Conjugation of Economically Important Traits of Trans-Baikal Stud Horses (Equus caballus)

Conformation scores, body constitution characteristics, and phenotypic correlations between liveweight and body measurements and body condition indices in the Trans-Baikal stud horses were analyzed to improve the breeding efficiency. The surveys were carried out with stud horse sires (n = 7), mares (n = 20), and foals at birth and at the age of 6, 18, and 30 months (n = 48) in the Trans-Baikal krai. The stud horse sires and mares were more efficient in liveweight than the breed standards by 27.2 and 19.3%, respectively. The values for the stallion and mare heights at the withers, oblique body lengths, chest circumferences, and cannon bone circumferences were higher than that for the breed standards by 3.2 and 2.5%, 2.2 and 2.4%, 8.7 and 4.6%, and 7.9 and 8.9%, respectively. Distinct muscle shapes in horses for meat production are typical of the animals. In addition, stocky, large, and long body with strong constitution characterizes the males. The average body weight in the 30-month old foals became 8.0 times greater, while their height at withers, oblique body length, chest circumference, and cannon bone circumference increased by 47.1%, 2.1-fold, 1.9-fold, and 55.6%, respectively. Considering the body condition indices, the Trans-Baikal stallions and mares are characterized as the animals with distinct muscle shapes, ranking closer to carthorse breeds. In stud horse sires, positive relationships between liveweight, cannon bone circumference (r = 0.922), and chest circumference (r = 0.716) were revealed. With respect to the mares, low correlations between the analyzed traits were only observed. Considering the youngstock, positive conjugations of liveweight with all the main body measurements at birth were found. In addition, the closest relationship between liveweight and chest circumference was recorded (r = 0.719).