Всероссийский научно-исследовательский институт физиологии, биохимии и питания животных – филиал Федерального государственного бюджетного научного учреждения «Федеральный научный центр животноводства – ВИЖ имени академика Л.К. Эрнста»
ABSTRACT. The aim was to study the technological properties of milk, depending on the breed, the effect of external factors and the carriage of genetic markers on kappa-casein. The economically useful characteristics, composition and technological properties of milk obtained from Simmental cows and their hybrids with Red-and-White Holstein, from pure-bred Simmentals, Kholmogor and native Yakut cattle were studied. The studies were carried out on samples of mixed milk obtained from 10-15 cows of each breed. Characteristics of dairy products (kobi cheese and butter), taking into account genotypes by kappa-casein, were examined on 175 cows of brown Schwitz breed (55 first-calved, 120 cows of 3-5 lactation). Whole blood was used to analyze the genotypes by kappa-casein. Milk of purebred Simmental cows meets the requirements for the preparation of high-quality butter and hard cheese. In the milk of crossed animals with Holstein breed, the concentration of protein and casein decreases by 0.08-0.12% and the duration of its rennet clotting is increased 1.5-1.9 times. With an increase in the proportion of Holstein blood in excess of 75%, the amount of unsaturated fatty acids in butter from the milk of these cows increases by 4.06%, the concentration of volatile and essential fatty acids decreases by 1.37 and 0.59%, and the quality of the finished product worsens. The milk consumption for oil production increases by 6.85-10.5% due to the decrease in the size of fat globules. Milk of crossed animals with a high proportion of Holstein blood more corresponds to the standard of drinking milk and for the production of fermented milk products. When studying the frequency of occurrence of genetic markers in cows of the brown Schwitz breed in different types of marking systems (kappa-casein, prolactin, growth hormone, blood groups, polymorphic proteins-hemoglobin, transferrin, albumin, prealbumin), changes in the allele pool of the herd were observed with increasing number of calving − an increase in the relative number of rare antigens and alleles and a decrease in the number of markers with an average and high frequency of occurrence. The output of the kobi cheese from the milk of the brown Schwitz breed was maximal in the group of animals with the κ-CNBB genotype (1.85 of 10 kg). The minimum fat content (46.2%) and the highest moisture content (58.4%) in the cheese were noted in the group with the κ-CNAA genotype. Animals with the κ-CNAB genotype occupied an intermediate position. Taken into account that the brown Schwitz breed refers to a closed breed of cattle with a specific allele pool, when selecting bulls for the herd, their genetic characteristics must be taken into account.
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