The effect of training and competition on the endocrine-metabolic response to stress in trotters.

INTRODUCTION During their agonistic activities, horses would undergo a range of potential psychophysical stressors (i.e., confinement and exposition to new environmental stimuli, restraining or punitive methods, transport, social interaction with conspecifics and human beings, etc.). Even if these welfare problems are well recognized and several studies have been carried out to determine the parameters most involved and indicative of the physiological response to physical exercise in the horse (Seren and Venturini, 1972; Ferlazzo et al, 1984; Li and Chen, 1986; Church et al, 1987; Wilson et al, 1991; MacCarthy et al, 1991), still conflicting data exist. During competition, some additional stressors may exacerbate the physiological stress response related to physical effort in trotters. Psychological and conditioned components of such a response may be highlighted comparing endocrine-metabolic responses due to physical exercise with those elicited by competition.