Biotelemetry is a useful tool for the simultaneous measurement of several physiological and behavioural parameters in non-restrained, freely moving animals. However, the weight and volume of the implanted intra-abdominal transmitter may cause discomfort. The aim of this study was to assess body weight and behaviour of BALB/c and 129/Sv mice after implantation of an intra-abdominal transmitter. In order to measure more detailed behaviour, the automated behaviour observation analysis system (LABORAS™) was used. During the first days after surgery, body weight and the behaviours of climbing, locomotion and eating were found to decrease in both strains, whereas grooming and immobility increased. These changes were more pronounced in the transmitter animals than in the sham operated animals, however, indicating a temporary impairment in well-being. Within two weeks after surgery, the animals seemed to have fully recovered.
