WAIT4 (Welfare: Artificial Intelligence and new Technologies for Tracking Key Indicator Traits in Animals Facing Challenges of the Agro-ecological Transition) project aims at increasing research-based capacities to quantify and characterize animal welfare (AW) in the agro-ecological (AE) perspective and revising farming practices by considering interactions between the animal and its environment. In this perspective, the development of new sensors for assessing the kinetics of physiological variables of interest (Na+, K+, pH) in animals Interstitial Fluid (ISF) by microneedles patch will be a valuable aid for farmers to monitoring AW states and various stressors.