The effect of exterior on the length of productive life in high-producing cows
With the aim to estimate body build type of Holstein×Кholmogor cows the authors used 7 standard body measurements and calculated exterior indices. The cows of two herds (n= 126 and 104) were divided according to the sum of type constituent values calculated on the basis of comparison of individual indices with their means. For pelvis-chest and extension indices the type constituent (A) had two gradations: lesser (A=10) and greater than means (A=0) and for compactness, massiveness, bonеness and wide-bodied indices it had three gradation: deviation of individual index from mean value is lesser than 1σ (A=0), in the interval from -1σ to + σ (A=1), and greater than 1σ (A=2). According to value of constituents sum, six body build types were determined: combined, combined massive, milk compact, milk compact massive, milk, milk massive. The 305-day milk yield was greatest in cows of milk body build type: 9506 (+175 kg over means) - 7728 (+208 kg). The cows of this body build type had also the greatest length of productive life and high life milk yield (22865 - 26901 kg). The study of build type heredity revealed that 24% of daughters had the exterior type of their mothers. The data obtained suggest that data of cow's exterior traits may be used with the aim to made a more efficient bull sires selection.