Published in Scientific Works. Series C. Veterinary Medicine, Vol. LXI
Written by Vijay KUMAR
Exercising equines, especially horses, exhibit significant changes in the physiological responses and several other vital signs. The prominent observable physiological indices are the heart rate (HR), velocity at peak Heart rate (V200), and lactate V[La]. The blood lactate is the biochemical signature of muscular fatigue. Trainings and conditioning schedules have been devised to include the speed at blood lactate levels of 2.0 and 4.0 mM/l. These indices along with recovery of heart rate and blood lactate are important indices for judging the performance of exercising horses. Adaptation to exercise with proper training results in development of cellular tolerance in the exercising muscles and other tissues. With the development of next generation technologies, the analysis of blood and muscle transcriptomes in exercising horses has led to identification of performance genes in race horses. Myostatin (MSTN) genotyping is used to identify and select the horses at early stages for either fast sprint or long distance endurance events. Genes of immune deregulation, mitochondrial respiration, oxidative phosphorylation, tissue repair, tissue remodelling and specific cytokines are among the up regulated genes in the race horses while the most suppressed genes are the ones involved in signal transduction, cell cycle regulation and protein synthesis. Further research is required in the future, to identify the molecular signatures of stress tolerance in horse breeds other than thoroughbreds and race horses, which have evolved and adapted to the climate and utility at specific locations in the world. Such an information would facilitate the horse breeders to devise selection plans in order to improve the exercise and work performance. This would also facilitate diagnosis of the diseases and metabolic disorders that are caused by exercise induced stress.
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