Telemetry as a method for measuring the impact of housing conditions on rats' welfare
Various tools have been developed over previous years to study the welfare of laboratory animals. These include preference tests, which are commonly used to evaluate housing environments. Preference tests, however, have some pitfalls: they supply information only on the animals' present
preferences, and they allow the animal the choice only between the options offered. Other methods based upon the collection of clinico-chemical data require handling of the animals, which can be stressful in itself. An alternative may be to use telemetry to measure the changes in physiological
parameters caused by different environmental conditions. The aim of this study was to use telemetry to evaluate the short-term impact of housing conditions on rodents. We monitored heart rate, blood pressure and body temperature in rats kept on three different types of flooring — bedding,
grid floors and plastic floors. The study revealed significant differences in systolic and diastolic blood pressure, heart rate and body temperature between rats housed in the three conditions, indicating that both grid floors and plastic floors are more stressful for the animals than bedding.
The observed differences did not diminish over the two-week observation period. The grid-floor housing induced elevations in blood pressure and heart rate. Blood pressure remained elevated even when the animals were returned to standard bedding, whereas the heart rate declined back to its
original value immediately in response to this shift. This study shows that telemetry is a very effective tool but that it needs integrating with other methods; in addition, a greater understanding of the biological significance of the changes in cardiovascular parameters is required before
the hypothesis that these changes represent an indication of distress can be accepted.