Study on growth and development of horses from East Bulgarian breed

This study investigated the growth and development of a warmblood sport horses from the East Bulgarian breed, recognized 73 years ago. The study was conducted in the state stud "Kabiuk", Bulgaria. Body measurements were analyzed for 427 foals at age 6 month, one, two, three, and seven years over a 30-year period (1993-2023). Eight body measurements were evaluated, including height at withers, body length, chest girth, and cannon girth. The research aimed to examine the exterior characteristics of modern East Bulgarian horses and assess the influence of sire lineage and family affiliation on these traits. Results showed that by the age of 3 years, the main body measurements were almost identical to those of completely grown animals. The most significant growth occurred between 6 months and 1 year of age, with height at withers increasing by 22.38 cm (16.50% growth intensity). The progeny from the Ladykiller and Gagne Si Peu sire lines demonstrated above-average performance for the four main indicators. Family affiliation analysis revealed that only descendants of Longuza and Likuyushta families had above-average values for height at withers. The tallest horses were offspring of Limnos stallion, followed by Zemen and Calido I. The study provides insights into the growth patterns and genetic influences on conformation in the Eastbulgarian breed, offering valuable information for strategic breeding planning and selection to optimize genetic characteristics. These findings contribute to the ongoing improvement of sport characteristics of the East Bulgarian horse, supporting its prominence in various equestrian disciplines in Bulgaria. Keywords: equine growth, conformation traits, body measurements, equestrian sport genetics, morphometric analysis, East Bulgarian horse, sire line influence