Craniometric indices of adult Trans-Baikal horses

The Trans-Baikal Region is a region with unique landscapes and rich history where the preservation of aboriginal animal breeds adapted to local conditions is of particular importance. The Trans-Baikal horse breed is the result of long-term selection carried out by the local population for many years. The most valuable qualities of these horses are their high adaptability to the conditions of year-round grazing on pasture without permanent buildings and additional feeding. The Trans-Baikal horse plays an important role in maintaining the ecological balance of the region, and therefore craniological studies play an important role in clarifying the course of evolution and variability of animals which results of allow revealing the growth and development of organs during the postnatal period. This paper discusses the research findings on the craniometric indices of the skulls of the Trans-Baikal horses depending on sex and age. The study material included the skulls of stallions, mares and geldings of the Trans-Baikal breed at the age of 7-17 years and 7-10 years. It was found that with age, there was a regular increase of skull size both in mares and stallions, and more intensively in males with the exception of the condylobasal length of the skull. The skulls were boiled and cleared of soft tissues. The following 10 linear measurements were made with a caliper with an accuracy of 0.1 mm: basal length, total length of the skull, greatest facial length, greatest width of the skull, forehead width, minimum width between the orbits, facial width, condylobasal length, lateral length of the skull, and greatest height of the skull; and the relative index - the basal index was also calculated.