FORMATION OF THE EXTERIOR OF THE COWS OF THE UKRAINIAN BLACK- AND-WHITE DAIRY BREED UNDER THE ABSORPTIVE CROSSOVER

Abstract

During the last decade the world Gene pool of the best cattle breeds is intensively used in Ukraine with the aim to improve productive qualities of animals. In particular, the improvement of dairy cattle includes intensive usage of gene pool of Holstein breed, as its level of milk productivity is the best in the world. The creation of new genotype caused permanent control on the exterior peculiarities of animals and the nature of their connection with productive features. On this basis the aim of our researches was to learn formation of the exterior of Ukrainian Black-and-White dairy breed under the absorptive crossover.
 The researches were conducted at agricultural LCC “Lyshche” of Lutsk region of Volyn oblast on heifers (n = 1164) and full-grown cows (n = 596) of different genotype of Ukrainian Black-and-White dairy breed. There were formed 5 groups of animals: I – cows with Holstein share heredity of 75% and lower, II – with Holstein share heredity 75.1–81.25%, III – with Holstein share heredity 81.26–87.50%, IV – with Holstein share heredity 87.51–93.75% and V – with Holstein share heredity over 93.75%.
 The assessment of exterior was conducted on the measurements of body parts of heifers and full-grown cows on the retrospective analysis. The following measurements were taking into account: height at the withers, breast depth, breast width, chest area behind the shoulder blades, hips width, oblique corpus length and girth of the metacarpus which were used to measure indices of body constitution.
 It is well-known that the exterior of heifers is the criteria of selection of cows into a herd and the assessment if bulls by the type of daughter’s body constitution. It is established that the heifers and cows of the Ukrainian Black-and-White dairy breed under control were quite high (height at the withers – 132.3 and 138.9 cm) with well-developed thorax (breast depth – 72.2 and 81.6, breast width – 46.4 and 54.2, chest area behind the shoulder blades – 191.0 and 201.9 cm). The average length of their corpus was 156.2 and 163.7, hips width – 51.7 and 58.8 and girth of the metacarpus – 18.1 and 19.1 cm.
 The connection between the exterior forms of body constitution and the indices of productivity of animal is especially opening with the use of index estimation of exterior. The usage of body constitution indices gives the opportunity objectively identify development of some parts, their changeability with age, productive and type differences, identify their connection with direction and the level of animals’ productivity in some household environment. The analysis of body constitution indices shows that heifers and full grown cows by the exterior peculiarities belongs to dairy type, were quite harmonious by the body constitution.
 The identifying of measurements of body parts of animals allows to compare their both individual and group peculiarities and to select the best dairy cows. That is why there is the necessity to learn changes of exterior and milk productivity of cows of Ukrainian Black-and-White dairy breed of different genotype. With the increase of Holstein heredity share in the genotype of animals of Ukrainian Black-and-White increased the investigated body measurements (except – breast width and girth metacarpus).
 The heifers had significant (P < 0.05–0.001) decrease in boniness indices, extension, thoracic, hips and chest, chest width and increase of indices of blockiness, sex and conventional corpus girth after the saturation of their Holstein genotype (I). There is a similar tendency of change of body structure indices was also observed in cows, but these changes were mainly unreliable.
 The strength of impact of genotype on the measurements and indices of body structure of both heifers and grown cows was negligible. The heifers’ conditional share of Holstein heredity had the most significant impact on measurements at withers (6.0%) and breast depth (3.6%), and cows – on measurements of oblique corpus length (5.8%), breast girth behind shoulder blades (4.9%) and height at the withers (4.2%) at 0.001 in all cases. The genotype had the most significant influence on bone indices (5.8%), sex (4.0%), breast (3.8%) and hips and breast (3.6%) in heifers’ case, and in full-grown cows’ case – on indexes of conditional volume (II) (5.6%), bones (4.3%) and conditional corpus (I) (3.2%).