Measuring temperature with a chip
| Measuring temperature with a chip An increase in body temperature may be the first sign of infectious disease. So a quick and easy way of measuring the body temperature could provide early warning of a disease outbreak. |  |
Microchips are becoming more widely used for identification purposes. In addition to identifying an animal with a unique number, some microchips contain a temperature sensor. Once the chip has been implanted in the horse (usually midway between the withers and the poll) it provides a simple way to check the temperature.
Chips have the advantage of being quick to read, but does the reading accurately reflect the rectal temperature? Do changes in environmental temperature affect the accuracy? Researchers in Colorado have been investigating.
Tatiana Robinson and her colleagues studied the performance of temperature sensitive microchips in two groups of Welsh pony foals and a group of two-year-old Quarter horses. The ambient temperature ranged from -16°C to 35°C during the study.
They compared the readings from thermal-sensing microchips with measurements of rectal temperature taken with digital thermometers. Scanning each chip was a rapid process, taking only a few seconds. It was not even necessary to touch the horse to get a reading.
The thermal chips gave a wider range of temperatures than did the rectal thermometer.
The ponies had been exposed to a virus infection and so some developed a fever (rectal temperature >38.9°C / 102°F) during the study. How useful were the microchips at detecting ponies with raised temperatures?
The researchers found that the environmental temperature had a strong influence on the accuracy of the thermal microchip readings. When the ambient temperature was less than 15.6°C, the sensor detected only half of the febrile ponies.
On days when the ambient temperature was above 15.6°C, the sensor correctly identified 87% of febrile horses and correctly recognised 94% of the ponies that did not have a raised temperature.
The researchers suggest that the thermal sensor could have a place for screening horses for fever - provided that the environmental temperature is taken into account when interpreting the readings.
It helps if you know what is normal for your horse. Dr Traub-Dargatz advises scanning the chip periodically during various weather conditions when the horse is healthy, so you know how the chip performs in that specific horse or pony.
For more details see:
Comparison of temperature readings from a percutaneous thermal sensing microchip with temperature readings from a digital rectal thermometer in equids.
Tatiana R Robinson, Stephen B Hussey, Ashley E Hill, Carl C Heckendorf, Joe B Stricklin, Josie L Traub-Dargatz.
JAVMA (2008) 233, 613 - 617.
Reproduced with kind permission of Mark Andrews BVM&S CertEP MRCVS
© Copyright Mark Andrews - Equine Science Update 2008
Added on: 08/09/08. Views: 226
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