In the selection of dairy breeds after an exterior the special role is taken to the use of method of linear classification. As determination of pedigree value of bulls is based on classification of daughters at the age of the first lactation of the researches which deal with the plant-breeding-genetic aspects of linear estimation one also limits the array of animals appraised at the same age. Taking into account irrefutable importance of linear estimation, existent united changeability between development of separate descriptive and complex signs with the suckling productivity and age-old changeability of development of the articles of exterior, the research is conducted as for the influence of level of estimation of linear classification of signs at the age of the first lactation on the indexes of the suckling productivity of cows of the subsequent second and third lactations. Reliability of type linear estimation is confirmed if positive correlation during the subsequent use of cows is maintained.

The researchers which were conducted on the total number of livestock of animals of Ukrainian black-and-white and red-and-white dairy breeds witnessed the presence of positive correlations between the estimated signs of exterior and yield of cows with their direction, degree and authenticity changeability depending on the taken into account lactations. At first, at the age of the first lactation the positive coefficients of correlation between exterior signs and size of yield of cows are set which are substantial confirmation in relation to application of this plant-breeding measure as one of constituents in complex determination of pedigree value of animals of dairy cattle in the whole world. The next important element in the aspect of the united changeability of exterior signs of linear estimation with the productivity is the establishment of high enough coefficients of correlations between an estimation after the 100-ball system of four complexes of linear signs with a yield for the first a lactation within the limits of experimental dairy breeds. Within the limits of group signs as evaluated by the first lactation and by the yield of Ukrainian black- and red-and-white dairy breeds, positive connection made was accordingly the following: dairy type (r=0,502 and 0,447), body (r=0,385 and 0,309), hooves (r=0,129 and 0,154), udder (r=0,404 and 0,383).

While researching the question whether existent connection between the estimation of group signs of exterior and size of yield of cows which is got at the age the first lactation and between the same signs and yield for subsequent lactations is saved, it was set that within the limits of the compared groups of animals of both breeds the separate coefficients of correlations which were got at the age of the first lactation repeat themselves in the second one, but with a bit less force but the sufficient level of authenticity.

Correlation between the indexes of linear estimation of group signs of first-calf cows and yield for the third lactation does not repeat the level of analogical connections which were received at the age of the first and second calving, though certain regularity as for their focus is followed with the authenticity confirmation of different level. Considerable part of descriptive signs of exterior is also connected with the amount of yield for the first lactation. This is indicated by the reliable coefficients of correlations. But with the age they go down, and according to the data of the third lactation such connection is almost absents.

The descriptive sex of exterior which correlate with a yield at the age of the first lactation and repeat these copulas with a yield in the second and third ones refer to the signs typical for the animals of dairy type which is the reliable indexes of cow milking capacity. They include: stature, chest width, body depth, angularity, rump width, rear legs rear view, fore udder attachment and rear udder height, central ligament.

Thus, the reliable level of cross-correlation between the estimation of group signs of linear classification at the age of the first lactation and yield for the followings second and third ones testifies the efficiency of selection of suckling cattle  appraised according with an exterior type. The level of the united changeability of part of descriptive signs of exterior and the yield of first-calf cows does not repeat itself in combination of indexes of the same estimation with a yield at the age of the second and third lactations. That is explained by the natural unevenness of age-old changeability of development of the build under the influence of genotype and paratype factors.

Key words: black-and-white dairy breed, red-and-white dairy breed, exterior, correlation, yield of milk, lactation.