Temperature monitoring with microchips

 Horses undertaking strenuous or prolonged exercise in hot and humid environments may produce heat

more quickly than they can lose it, putting them at risk of postexercise exertional heat illness.

 Investigations into heat production and cooling require a way to monitor body temperature. Ideally this should be easy and safe to do in an excitable horse after exercise.

 In practice, reading the rectal temperature with a thermometer is a common starting point – but may not be ideal, particularly if repeated readings in excited horses are required. The “gold standard” for monitoring is to record the central venous temperature (CVT) using a thermocouple introduced into the jugular vein.  

 Temperature sensitive microchips (percutaneous thermal sensing microchip (PTSM)) can be used to measure tissue temperature in a non-invasive manner. But does the site of implantation affect the accuracy?

 Researchers at the School of Agriculture and Food Sciences, and the School of Veterinary Science, at the University of Queensland, investigated the use of PTSMs for monitoring temperature in horses after strenuous exercise.

 Microchips used for identification purposes are generally implanted in the nuchal ligament in the neck. In a preliminary study, the research team found that temperature recorded by a PTSM chip implanted in the nuchal ligament correlated poorly with the CVT during and immediately after exercise. This was probably due to the poor vascular supply of the nuchal ligament compared to other muscles, they suggest.

 The researchers also found poor correlation between rectal temperature and CVT immediately after exercise and for at least 8 min after exercise. Because of this, and for safety reasons, they suggest that rectal temperature should not be used to measure temperature after exercise.

 Of the implantation sites they tested, they found that the most reliable was the pectoral muscles, which closely matched the CVT, followed by the gluteal muscles and the splenius muscle.

 They conclude that PTSMs provide a simple, safe, quick, accurate, and non-invasive way of measuring body temperature of horses immediately after high-speed exercise. They recommend further studies to validate this method under field conditions and in equine athletes working in extreme environments and intensive activity in various equestrian sports.

 

For more details, see:

 The Use of Percutaneous Thermal Sensing Microchips for Body Temperature Measurements in Horses Prior to, during and after Treadmill Exercise

Hyungsuk Kang, Rebeka R Zsoldos, Solomon M Woldeyohannes, John B Gaughan, Albert Sole Guitart 

Animals (Basel) (2020) ; 10(12):E2274.

doi: 10.3390/ani10122274