Getting Your Horse’s Therma Zone Just Right

It is believed that some owners may judge their horses’ thermal comfort based on how they themselves feel and may subsequently over-rug, leading to equine discomfort and potentially contributing to obesity. A solution may be to use Orscana, a sensor that measures the temperature and humidity of rug-wearing horses. The study presented below investigated the sensor and found that this device is a useful tool, able to reliably indicate when horses became too hot, even when this could not be manually felt or observed by researchers. Its use could, therefore, optimise rug selection based on a horse’s individual requirements.

 

cheval box couverture

 

 

Validation of the Orscana Sensor to Monitor Equine Thermal Comfort

Bartlett, E.1, Cameron, L.J.1 & Marlin, D.J.2

1University Centre Sparsholt, Winchester, Hampshire, UK.

2David Marlin Consulting

 

There are currently no set guidelines which dictate how owners should rug their horses, likely due to the multitude of individual factors that may influence this decision. Consequently, technological devices are now being produced to remotely monitor the thermal comfort of rug-wearing horses, however, the accuracy and reliability of these devices must first be established to confirm their validity and support future use within the industry.

This study aims to evaluate the ability of the commercially available Orscana sensor to monitor the temperature, humidity, and ‘comfort’ of stabled horses. A sample of mature horses of mixed breed from a college herd (n=6), were studied during November/December. Horses were housed in individual loose boxes, with rugs added consecutively every hour to induce a temperature increase.

Orscana sensors were fitted to each horse according to manufactures guidelines, located in the hollow area above the most cranial aspect of the stifle on the left side. These devices were set to measure under-rug temperature (°C) and humidity (%RH), and to provide a warning when horses became thermally ‘uncomfortable’. iButton® data loggers were secured directly to the horse’s body, located at the hip and wither, and set to take temperature readings every minute. The results provided by the Orscana were compared to iButton® readings, visual observation of behaviour, and a subjective ‘sweat score’ to determine sensor validity. A linear increase in both wither (y = 0.179x + 29.7, R²=0.964, P>0.001) and hip temperature (y = 0.154x + 29.3, R²=0.968, P<0.001) was shown by the iButtons® as rugs were added. The Orscana showed a similar linear temperature increase (y = 0.231x + 24.6, R² = 0.970; P<0.001) although as expected did read ~3°C lower than the iButton® temperatures as these were in direct contact with the horses’ coat. The device is therefore considered suitable for use by the lay horse owner to monitor the temperature of stabled horses.

 

Orscana sensor monitoring the temperature, activity and humidity of four horses

 

Additionally, the same temperature increase was not felt by researcher checks, and no horses were observed to display any signs that may be associated with thermal stress despite both devices indicating that all horses reached temperatures above their suggested thermoneutral zone, thereby suggesting that the use of this sensor may be superior to traditional method of manually ‘feeling’ a horse to determine the suitability of rug load.