Effect of sound exposure in the ambient environment of Hariana bulls on their plasma concentration of testosterone and cortisol hormones

The present experiment was performed to evaluate the effect of exposure of musical sound signals of 100 and 150 beats per minute (BPM) and intensity below 85 dB, on plasma concentration of cortisol and testosterone hormones of Hariana bulls maintainedat semen biology lab with in the premises of Instructional Livestock Farm Complex (ILFC). The present experiment was carried out for a time period of three and half months (within autumn season) and was accomplished in three phases/conditions. To avoid individual effect of bulls, the same three Hariana bulls were used as experimental animals in all the three phases/conditions. During the first (control) phase of experiment, the bulls were not exposed to any additional source of sound except the normal environmental sound of semen collection site. In second and third phase, bulls were exposed to a musical instrumental sound signal of 100 and 150 BPM with intensity below 85 dB. All the three phases last for a period of one month (four weeks) one after other in continuation, but the third phase was started after a gap of three weeks from the second in order to nullify the persistent effect of sound exposure to bulls during second phase of investigation. The mean values of cortisol and testosterone of Hariana bulls at no exposure, sound signal of 100 and 150 BPM were 35.30±1.82, 37.71±1.82 and 34.87±1.82; and 2.54±0.09, 2.49±0.09 and 2.72±0.09, respectively. In the present study it was observed that the trend of a non significant increase in plasma concentration of testosterone and a non significant decrease in plasma concentration of cortisol as a consequence of this exposure indicated that exposure of a sound signal of 150 BPM with intensity below 85 dB, caused a favorable change in plasma concentration of sex (testosterone) and stress (cortisol) hormones, which might have been associated with better reproductive efficiency of Hariana bulls.