Linear score evaluation of conformation of Holsteinized Black and White cattle and its relationship with milk productivity of cows

Abstract

Currently, modern breeding methods based on objective assessment of the conformation are becoming one of the key factors in creating a balanced, highly productive herd. Linear score evaluation of conformation, which allows moving from a subjective description to a quantitative analysis of traits directly related to economically useful traits, is the most progressive approach to solving this problem, which determines the relevance of this research. The purpose of the research was to carry out the linear score of the conformation of Holsteinized Black and White cattle and to establish its relationship with the milk productivity of cows. The research analyzed the conformation traits of Holsteinized Black and White cows in their first lactation using a score conformation evaluation (systems A and B), and calculated the correlation coefficients between conformation indicators and economically useful traits (milk productivity, reproductive traits) under the conditions of the educational and experimental farm of the State Agrarian University of the Northern Trans-Urals. The research was carried out in 2023–2024 as part of the State Assignment of the Ministry of Agriculture of the Russian Federation. The conformation index (CI) was used for the integral assessment of the herd. The studies revealed that the herd is characterized by high homogeneity and optimal development of conformation traits. However, in first-calf heifers evaluated in 2024, a significant deterioration in udder quality was detected (a decrease in the overall assessment by 3.2 points) and in the strength of the body. The calculated conformation index (246.6–251.4 points) confirmed the high breeding level of the herd. The correlation analysis revealed the absence of strong relationships between most linear traits and productivity in cows during their ’rst lactation, which indicated a curvilinear nature of these relationships, with the optimum corresponding to 5 points according to system A.The udder and limbs were the most problematic traits when optimizing the cow’s conformation.