Longitudinal development of equine forelimb conformation from birth to weaning in three different horse breeds.

This study investigates the changes in the physical form of the front legs of young horses, from their birth to weaning, across three types of horse breeds. The objective was to better understand the unique conformational variances in the early months of growth in horses.

Methodology of the Study

• This study consisted of multiple observations of young horses from birth to the age of six months, focusing on the physical make-up of the carpus (wrist), fetlock (ankle), pastern (upper part of horse’s foot) and foot.
• The examined horse breeds included Thoroughbreds, French Trotters and Selle Français (French Warmblood), with a total of 134, 162 and 98 specimens respectively.
• The researchers evaluated these physical aspects separately within one month of birth. The observations continued at around two-month intervals until the foals had reached the weaning stage.

Key Findings of the Study

• The observation found limb deviations -which were mainly angular limb deformities- in 63.6% of the young horses during their first month. Notably, these deformities were diminished by the time of weaning.
• There were consistent occurrences of congenital abnormalities such as carpal valgus (inward bending of the wrist, observed in 42.1% of the foals), fetlock valgus (31.2%), being over-at-the-knee (30.8%) and dropped fetlocks (13%). French Trotters and Thoroughbreds exhibited these abnormalities more than the Selle Français breed.
• Over the course of the study, the form of the carpus and fetlocks changed, becoming less valgus (or inwardly bent). The abnormalities primarily observed at weaning were fetlock valgus, club feet and fetlock varus (outward bending of the ankle).
• The overall observations underscored substantial changes in the carpal, fetlock, and foot conformations from birth to weaning age. Additionally, there were considerable differentiations between the three breeds, mainly during the initial months of life.

Implications of the Study

• The results reveal the need to consider the specific breed when assessing the conformation of a young horse. Different horse breeds may exhibit different conformation peculiarities in their early growth stages and these are important for diagnosis and possible preventive veterinary care.
• This study adds valuable information on the longitudinal development of the forelimb in equines, which was hitherto sparsely available in published research. This information could be instrumental in improving breeding programs and can help in identifying and managing any deformities in young horses during their crucial, early growth stages.