The development of hoof balance and landing preference in the post-natal period

BACKGROUND: Foals can follow the herd within hours of birth, but it has been shown that kinetic gait parameters and static balance still have to mature. However, development of dynamic balance has not been investigated. OBJECTIVES: To objectively quantify landing and pressure pattern dynamics under the hoof during the first half year of life. STUDY DESIGN: Prospective, cohort study performed at a single stud farm. METHODS: Pressure plate measurements at walk and trot from ten Dutch warmblood foals during the first 24 weeks of life were used to quantify toe-heel and medial-lateral hoof balance asymmetry indexes and to determine preferred landing strategy. Concurrently, radiographs of the tarsocrural and femoropatellar joints were taken at 4-6 weeks and after 6 months to check for osteochondrosis. A linear mixed model was used to determine the effects of time point, limb pair (front/hind), side (left/right) and osteochondrosis status of every foal. RESULTS: At 25% of stance duration at walk, front limbs were more loaded in the heel region in weeks 6-20 (P≤0.04), the medial-lateral balance was more to the lateral side from week 6 onwards at both walk and trot (P≤0.04). Landing preference gradually changed in the same directions. Variability in pressure distribution decreased over time. (Subclinical) osteochondrosis did not influence any of the measured parameters. MAIN LIMITATIONS: This study is limited by the relatively small sample size only containing one breed from a single stud farm. CONCLUSIONS: Dynamic hoof balance in new-born foals is more variable and less oriented towards the lateral side of the hoof and to the heel than in mature horses. This pattern changes gradually during the first weeks of life. Knowledge of this process is essential for the clinician when considering interventions in this area in early life