Many studies with different animals have shown that biological rhythms are of great importance for adaptation to environmental conditions, in particular to rhythms of seasonal changes. The purpose of this study was to elucidate whether domestic animals, which have been subjected to profound changes through the effect of artificial selection, retain the adaptive rhythm of seasonal changes. In order to solve this problem an attempt was made by comparing the seasonal rhythm in the structure of the hair coat in aboriginal cattle, which has formed during natural selection, with that in breeds subjected to long‐term artificial selection. It has been shown that in aboriginal cattle (southern Zebu cattle and northernYakutian) the seasonal changes in hair coat (length, density, ratio between fractions) have a clearly expressed rhythm. In herds of stud breeds (black‐spot, Jersey) the rhythmic pattern of seasonal changes in the structure of hair coat is lost. This is associated with considerable decrease in adaptive plasticity, which in an evolutionary aspect has the character of degenerative changes. The large variability in the expressivity of the adaptive rhythms in stud breeds makes it possible to restore the lost biological rhythm of adaptive changes through selection.