Telemetry is another method for intensive monitoring of an animal's physiological states that provides insights into an animal's level of pain and distress and also generates useful data highlighting and complementing other experimental results. Through the use of telemetry devices, precise monitoring of heart rate, blood pressure, blood flow, body temperature, intraocular pressure, and other physiological variables can be tracked (e.g., Lefcourt, Erez, Varner, Barfield, and Tasch, 1999; Dinslage, McLaren, and Brubaker, 1998). Radio-telemetry techniques can be applied in all commonly used laboratory animal species, from mice to monkeys (Kramer, 2000).
The initial implantation of telemetry transmitters requires surgery and is, therefore, invasive. It has been found that implants of proper size are well tolerated by the animals (Moran, et al., 1998) but there will inevitably be acute adverse sequelae. However, after the initial implantation of the telemetric devices, the method is non-invasive. Animals can move freely, and any increase or decrease in body temperature, heart rate, and blood pressure, etc., can be measured without any handling or manipulation of the animal, thus reducing the animal's stress and the time needed for lab technicians to gather data. Animals who appear during this intensive monitoring to be physiologically compromised from the experimental procedures, i.e., their blood pressure and heart rate indicate severe distress, can be euthanized. Once removed, the telemetric devices may be used again for other animals.
In his paper presented at The HSUS workshop, "Effects of Routine Animal Husbandry and Experimental Procedures on Physiological Parameters of Rats," Dr. Bernie Doerning described some experimental results using telemetry.
The telemetry results found that routine cage cleaning, placement into clean cages, replacement of cages on the rack, and exit of the technician from the room produced an elevation of a range of common physiological parameters above normal for over two hours. In the rats' home cage environment, the effect of routine examinations was slightly less than when they were in a novel environment. Of the group of animals examined in their home environment, heart rates returned to normal after 45 minutes, while the heart rates of the rats examined in the strange environment remained at a higher level for approximately 90 minutes. Similar results were found in related experiments examining changes in physiological parameters during injectable anesthesia versus euthanasia, blood collection, minor surgery, and exsanguination.
To view the full text of Doerning's paper entitled, "Effects of Routine Animal Husbandry and Experimental Procedures on Physiological Parameters of Rats," download the PDF.
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