Preliminary Insights into Resting Patterns of Young Thoroughbred Racehorses During Initial Training
Authors: Eric D. P. Sotelo, Meire S. Paulista, Tiago M. Oliveira, R. Baccarin, R. Daros, P. V. Michelotto
Journal: International Journal of Equine Science
Summary
Young racehorses undergoing initial training experience significant changes in their resting behaviour, yet the welfare implications of these shifts remain unclear—a gap this preliminary study begins to address. Researchers used continuous infrared video monitoring to track standing and recumbent postures in five two-year-old Thoroughbreds at two critical phases: arrival at the racetrack and again 3–4 months into advanced training, documenting not only time spent in each position but also frequency of postural changes. Notably, horses spent considerably more time standing and substantially less time in both sternal and lateral recumbency during the advanced training phase (P = 0.003 and P = 0.017–0.049 respectively), with the most pronounced finding being a significant reduction in lateral recumbency events following intense exercise compared to baseline (P = 0.003). Whilst these shifts did not represent overt behavioural disturbance, the reduction in recumbent rest—particularly lateral recumbency, critical for REM sleep—warrants careful interpretation by those working with young stock, as it could reflect adaptive habituation, heightened vigilance in the training environment, or potentially insufficient sleep recovery despite increasing training loads. Further investigation with larger cohorts and polysomnographic data would help distinguish whether trainers should adjust management practices to actively protect sleep architecture in developing racehorses, or whether observed changes represent normal physiological acclimatisation to athletic demands.
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Practical Takeaways
- •Monitor resting behavior changes in young racehorses during early training—increased standing and reduced lying down may indicate adaptation or stress that warrants attention
- •High-intensity exercise acutely reduces lateral recumbency (REM sleep opportunity); ensure adequate recovery time and turnout to support sleep needs during training intensification
- •Track individual resting patterns as a potential welfare indicator in young horses; significant deviations from baseline may signal training stress or health issues requiring intervention
Key Findings
- •Young Thoroughbreds significantly increased standing time (P=0.003) and decreased sternal and lateral recumbency over 3-4 months of training
- •Lateral recumbency frequency was significantly reduced following intense exercise (P=0.003) compared to baseline
- •No day-to-day variation in resting behavior was detected within measurement periods
- •Behavioral changes occurred without major welfare disturbances, but underlying causes (adaptation vs. sleep restriction) remain unclear