Morphological, haemato-biochemical and endocrine changes in young Standardbreds with ‘maladaptation’ to early training.

This research focused on the physical, biochemical, and hormone changes in young Standardbred horses that showed signs of poor adaptation to their early training. The study wanted to find indicators of early maladaptation that could be identified under conditions normally encountered on the racecourse.

Research Methods and Participants

• The research involved 65 two-year-old Standardbred horses during their initial three months of training in five different training centers. The horses were monitored for various metrics on a monthly basis which include:
• Morphological variables – This includes weight, height at the withers (the ridge between the shoulder blades), body condition score, and body composition.
• Haemato-biochemical variables – Information about the blood chemistry of the horse.
• Endocrine levels – These measures involve hormone levels like testosterone, cortisol, thyroid hormones, leptin, IGF1, and prolactin.
• The researchers also looked into the feeding levels and the training program for the horses.

Research Findings

• At the end of the three months, based on abnormal weight loss, 14 horses were suspected of maladapting to the training and they were classified as ‘MT group’. The remaining were labeled as ‘control group’.
• The MT group displayed a significantly higher weight loss, more specifically, a higher loss of fat mass and body condition score compared to the control group.
• The MT group also showed higher GGT (an enzyme in the blood) and white cell counts (indicative of a potential immune response) and lower red cell counts (that carry oxygen) than the control group.
• The level of T4 (a specific thyroid hormone) was notably lower in the MT group than in the control group.

Conclusion

• The research concluded that some young horses show signs of energy imbalance as well as changes in their blood biochemistry and hormone levels when they are not adapting well to their early training.
• The indicators identified in this study could prove useful in the early identification of training maladaptation, thus aiding in the care and management of young horses in training. This could potentially prevent chronic fatigue, improve the horse’s welfare, and the long-term performance of the racehorses.