The behavioural and physiological responses of dairy heifers to tape-recorded milking facility noise with and without a pre-treatment adaptation phase

Abstract The behavioural and physiological responses of naive dairy heifers to noise that was pre-recorded from a commercial milking facility were examined. Thirty-two dairy heifers were individually moved through an indoor raceway three times daily over a period of 15 days. This period consisted of a pre-treatment, treatment and post-treatment phase, each of 5 days duration. Half (16) of the animals were exposed to the noise stimulus during the treatment phase and half were not exposed to the noise and were used as controls. Heart rate (HR), movement behaviour (transit times and latency to enter the raceway), and animal handling parameters (number of stops and handler interventions required) were recorded throughout the 15 days, and cortisol concentrations were measured on days 6 and 10. Data from the treatment phase were analysed as percentage change from pre-treatment measurements for these variables (excluding cortisol). Overall in the treatment phase, exposure to noise resulted in greater ( p p