Применение экстерьерной оценки в селекции крупного рогатого скота голштинской породы

Abstract

Abstract. Evaluation of the conformation of cattle is an additional resource for selection. Exterior assessment allows you to level the herd, clarify the breeding value of animals, and identify the direction of breeding work. The purpose of the study is to evaluate the conformation of Holstein cattle in order to improve the herd in the future. Methods. The studies were carried out in 2019 and 2021. The conformation was evaluated in two generations of cows. The evaluation of the herd twice revealed the changes that had taken place. The assessment of the exterior was carried out by several methods: taking measurements; calculation of body indexes; linear assessment of the exterior according to systems A and B, taking into account the shortcomings and defects in the physique of animals [1]. The assessment of the exterior of cows of the first lactation was carried out in accordance with the method of linear assessment. The evaluation period is from 30 to 150 days of lactation. Results. Studies have shown that the conformation of a herd can change rather quickly under the influence of sires with a strong heredity. The studied herd veered towards the delicate body type within one generation. The receipt of tender animals is confirmed by the fact that the cows have become larger, but the width of the sternum (body strength) has not changed much. The bone development index decreased by 0.4 % (P < 0.001) in cows in the 2021 group. The number of deficiencies in cows in 2021 has increased compared to cows in the 2019 group. This confirms the changes that have taken place in the herd. The linear assessment of the exterior of the cows turned out to be the most accurate, as it made it possible to characterize the cows and identify shortcomings in the physique. The scientific novelty of the study lies in the interpretation of the results of the study to develop recommendations that can be used to improve the herd. This will increase the efficiency of the use of cattle in the conditions of industrial milk production.