Correlation between Ocular and Rectal Temperature with Intra Ocular Pressure in Horse during Exercise

SIMPLE SUMMARY: The athletic horse has been found to be sensitive to numerous metabolic and physiological changes during physical exercise, making it a stressor which may go on to affect thermal and homeostatic well-being. In the present study we aimed to evaluate some ocular physiological variables (ocular temperature and intraocular pressure) and how they may be correlated to the rectal temperature, which better describes the thermoregulatory system. This study was conducted on 14 healthy horses from the same horse training center. Ocular temperature, intraocular pressure and rectal temperature were evaluated under different experimental conditions (am and pm hours) and before and after a show jumping exercise protocol. Ocular and rectal temperature increased after the exercise as a result of muscle metabolism activation, increasing blood flow in several regions of the body to improve oxygen supply and heat dissipation. On the contrary, intraocular pressure significantly decreased after exercise, probably due to peripheral vasodilatation. Our results showed a correlation between increased body temperatures and IOP variations during exercise. It would be interesting to consider these variables as indicators to determine physiological status of horses during physical exercise. ABSTRACT: The aim of the present study was to investigate the response to physical exercise of some ocular physiological variables (ocular temperature and intraocular pressure) in horses performing a jumping course in the morning (a.m.) or in the afternoon hours (p.m.), before and after the exercise, in correlation with the rectal temperature. Data collection was carried out on 14 clinical healthy Italian saddle horses. All horses were trained from 9:00 to 10:00 a.m. and from 19:00 to 20:00 p.m. according to a specific training program. Ocular temperature (OT), rectal temperature (RT) and intraocular pressure (IOP) were determined. Statistical analysis showed no differences between the results for the left and the right eyes. The application of two-way repeated-measures analysis of variance (ANOVA) showed a statistically significant effect of time (before vs. after) on IOP (p = 0.0001). RT and OT were statistically influenced by time of day and by experimental conditions (a.m. vs. p.m.) (p = 0.0001). Bland–Altman (B-A) testing showed an agreement between the values of RT and OT. Our results showed a correlation between increased body temperatures and IOP variations during exercise, so they can probably be considered indicators of athletic horses’ physical fitness during exercise.