Detecting the risk of dehydration in cattle is a way to preserve animal welfare that prevents loss of life in extreme cases. This article presents a technological ecosystem based on precision livestock farming, an extension of the E-SED ecosystem. Its components, hardware and software, consist of smart Edge Computing devices connected to the Cloud Computing infrastructure and Internet of Things. These devices are necessary to put into operation an application based on an Expert System for the Detection of Dehydration Risk model. A preselection of the data to be sent to the Cloud is considered in order to reduce network traffic. It is particularly proposed for a forested rural area called Monte in central Argentina dedicated to extensive livestock farming.