Abstract
The study included milk obtained from cows of three native cattle breeds, i.e. White-backed (BG), Polish Red (RP) and Polish Black-and-White (ZB) kept under conventional conditions. The reference group consisted of milk from Polish Holstein-Friesian cows (PHF) maintained in the intensive system and milk from Simmental cows (SM) kept under conventional conditions. The following parameters were determined in 976 samples of milk: content of fat, protein, casein, lactose and solids; acidity (pH value); heat stability; rennet coagulation time; content of α-lactalbumin, β-lactoglobulin, serum albumin, lactoferrin and lysozyme. Additionally, a certain proportion of samples was investigated for fatty acid profile and content of macro- and microelements. Cows of native breeds produced milk of higher nutritional value (higher content of whey proteins and polyunsaturated fatty acids, including CLA) and more suitable for processing as compared to PHF cows. Milk from cows of the Polish Red breed was the most valuable in terms of these parameters, which can be associated with a distinctive phylogenetic origin of this breed. The favourable parameters in regard to the nutritional value and technological suitability of milk obtained from analysed population of cows of 3 breeds included in the programme of genetic resources conservation are therefore an important reason of validity for subsequent implementation of this programme.