Physiological and behavioral reactions elicited by simulated and real-life visual and acoustic helicopter stimuli in dairy goats

The goats reacted alert to the visual and/or acoustic stimuli that were presented in their room. They raised their heads and turned their ears forward in the direction of the stimuli. There was no statistically reliable rise of the average velocity of moving of the goats in their enclosure and no increase of the duration of moving during presentation of the stimuli. Also there was no increase in heart rate or salivary cortisol concentration during the indoor test sessions. Surprisingly, no physiological and behavioral stress responses were observed during the flyover of a Chinook at 50 m, which produced a peak noise of 110 dB.We conclude that the behavior and physiology of goats are unaffected by brief episodes of intense, adverse visual and acoustic stimulation such as the sight and noise of overflying helicopters. The absence of a physiological stress response and of elevated emotional reactivity of goats subjected to helicopter stimuli is discussed in relation to the design and testing schedule of this study.It has been suggested that flyover of aircrafts and helicopters at low altitude may elicit a stress- and anxiety-related physiological and behavioral reaction in grazing farm animals. Similarly, the noise produced by traffic, tractors, or machinery at short distance and high intensity may impair animal welfare [1].Noise is an unwanted sound, either chronic or intermittent from a variety of sources in the environment [2]. Aircrafts produce significant amounts of sound, the majority of which is produced from turbojet engines, but helicopters are also a source of severe low frequency sound and vibration [3]. Animal species vary greatly in their response to noise, depending on the animal's hearing ability, duration of the noise, type of habitat, time of day and year, the activity the animal is engaged in at the time of exposure, sex and age, level of any previous exposure and whether other physical stresses are present [4]. Despite these variable factors, most re