Increasing the productivity and quality of the final dairy products of cows is a key factor for the provision of high-quality dairy products and preserving human health in the context of the sanctions policy of foreign countries. The aim of our research was to study the different ratio of lysine and methionine and its effect on milk productivity and quality in the first months of lactation of the Holstein breed of cows. In 2021–2022, two groups of cows with eight animals in each were formed on the basis of the integrated agricultural production center “Plemzavod Maysky” in Vologodsky District of the Vologda Region. The animals of the experimental group received a diet calculated using the CNCPS model and balanced for the content of lysine – 6.8% and methionine – 2.6% of the metabolizable protein. The rations for cows contained 16.2% crude protein in the control and 15.6% in the experimental group of cows, the metabolizable protein was at the same level (11.1–11.2%) and were compiled when calculating the milk productivity of 40.0 kg of milk per day. The daily yield of 4% fat content in the experimental group prevailed by 2.0 kg, and in the natural – by 1.3 kg, respectively. At the same time, the gross yield of fat and raw protein with milk increased by 6.1 and 0.5 kg, respectively, over 60 days of lactation. The ratio of lysine and methionine in the diet at the level of 2.71 to 1.00 contributes to a significant decrease in the lactose content in cow milk by 0.21% compared with the control (p < 0.05). Probably, the decrease in lactose levels is due to a decrease in glucose synthesis in the digestive tract due to their high consumption for the synthesis of microbial protein and increased synthesis of volatile fatty acids, necessary substrates for the synthesis of milk fat
Keywords
productivity, milk, amino acids, Amino acids, metabolic protein, characteristics of cow milk