What role do instruments play in learning processes? To better understand of the links between knowing (knowledge as a practice) and knowledge (as a stock), we will here explore the hypothesis that instruments are not mere mediators in learning processes, but also act in knowledge and learning activation processes. Through the study of animal qualification activities in genetic selection organizations, we will show how with the approach through the instruments one can go beyond the dichotomy between opposite types of knowledge in speeches, i.e. scientific knowledge seen as a stock, and local knowledge seen as purely tacit, and assimilated to non-instrumented practices. After developing this lens, we will then offer some implications for the management of learning processes through instrumentation.