The effect of stress and exercise on the learning performance of horses

Domestic horses are widely used for physically demanding activities but the effect of exercise on their learning abilities has not been explored. Horses are also frequently exposed to stressors that may affect their learning. Stress and exercise result in the release of glucocorticoids, noradrenaline and other neurotransmitters that can influence learning. It is not currently possible to directly measure concentrations of neurotransmitters in the brains of behaving horses, however the inference of neurobiological processes from peripheral markers have been widely used in studies of human cognition. We assigned 41 horses to either ridden exercise, uncontrollable stress or inactivity and evaluated their acquisition of an industry-style aversive instrumental learning task. Exercised horses achieved the learning criterion in the fewest number of trials compared to the stressed and inactive horses whose performance did not differ. The exercised horses’ salivary cortisol concentrations decreased during learning whereas the concentrations of the other groups increased. Spearman’s correlations revealed that horses with the highest cortisol concentrations required the most trials to reach the criterion. We present novel data that exercise prior to learning may enhance the acquisition of learning in horses. Conversely, activities that expose horses to uncontrollable stressors causing strong cortisol release may impair learning. It is proposed that these effects may be due to the influence of neurotransmitters such as cortisol and noradrenaline on brain regions responsible for learning.

Thermographic Analysis of the Metacarpal and Metatarsal Areas in Jumping Sport Horses and Leisure Horses in Response to Warm-Up Duration

This study aimed to assess the impact of various types of warm-up on the metacarpal and metatarsal surface temperature in jumping sport horses in comparison to leisure horses, which work usually less intensively. Six clinically healthy sport geldings, contestants in showjumping competitions, and six geldings used for leisure riding were included in the study. The experiment was conducted for four consecutive days, during which the horses were warmed up by walking and trotting for various durations. Images were taken with a FLUKE Ti9 thermal imager to determine the resting, post-effort, and recovery temperature of the dorsal and plantar surface of the metacarpus and metatarsus of the four limbs. The obtained data were analysed with SmartView 4.1. software. The increase of measured rectal and surface temperatures was proportional to the warm-up duration. The surface temperature increase in the distal limb parts in jumping sport horses was greater than in horses used for leisure. The plantar surface was also warmer than the dorsal surface of the metacarpal/metatarsal areas, with a forelimb being warmer than a hind limb. Elevated temperatures after warm-up persist for 30 min in the recovery period, especially in jumping sport horses compared to leisure horses. Thus, the warming up effect is achieved earlier and lasts longer in heavily trained horses than in non-performance horses.