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. key words: local cattle breeds, milk, nutritional value, technological suitabilityCow's milk is a good raw material for processing, including the manufacture of cheese. Current worldwide production of cheese exceeds 20 million tonnes, including 633,500 tonnes of cheese produced in Poland (FAOSTAT, 2011). The number of cheeses available worldwide is very large and they not only serve to satisfy hunger This work was conducted as part of Ministry of Science and Higher Education project no. NN 311 02 83 34.

Young slaughter cattle are primarily fattened to produce culinary beef. Its final quality is determined by a broad spectrum of factors, including pre-slaughter factors (such as type, breed, sex, feeding system) and post-slaughter factors (such as dressing and meat ageing) (Kołczak, 2008; Litwińczuk and Litwińczuk, 1998; Miciński et al., 2005). It is assumed that the best quality meat is obtained from young animals of the beef type up to 2 years of age.

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The aim of study was to evaluate the chemical composition, including mineral content, in milk of different breeds maintained in organic and traditional farms using intensive (PMR) and traditional feeding systems. The study was carried out on 47 farms in south-eastern Poland. A total of 735 milk samples were analysed, including 263 from cows raised on organic farms, 218 from cows raised on conventional farms using a traditional feeding system, and 254 from cows raised on conventional farms using an intensive feeding system (PMR). All types of farms raised Polish Holstein-Friesian and Simmental cows, and the conventional farms using a traditional feeding system also kept Polish Red and White-Backed cows. The highest (p≤0.01) daily milk yield and content of protein, lactose, dry matter and urea in the milk were obtained from the cows fed in the PMR system. The highest fat content was noted for the milk from the conventional farms using a traditional feeding system. The animals raised in the organic system produced the least milk, with the lowest concentrations of its basic nutrients. The highest mineral content was noted for the milk from the traditional system. The milk from the organic system contained the least Ca, Na, Mg, Zn and Fe, while the milk from the intensive system contained the least Mn. The content of Cu was similar in the milk from the organic and intensive systems and lower (p≤0.01) than in the milk from the traditional system. The results of two-way analysis of variance indicate that the breed of cow significantly influenced milk yield, protein content, protein-to-fat ratio, Ca and Zn concentration (p≤0.01), and the content of dry matter, Fe and Mn in the milk (p≤0.05). .

There are many genes responsible for the appearance of different coat colours, among which the melanocortin 1 receptor gene (MC1R) plays an important role. The aim of the study was to characterize genetic variation in Central European cattle breeds based on polymorphism of the MC1R gene and factors determining their coat colour. The study was conducted on 290 individuals of the following breeds: Polish White-Backed (PW), Lithuanian White-Backed (LW), Polish Red (PR), Lithuanian Red (LR), Carpathian Brown (CB), Ukrainian Grey (UG), and Slovak Pinzgau (SP). Polymorphism at the MC1R gene locus was analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using two restriction enzymes: Cfr10I and SsiI. The proportions of alleles and genotypes in the MC1R locus indicates a strong relationship between polymorphism and the coat colour of cattle: The ED allele proved to be characteristic for the breeds with a white-backed coat (PW and LW), while the dominant allele in the red breeds (PR and LR) was E+. It is noteworthy that coat colour in the SP population was determined only by the recessive e allele, which resulted in the formation of a separate clade in the phylogenetic tree.