Effect of age at training initiation on hoof morphology and lameness in juvenile American Quarter Horses.
Authors: Kawahisa-Piquini Gabriella, Bass Luke D, Pezzanite Lynn M, Moorman Valerie J
Journal: Equine veterinary journal
Summary
# Editorial Summary Three-year-old American Quarter Horses beginning training face significantly higher risk of developing forelimb lameness than their two-year-old counterparts—84.6% versus 48.3% respectively—according to this prospective cohort investigation tracking 42 juvenile horses over six months. Researchers monitored hoof morphology using radiographic and photographic measurements alongside both subjective and objective lameness assessment (using Lameness Locator®) at months 0, 2, 4, and 6 of training initiation. Notably, lame forelimbs in three-year-olds exhibited significantly narrower feet (11.48 cm versus 12.21 cm), shorter toe length (6.02 cm versus 6.45 cm), and reduced lateral and medial wall heights compared to sound limbs; by contrast, lame hindlimbs showed longer heels (3.74–3.90 cm versus 3.50–3.55 cm), suggesting different biomechanical stress patterns between fore and hind quarters. These findings suggest that practitioners should exercise particular caution when initiating training in older juveniles, with specific attention to identifying narrow feet and reduced wall height in forelimbs as potential predisposing factors to subclinical lameness—though the study's modest sample size and absence of untrained control horses limit the strength of these conclusions and warrant replication in larger cohorts.
Read the full abstract on PubMed
Practical Takeaways
- •3-year-old Quarter Horses are at significantly higher risk for forelimb lameness when entering training compared to 2-year-olds; consider age-appropriate training progression and closer monitoring for older juveniles
- •Narrow feet, short toe length, and reduced wall height are hoof morphology markers associated with forelimb lameness in young horses entering training; farriers should identify these features early and potentially modify shoeing and hoof care strategies
- •Longer heels in lame hindlimbs suggest hoof imbalance may be a contributor to lameness; routine hoof balance assessment and corrective trimming may help reduce subclinical lameness incidence
Key Findings
- •3-year-old Quarter Horses entering training developed lameness more frequently than 2-year-olds overall (84.6% vs 48.3%, p=0.04) and specifically in forelimbs (61.5% vs 27.6%, p=0.05)
- •Lame forelimbs in 3-year-olds were associated with decreased foot width (11.48 cm vs 12.21 cm, p=0.03), shorter toe length (6.02 cm vs 6.45 cm, p=0.03), and reduced lateral and medial wall heights (p=0.03 and p=0.02)
- •Lame hindlimbs showed longer heels compared to sound limbs, particularly in 3-year-olds (3.90 cm vs 3.50 cm, p=0.01)
- •Specific hoof morphology characteristics correlate with subclinical lameness development during early training in juvenile Quarter Horses