EFFECT OF THE PRODUCTION SEASON ON NUTRITIONAL VALUE AND TECHNOLOGICAL SUITABILITY OF MILK OBTAINED FROM INTENSIVE (TMR) AND TRADITIONAL FEEDING SYSTEM OF COWS

Abstract

The seasonal variations in milk yield and its chemical composition arise mainly from changes in feeding of the cattle in different seasons of the year. A constant quantity of production and a similar quality of the raw material supply farms, where the feeding of cows is uniform throughout the year (TMR and PMR). The study included 1211 samples of milk obtained in the summer season (663) and in the winter season (548) from cows maintained in traditional and intensive (TMR) system of production. Following parameters were determined: content of fat, protein, casein, lactose and dry matter; acidity (pH value); heat stability; rennet coagulation time; content of α-lactalbumin, β-lactoglobulin, bovine serum albumin, lactoferrin, lysozyme and fatty acid profiles. Cows fed in the TMR system produced significantly (P≤0.01) more milk and of a better chemical composition regardless of the season of production. Milk obtained from cows fed traditionally had the most profitable protein to fat ratio (0,90) and the shortest time of rennet coagulation (3:26 min). It contained significantly (P≤0.01) more whey proteins and had better fatty acid profiles for health. In addition the differences were usually larger in the summer season than in the winter season. It is possible to state that in summer season, when the animals are maintained on the pasture, milk obtained from cows fed traditionally is more suitable for processing and contains more biologically active substances. The daily milk yield and other important quality features of milk, significant interactions between season of production and system of feeding were revealed.