Kształtowanie się składu mleka krów rasy czb i cb oraz mieszańców z rasą holsztyńska-fryzyjską i ayrshire

The aim of this study was ascertainment influence of crossing native breeds red-white and black-white holstein-fresian and ayrshire breeds. On the ground of this analysis it's possible to ascertain that milk composition of cross-breds is not to stray from milk composition of red-white and black-white breeds. Unimportant differences in yield lovels was resulted rather from higher production level of crossbreds. In higher production level in black-white breed there was an inclination to decrease of milk contents, whereas in low production level in crossbreds the milk contents did not decrease. On the ground of analysis genetics parameters, it's possible to suppose that environmental conditions limited potential production possibilities of cows and to be rubbed away genetic influences.