Eye Surface Temperature as a Potential Indicator of Physical Fitness in Ranch Horses.
Authors: Esteves Trindade Pedro Henrique, de Camargo Ferraz Guilherme, Pereira Lima Maria Lúcia, Negrão João Alberto, Paranhos da Costa Mateus J R
Journal: Journal of equine veterinary science
Summary
# Eye Surface Temperature as a Fitness Indicator in Ranch Horses Infrared thermography of the eye offers a non-invasive method for assessing physical fitness in working horses, with researchers examining 16 ranch horses across multiple physiological markers before and after a standard working day. Alongside eye surface temperature (ESTmax), the team measured respiratory rate, heart rate during exercise, creatine kinase (CK) activity, serum protein, cortisol and lactate concentrations, documenting work duration, velocity and distance travelled under varying environmental conditions. A moderate positive correlation emerged between changes in ESTmax and CK activity (rs = 0.56), with cluster analysis dividing the cohort into two fitness groups that differed significantly in both measures—notably, the lower-fitness group displayed CK elevations above 350 U/L, suggesting exercise-induced muscle damage. Whilst hydration status did not affect eye temperature readings, the findings indicate ESTmax could serve as a practical field tool to predict muscle stress responses without requiring blood sampling or laboratory facilities. This approach warrants validation across larger populations and diverse work intensities before adoption as a standard fitness assessment, but presents genuine potential for coaches and practitioners seeking objective, real-time indicators of training load and recovery in ranch and performance horses.
Read the full abstract on PubMed
Practical Takeaways
- •Infrared thermography of eye surface temperature may offer a quick, non-invasive field method to assess physical fitness and muscle stress in working ranch horses without blood sampling
- •Horses clustered as HIGH fitness showed elevated CK levels (>350 U/L), suggesting eye temperature correlates with exercise-induced muscle damage—useful for monitoring workload appropriateness
- •This preliminary technique requires validation in larger studies before routine adoption, but could become a practical tool for ranch managers to identify horses needing recovery time or reduced work intensity
Key Findings
- •Maximum eye surface temperature (ESTmax) increased after a working day in all 16 ranch horses studied
- •DIF-CK and DIF-ESTmax were positively correlated (rs = 0.56, P < .05), suggesting eye temperature reflects muscle damage
- •Cluster analysis identified two fitness groups with statistically different DIF-ESTmax and DIF-CK values; HIGH fitness horses showed CK > 350 U/L indicating muscle damage
- •ESTmax showed potential as a non-invasive predictor of creatine kinase changes and physical fitness status, though effectiveness requires confirmation in future studies