Measurement of Endurance of Untrained Five-Year-Old and Six-Year-Old Horses Raised in Multi-age Herds on Pasture.
Authors: Brand Anna, Lindner Arno, Gerhards Hartmut, Valenchon Mathilde, Petit Odile
Journal: Journal of equine veterinary science
Summary
# Editorial Summary German researchers investigated whether pasture-reared horses showed measurable improvements in aerobic fitness during their first year of ridden work, comparing five-year-olds assessed twice over twelve months against six-year-olds and trained horses from other countries using standardised exercise testing. The protocol measured two key endurance parameters: v4 (velocity at 4 mmol/L blood lactate) and v180 (velocity at 180 bpm heart rate), derived from incremental treadmill intervals with concurrent blood sampling and heart rate monitoring. Remarkably, neither v4 nor v180 changed significantly in the five-year-olds between September and the following July and September, nor did they differ meaningfully between the five- and six-year-old groups—suggesting that aerobic capacity had plateaued by age five in these extensively managed horses. Foreign trained horses demonstrated substantially higher values for both parameters (P = 0.0001 and P = 0.003 respectively), indicating their superior conditioning. For equine professionals, this finding implies that extended pasture living alone does not develop endurance fitness in late-starting young horses; specific training stimulus is essential to progress beyond baseline capacity, and beginning ridden work at five years does not appear to trigger significant physiological adaptations without targeted conditioning programmes.
Read the full abstract on PubMed
Practical Takeaways
- •Pasture living and natural herd management alone do not improve aerobic endurance capacity beyond age five—structured exercise training is required to develop higher fitness levels in young horses
- •Five and six-year-old horses raised identically show comparable endurance capacity, suggesting developmental plateau occurs by age five when raised without formal training
- •Young untrained horses have significantly lower aerobic capacity than trained horses, which should inform realistic expectations and training timeline planning when starting horses later in life
Key Findings
- •Five-year-old horses raised on pasture showed no significant change in v4 or v180 values over one year of measurement (P > 0.05)
- •No significant difference in endurance variables (v4 and v180) between five-year-old and six-year-old horses raised under identical conditions
- •Foreign horses had significantly higher v4 and v180 values than six-year-old pasture-raised horses (P = 0.0001 and P = 0.003 respectively)
- •Endurance variables appeared consolidated by age five years in pasture-raised horses; additional training beyond pasture management is necessary to improve endurance capacity