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

Table 1 Stimuli presented and time points of saliva sampling

	Stimulus	Day	Time	Visual	Acoustic	Salivary cortisol
			7:30			●
			8:50			●
	1	1	9:15	gray air
			9:30			●
	2	1	10:00	helicopter 10%
			10:15			○
	3	1	11:00	tractor 10%
			11:15			○
Visual stimuli	4	1	11:45	helicopter 45%
			12:00			○
			12:50			○
	5	1	13:15	tractor 45%
			13:30			○
	6	1	14:00	helicopter 80%
			14:15			○
	7	1	14:45	gray air
			15:00			○
			15:15			○
			7:30			●
			8:50			●
	8	2	9:15
			9:30			●
	9	2	10:00		helicopter sounds (85 dB; 30 - 1400 Hz)
			10:15			○
	10	2	11:00		tractor sounds (85 dB; 50 - 1200 Hz))
			11:15			○
Acoustic stimuli	11	2	11:45		helicopter sounds (90 dB; 30- 1400 Hz)
			12:00			○
			12:50			○
	12	2	13:15		tractor sounds (90 dB; 50 - 1200 Hz)
			13:30			○
	13	2	14:00		helicopter sounds (95 dB; 30 - 1400 Hz)
			14:15			○
	14	2	14:45
			15:00			○
			15:15			○
			7:30			●
			8:50			●
	15	3	9:15	gray air
			9:30			●
	16	3	10:00	helicopter 10%	helicopter sound (85 dB; 30 - 1400 Hz)
			10:15			○
	17	3	11:00	tractor 10%	tractor sound (85 dB; 50 - 1200 Hz)
			11:15			○
Visual and acoustic stimuli combined	18	3	11:45	helicopter 45%	helicopter sound (90 dB; 30 - 1400 Hz)
			12:00			○
			12:50			○
	19	3	13:15	tractor 45%	tractor sound (90 dB; 50 - 1200 Hz)
			13:30			○
	20	3	14:00	helicopter 80%	helicopter sound (95 dB; 30 - 1400 Hz)
			14:15			○
	21	3	14:45	gray air
			15:00			○
			15:15			○
	22	3	15:35	video Apache helicopter, 40%	peak level 90 dB; 30 - 1400 Hz
			15:50			○
			16:05			○
			12:00			●
	23	6	13:30			●
Flyover Chinook helicopter	24	6	13:45	Flyover Chinook at 75 m	peak level 100 dB; 40 - 600 Hz
			13:55			○
	25	6	14:15	Flyover Chinook at 50 m	peak level 110 dB; 40 - 600 Hz
			14:30			○
			15:00			○

If not indicated otherwise, the visual and acoustic stimuli were those provided by the environment in which the goats were kept (the experimental room on days 1 to 3 of testing, or grassland before, during and after flyover of the Chinook helicopter on day 6 of testing). The normal background noise ranged indoors from 58 dB to 70 dB, and outdoors from 68 dB to 75 dB. For the visual stimuli the percentages indicate the breadth of the tractor or helicopter projection with respect to the breadth of the projection screen. The numbers 1 to 25 (first column) are used in the figures of the results section to indicate which stimulus or combination of stimuli was presented. ●: Baseline cortisol measurements (averaged per day for statistical analysis); ○: Cortisol measurements following the first stimulus presentation of a day (averaged per day for statistical analysis).

ISSN: 1746-6148