В В Гарт The conjugate variability of milk yield of 1243 first lactation cows with 18 linear exterior traits was analyzed. The research was carried out on the first-calf heifers of a highly productive subpopulation of Holstein cattle with milk yield of over 13000 kg per forage cow. The average productivity of the first-calf heifers for 305 days of lactation was 10093 kg of milk. The relationship between milk yield and linear traits was assessed by calculating the Spearman’s correlation coefficient after adjusting the estimated values of the linear traits to obtain the highest rank of animals with an optimal score. The table of score adjustments is presented. The values of the calculated correlation coefficients for all the studied first-calf heifers ranged from 0.06 to +0.192, which characterizes the relationship as weak. The analysis of correlations in different productivity groups, ranging from 0.109 to +0.191, made it possible to predict possible further changes in the relationship between linear traits and milk yield when selecting for increased milk productivity. It was found that the conjugacy of milk yield with a complex of linear traits ( Rear Udder Width, Fore Udder Length, Rear Udder Height, Stature, Muscularity, Udder Cleft, Teat Length ) was 1.44 or more times higher than the relationship of milk yield with any of the eighteen studied traits separately. The algorithm for creating a complex of linear traits is described. Graphs of milk yield dependence on one and on a complex of linear traits are presented and analyzed. The advantages of predicting the milk yield of the first-calf heifers by a set of linear parameters are shown in comparison with using a single trait of the exterior. The polynomial regression model with high approximation accuracy ( R 2 =0.9538 ) is constructed.
Научная статья 
регрессионная модель