The intensity of physiological and behavioral responses of horses to predator vocalizations

BMC Veterinary Research

Table 1 Cardiac activity parameters with shift towards sympathetic nervous system activity in horses at successive periods of the test of predator vocalization (means ± standard deviations)

Horse pedigree group	Prestimulus period	Stimulus period	Poststimulus period
HR during testing the wolf sound
¾TB	39.0 ± 6.1 ax	50.7 ± 11.1 ay	39.3 ± 0.6 ax
½TB	49.0 ± 6.6 bx	57.0 ± 18.8 ay*	42.5 ± 7.1 ax*
¼TB	43.5 ± 4.1 cx*	52.0 ± 10.2 ay*	41.2 ± 4.0 ax*
HR during testing the leopard sound
¾TB	44.0 ± 7.0 axy	51.2 ± 10.5 ay	39.4 ± 8.8 ax
½TB	57.2 ± 9.6 bx	75.3 ± 12.0 by	56.5 ± 7.5 bx
¼TB	55.0 ± 10.1 bx	67.3 ± 10.7 cy	54.7 ± 6.7 bx
LF during testing the wolf sound
¾TB	3119 ± 886 ax	2909 ± 1403 ax*	2698 ± 763 ax*
½TB	3613 ± 2015 ax	6337 ± 1886 by*	4437 ± 1407 bz*
¼TB	4371 ± 1792 ax	2946 ± 981 ay	3770 ± 1148 cz*
LF during testing the leopard sound
¾TB	3269 ± 2469 ax	6781 ± 2853 ay	1519 ± 638 az
½TB	3514 ± 2781 ax	4338 ± 1999 bx	2467 ± 1010 bx
¼TB	3396 ± 2394 ax	2680 ± 1634 cxy	2196 ± 1168 by

¾TB, ½TB, ¼TB – horse groups with 75%, 50% and 25% Thoroughbred ancestry within the parental and grandparental generations, respectively
HR heart rate, LF low frequency component of the power spectrum
Means marked with different letters significantly differ (according to Tukey’s HSD test) at p < 0.05: a, b, c - in columns (between different horse pedigree groups exposed to the same predator sound); x, y, z - in rows (between the same horse pedigree group at different test periods); *between the same horse pedigree group exposed to different predator sounds in analogical period of the test

ISSN: 1746-6148