Precision Dairy Farming technology has mostly focused on tools to improve cow care, but new tools are available to improve the care of pre-wean calves and heifers. These technologies apply real-time monitoring to measure individual animal data and detect a deviation from normal. On-farm validation of new technologies remains important for successful deployment of new technologies within commercial farms to understand how the technology can improve dairy calf welfare, performance, and health. The objective is to validate if an indwelling rumen temperature monitoring system improves farm management and illness detection. This study used an indwelling rumen temperature monitoring device with a herd management user interface from ST Farmfit. The herd management interface not only provided the interface for users to visually monitor the temperature recorded by the rumen bolus, it also provided health alerts from 4 consecutive high fevers recordings, and the ability to record animal health events and treatments. Multiple factors exist that are critical in determining if a technology is valuable to farm management. One value includes determining if the technology can be validated against a gold standard which for calf temperature monitoring is rectal temperature. Not only is a rectal temperature above the fever threshold of 39.5°C trigger a health alert but does rectal temperature correlate to indwelling ruminal bolus temperature. Our validation explored both of these factors to determine if this system identifies fevers that truly exist and if it can be correlated to rectal temperature. Another important factor is the ability of the technology to positively identify fever in calves. Utilizing an on-farm study, we assed if the technology positively predicted fever and if the farms current management was improved with the use of indwelling rumen temperature monitoring. One of the farm managers in the study commented early in the study that the herd management app helped identify ill calves but more importantly improved treatment protocol compliance. The herd management app provided notifications each time a calf needed retreated. To completely assess this technology, we surveyed farmers' experience with the farm management app, how well the technology identified fever, and if it correlated to rectal temperature. Our paper will outline the survey results and results comparing the bolus to human identified sickness through visual assessment by the farm manager. This technology has the potential to calf care and animal welfare.