gastrointestinal strongyle infections are a major constraint in small ruminants, particularlyin the humid tropics. In recent years, the strategy of pest eradication has evolved to a more logical manipulation of hostparasiteequilibrium in grazed systems by implementation of various actions. The genetic resistance of small ruminants to gastrointestinalstrongyle infections is part of this new approach and plays a major role. The objective of this review was to highlight thecontributions of quantitative genetics and genomics to the understanding and exploitation of the differences between individuals forresistance to gastrointestinal strongyle infections. Local breeds are found, in most cases, to be the most resistant and more productivein their environment. Genetic variability exploitable in selection is known in sheep as in goats with a similar genetic control.However, the underlying biological mechanisms are more basic and less efficient in goats. The genomic information accumulates butremains difficult to exploit by professionals.