Effect of fearfulness and cortisol reactivity to stress on the spatial learning performance in mountain primitive horses

Abstract

This study aimed to determine whether the level of fearfulness and cortisol reactivity influenced spatial learning performance in primitive mountain Hucul horses. The Huculs had to overcome particularly difficult, sometimes dangerous conditions to survive over centuries. We hypothesized that they were familiar with danger and should learn easily. The study involved 22 mares. They were divided into groups of different fearfulness levels according to behavioral score and cortisol concentration increase in the saliva, both of which were determined in a test of a novel object. In the next step, the mares were subjected to a spatial learning test in a maze with food reward at the end, conducted in two trials, on consecutive days. Their spatial learning performance was assessed with an error score and time taken to complete the maze. The study found that both the level of fearfulness and cortisol concentration increase varied in the mares. The spatial learning performance of mares that had low, medium and high levels of fearfulness and cortisol increase was similar within a trial, although animals displaying a medium fearfulness level or moderate cortisol change achieved better results in the second trial than in the first trial. These results indicate a weak influence of the fearfulness and cortisol reactivity on spatial learning performance in Huculs which may suggest an effect of the origin and historical environment of the breed.