Modelling the long-term consequences of implementing hormone-free reproductive management on the sustainability of a dairy sheep farm

•A multi-agent dairy sheep farm simulation model, called REPRIN’OV, is proposed.•REPRIN’OV simulates impacts of hormone-free (HF) reproduction in dairy sheep farms.•Several indicators of farm sustainability are specifically simulated by REPRIN’OV.•HF scenarios were tested for a conventional farm and simulation results analysed.•REPRIN'OV is a tool to design new sustainable HF strategies for dairy sheep farms. Livestock production systems are strongly influenced by societal constraints which induce changes in their overall chain value organization. In dairy sheep farming, practices such as the male effect (ME) supported by new precision tools (heat detector) can be used to stop the use of hormonal treatments (HT) for heat induction and synchronization. However, the effectiveness of these “hormone-free” (HF) methods for managing ewes’ reproduction remains more uncertain than that of HT. Thus, introduction of HF practices in farms currently managed with HT could imply collateral impacts on the overall functioning of the production system and affect its long-term sustainability. In this work, a new multi-agent model (called REPRIN'OV) was designed to simulate consequences of introducing a HF reproduction management on a series of biotechnical, economic and environmental farm performance indicators, including farmer workload. Three reproduction management scenarios were simulated over five consecutive years for the case study of a French dairy sheep farm considered as conventional (i.e. using HT for reproduction management). They were defined as: use of HTs and insemination (HAI); no use of HTs while preserving insemination practice (HFAI); no use of HTs and direct mating only (i.e., no insemination; HFM). Results confirm that implementing HF reproductive management without accompanying it with further changes in farm management, could negatively impact several indicators of the farm sustainability in the medium and long-term. Indeed, the HF scenarios resulted in overall lower farm biotechnical performances (e.g., −4% for the fertility rate; P