The Sakhalin population of the small animals is able to reach selection limit and adaptive criterion balance. However, gene frequencies should be in such ratio, when they provide maximum adaptation. In this case selection acts to useful economic characters (productivity, milk quality, somatotype) and not only for adaptation, gene frequencies in locus are determined this characteristic, which should change in case of selection response. Genetic correlation between productivity and features correlated with adaptation was determined for prediction of selection by adaptability in small populations. The value of the inheritability of the signs of milk productivity and signs of adaptation is determined. Small populations have different degrees of adaptation to breeding conditions, do not show heterosis and may reduce adaptation in subsequent generations. Between the first calving age of cows and number of calving was obtained negative correlation coefficient (r = -0,24), calving number and conception rate coefficient was the same (r = -0,23), and between conception rate and economic use duration was positive (r =+0,49). The economic use duration is the indicator which more accurately characterizes population fitness and it closes to adaptation index. This characteristics are connected positive correlation (r = +0,85). Based on the assessment of the degree of adaptation and prediction of population adaptability parameters, work has been done to improve the system of intra-linear selection in the herd.