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Scientific context and objectives

Gastrointestinal nematodes are responsible for one of the main pathologies observed in grazing animals. All small ruminants grazing on grass are exposed to parasitism. For decades, animals have been managed using synthetic dewormers, called anthelmintics, in a systematic way, even when the animal was not infected. As a result, these parasites have developed strong resistance to treatment. The situation is so problematic that in some farms, all known molecules are ineffective. To prolong the use of anthelmintics and avoid a therapeutic dead end, it is urgent to develop more integrated management strategies, limiting the use of chemical molecules to extreme cases.

This thesis takes place in this context of seeking alternatives to the use of anthelmintic molecules. In particular, the originality of this thesis is to promote the use of animal behavior as a means of ensuring animal health. Indeed, small ruminants, like many other species, use olfaction to prevent dangers, whether by recognizing predator odors or identifying potential disease vectors or toxic substances. In this context, the thesis will investigate an original strategy around animal behavior and the primary sense of olfaction. This sense guides vital activities such as food searching, predator avoidance, and communication between individuals, and can be mobilized for avoiding grazed areas containing feces.

Several studies have been conducted on this topic, demonstrating the ability of small ruminants to avoid grazing on areas contaminated by feces, if given the choice. This avoidance capacity is particularly interesting in our context, as it helps break the natural cycle of animal infestation by limiting larval ingestion. One study even suggests a genetic basis for the avoidance capacity in sheep, opening the door to selection schemes.

The objective of this thesis is to characterize goats’ fecal avoidance using standardized behavioral tests. This will involve highlighting any individual variation in avoidance capacity, as well as a genetic basis for this behavior. These works will contribute to discussing the use of behavior in the perspective of integrated parasite management.

Expected candidate

The thesis has a strong experimental component, involving working with farm animals, especially for setting up behavioral tests. Analyzing the results will require basic skills in descriptive statistics and genetics. Serious candidates with skills in animal experimentation and the ability to integrate into a team are expected. Skills in ethology would be appreciated.

The thesis work will take place in Guadeloupe, at the Duclos site in Petit-Bourg. The hosting unit is highly interdisciplinary and is committed to developing agro-ecological farming solutions in challenging environments, particularly climatic ones. This thesis, which prepares for research careers, will develop skills in animal experimentation, behavior, parasitism, genetics, and methods for automated behavior monitoring.

How to apply

Send a CV and cover letter to mathieu.bonneau@inrae.fr