Automatic monitoring of body temperature in dairy cows using implanted sensors

Body temperature is an important aspect of dairy cow health. Measuring body tempera-ture manually is labour-intensive and gives no insight into temperature patterns or ther-moregulation processes. Automated temperature measurement could aid farmers in mon-itoring dairy cow health. This study applied subcutaneous temperature sensors in dairy cows to determine the relationship between sensor temperatures and manually measured body temperatures. At a dairy farm with 185 dairy cows, temperature sensors were im-planted in the necks of 20 dry cows. Sensor temperatures were recorded continuously for eight weeks. Skin temperatures (head and neck), rectal temperatures, and cow health were recorded twice weekly. Outside and barn temperatures were recorded. Average tempera-tures were 35.5±1.2 °C (sensor), 23.5±3.1 °C (head), 30.8±2.6 °C (neck) and 38.4±0.4 °C (rectal). The average outside temperature was 11.9±4.2 °C, and the average barn temper-ature was 19.4±0.8 °C. No relationship was found between sensor temperature and rectal or skin temperature on the head (GEE, P>0.05). Sensor temperature and skin temperature of the neck were positively related (GEE, B=0.13, P=0,000). No relation was found be-tween sensor temperatures and barn or outside temperatures. Skin temperatures were higher when outside temperatures increased (GEE, B=0.27 for neck and 0.55 for head, P=0.000), but there was no relation with barn temperature. Cows showed stable rectal temperatures and regular daily sensor temperature patterns. Anecdotal evidence showed that an irregular and decreasing sensor temperature pattern preceded a high rectal temper-ature (fever) for one ill cow. It is suggested that automatic monitoring of subcutaneous body temperature in cows might be informative of the health status of dairy cows.