A rational technology for cows’ machine milking when tie-up housing should provide for the development of technical equipment that meets the physiological requirements for a dairy cow and ensure complete and safe milking. In this regard, the task of determining and refining certain parameters of the physical-mechanical characteristics of the mammary gland of a cow becomes urgent. When choosing the rational mass of the suspended part of the vacuum milking machine, one should know the pressure transmitted by the teat cup liner to the body of the nipple of the animal when milking, which makes possible to establish the obtained analytical formula. It was found that the higher the deflection of the walls of the stretched teat cup liner, the higher the pressure caused by it on the nipple of the cow’s udder. Analysis of the distribution of diameters and lengths of the nipples of the mammary gland of cows showed that their sizes vary in wide ranges. Elongations of nipples depend nonlinearly on the acting tension, and the values of the elastic modulus and the transverse strain coefficient vary over a wide range