The research was carried out at an enterprise in the Sverdlovsk region. Two groups of black-motley cows were formed: the first including cows of free stall housing with a robotic milking system; the second having tied cows that were milked into the milk pipeline. It was found that udder measurements of animals of the first group had greater values than those of the second group. Due to high milk yield of animals for the first lactation in the first group, their milk fat and milk protein content were higher (p < 0.001) than that of cows of the second group, by 36.9 (16.7%) and 37.9 kg (20.5%) respectively. All evaluated hematological, clinical and physiological parameters of animals were within the normal range. In addition, 29.2% of cows in the first group are classified as animals with unstable type of stress resistance, and 8.3% of cows in the second group are classified as animals with low stress resistance. The use of a voluntary milking system for black-and-white cows using a milking robot provides an increase in the intensity of milk flow by 0.2 kg/min with an advantage in the main morphological characteristics of the mammary gland, allows to get higher milk yields on average for 305 days of lactation - by 19.2% (p < 0.001) more and for the period of production use of cows – by 14.3% (p < 0.01). It is necessary to use the level of stress resistance of animals as one of the assessment indicators while selecting cows for milking with high-tech milking machines (milking robots).