A Non-Invasive System for Remotely Monitoring Heart Rate in Free-Ranging Ungulates
Abstract:A new, external non-invasive telemetric heart rate (HR) monitoring system was evaluated on eight wapiti, Cervus elaphus canadensis, yearlings in July and August 1996. The assembly consisted of a leather girth strap, onto which a HR transmitter and a customized carriage bolt electrode system were fixed. To prevent the girth strap from rotating on the animal, it was secured with adjustable nylon straps extending anteriorly between the forelegs up to an adjustable neck collar. In preliminary testing, audible tones were received during 99 per cent (n = 902) of the 15s intervals when the animals were active, but only during 33 per cent (n = 156) when they were bedded. After 2 weeks, the equipment remained functional (and was removed); the effective signal range was consistently beyond 500m. This HR monitoring system is easy to attach externally, obviates complications from surgery, and provides coverage over an extended range.
The monitoring system offers a reliable, humane and inexpensive method for short-term measurement of HR in captive or wild ungulates. Further tests may reveal a potential for long-term application. The ability to measure physiological responses under different management regimes can aid ungulate farmers in selecting optimal herd sizes and social structures for their animals; and in developing superior housing, enclosure designs, handling and transport methods. This improves the animals' welfare, and ultimately leads to an increase in animal growth and herd productivity. In addition, information about heart rates can help wildlife managers to improve their management strategies, by gaining an understanding of the energy expenditure associated with various activities and environmental influences.