Extended lactations as a lever for dairy goat herd resilience: an approach based on modelling individual biological trajectories

Starting date : 04/11/2024. Funding: CIFRE (Institut de l'Elevage) 

This thesis, which is part of a larger project (ESCaLL project, CASDAR funding), aims to characterize the biological trajectories of goats in extended lactations. It will study the determinants of their diversity and their role in the resilience of farming systems.

At the animal scale, the objective is to understand biological responses to extended lactation. The thesis project will generate knowledge on coordinated responses in intake, body reserves and milk production in goats in extended lactation. This individual and multivariate approach will help to improve the understanding of causes, timing and level of the milk production rebound observed during extended lactation. It will also quantify the use of energy ingested by goats in extended lactation and the partition between lactation and body reserves. The effects of extended lactation on body reserves can influence the female’s career and longevity. Management of body reserves can affect the ability of a goat to start another lactation.

At the herd scale, the objective is to understand the consequences of different levels of integration of extended lactations in the management strategy and resilience of the system. Extended lactation management generates a diversity of female productive trajectories in the herd. This biological diversity is potentially a resource for system resilience and the thesis project will test this hypothesis.

In addition to the scientific contributions to animal husbandry of farming systems, the knowledge produced will allow the use of extended lactations and to integrate this practice in the best possible way according to the production context of dairy goat farmers and their objectives.

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