Taking your horse’s temperature is a good thing to be able to do if your horse seems sick and you want to call your veterinarian.  This information, along with pulse and respiration, can help your vet determine if the horse needs to be seen.  However, taking the temperature with a rectal thermometer can be challenging on some horses, especially if they have not been trained to allow it.  You have to find your thermometer and hope it is still working. Then usually you need to find someone to hold your horse as it is really not safe on most horses to take a rectal temperature by yourself.  You also have to make sure the thermometer is touching the rectal mucosa and not stuck in a ball of manure in the rectum because you will not get an accurate reading.  

Because of issues with taking a rectal temperature, a veterinarian in France indicated in The Horse magazine that she had developed a microchip that not only identifies your horse but also provides the temperature.  The microchip is injected in the horse’s, neck like all other microchips, and reads the internal temperature.  Testing on the prototype has revealed that the microchip temperature device is as accurate with less fluctuations than taking a rectal temperature.  While the current system requires you to scan the horse to get the temperature, the researchers are working on a connection to a phone app that would give you the temperature just by going to the app.  Microchips that also determine temperature are already available for other species of animals so it is likely this will be available for horses in the near future.  This will be very beneficial for large farms, especially in disease outbreak situations during which you need to check temperatures on large numbers of horses twice a day.