Effect of First Long-Term Training on Whole Blood Count and Blood Clotting Parameters in Thoroughbreds.
Authors: Miglio Arianna, Falcinelli Emanuela, Mezzasoma Anna Maria, Cappelli Katia, Mecocci Samanta, Gresele Paolo, Antognoni Maria Teresa
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Young Thoroughbreds undergoing their first formal training experience exhibit significant physiological adaptations in their blood profile, yet these changes appear to normalise with continued conditioning. Researchers monitored 29 untrained 2-year-old racehorses across a four-month sprint training programme, collecting blood samples monthly and analysing full blood counts alongside clotting parameters (prothrombin time, activated partial prothrombin time, thrombin clotting time, fibrinogen and thrombin-antithrombin complexes). Red blood cell indices increased progressively, whilst lymphocytes, eosinophils and platelets all rose significantly; more notably, a hypercoagulable state emerged by day 30 of training but resolved to baseline levels by day 90, suggesting the body was mounting a transient clotting response to initial training stress. The findings indicate that early-stage training triggers compensatory haematological responses—likely preparing the cardiovascular system for athletic demands—but that consistent conditioning dampens these acute reactions, implying the horse's physiology becomes more stable and efficient as training progresses. For practitioners managing young racehorses, this work supports structured, incremental training programmes as a means to stabilise blood parameters rather than causing prolonged haemostatic disturbance; however, the temporary hypercoagulability window in untrained animals warrants awareness when assessing pre-training baseline values and scheduling intensive early work schedules.
Read the full abstract on PubMed
Practical Takeaways
- •Young racehorses entering first training show transient blood coagulation changes peaking at 1 month; monitor for thrombotic risk during early training phases
- •Continued regular training beyond 90 days normalizes coagulation parameters, suggesting progressive physiological adaptation improves blood safety in athletic horses
- •Complete blood count and clotting profiles may be useful baseline markers when introducing untrained young horses to sprint exercise programs
Key Findings
- •First 4-month training period in 2-year-old Thoroughbreds induced significant increases in red blood cell indexes, lymphocytes, eosinophils, and platelet counts
- •Hypercoagulability state was evident at 30 days of training but returned to baseline after 90 days
- •Regular physical exercise appears to blunt negative effects of acute efforts on hematological and clotting parameters through adaptation to training condition