Miniature data loggers for remote measurement of body temperature in medium-sized rodents

We have investigated the use of miniature temperature data loggers for the recording of abdominal temperature in laboratory animals, using the guinea pig as a model. The data loggers, which are small (16cm(3)), light (20g) and have a battery life of +/-5 years, recorded both the normal abdominal temperature of guinea pigs, and their febrile response to an intramuscular injection of 50µg/kg lipopolysaccharide (E. coli) every 5min for the duration of the experiment (21 days), to a resolution of at least 0.05 degrees C. No calibration shifts or loss of data occurred during the study period. However, despite their small size and versatility, we found that the loggers were suited for use only in guinea pigs with a body mass of approximately 600g or greater. In smaller animals, the loggers caused peritonitis.