Tongue-playing and heart rate in calves

Tongue-playing is one of the typical stereotypies of fattening bulls, dairy cows and calves. The purpose of this study was to investigate whether tongue-playing has a de-arousal function by measuring heart rates before, during and after tongue-playing. Five Japanese Black (a beef breed) calves aged 6 months were investigated for 7 h. The periods of inclusive tongue-playing exceeding 20 s, which contained tongue-playing and para tongue-playing, were investigated. As a result, heart rates during inclusive tongue-playing decreased significantly and increased again significantly after that. It is suggested that tongue-playing has a de-arousal function which reduces sympathetic nervous activity.