Veterinary session

The effects of music, especially those of classical one, are well known in humans and have been studied in detailed. The aim of this work is to investigate whether and how classical music does affect the laboratory animals’ behaviour and in particularly that of the young laboratory rats. In this experiment twelve weaned, experimentally naïve male rats were used in a simplified open-field (OF) test. The rats were exposed to four different musical stimuli. One was an 8-min-long selection of Goldberg Variations BWV 988 by Johann Sebastian Bach and the other the Sonata for two pianos in D major, K 448 by Mozart. The rest two sound stimuli were the same two pieces reproduced at a two times accelerated rhythm and at two octaves higher in pitch (“rodentized human music”).

Before starting the musical sessions, one week adjustment period has been applied: every day we played with the rats, placed them into the future OF-vivarium, in the same order. The experiment took place on 5 different times, every second day. At each occasion only one type of musical piece was presented to all twelve rats, separately. The rats were exposed to each stimulus only once, regularly between 13 and 16 hours.

Each rat spent approximately 8 minutes inside the OF-vivarium and with simultaneous video recording, manual evaluation of behaviour using millimeter-paper was accomplished by two independent observers. The following activities were considered: eating, freezing, moving by the glass walls, crossing the centre, sitting, sitting in corner, sniffing, sleeping, grooming, watching, and watching in standing position. First the basic OF-behaviour was registered for each rat and then the musical stimuli were presented in the following order: Mozart, Bach, Mozart 2 times accelerated and elevated, Bach 2 times accelerated and elevated.

The evaluation of the results showed that the rats unanimously perceived the music, because their basal behaviour changed. Each stimulus had a greater effect on one of the particular activities, for instance the animals spent more time grooming when listening to the 2 times accelerated and elevated Mozart. All musical stimuli, especially the rodentized ones, decreased the kinetic activity of the rats. Overall the animals appeared calmer when listening to music.

Classical music, both in original and in rodentized version, may contribute to the improvement of the laboratory rats’ welfare (3rd “R”: Refinement), but the working out of some details and the selection of the most appropriate music require further research.