Effect of amino acid nutrition level in pregnant dry cows on calf viability

The objective of the study is to determine the effect of introducing deficient amino acids (methionine, lysine) into the diet of late-pregnant cows on the physiological state, the level of immunity development through colostrum (colostral), and changes in non-specific resistance in calves during the first period of life. The study was conducted in the production conditions of the Agro-Soyuz farm in the Kabardino-Balkarian Republic during the winter period. The paper presents the results of a scientific and industrial experiment to determine the degree of influence of methionine and lysine deficiency in the diet of pregnant cows in the last month of pregnancy. Analysis of the winter diet of late-pregnant cows showed that the me-thionine deficiency from the norm according to A.P. Kalashnikov is 18.5 g (42 %), and for lysine, 50 g (57 %). Insufficient amino acid nutrition of pregnant cows reduces the protein content in colostrum from 27.3 to 16.7 %. Normalizing the diet for methionine and lysine increases the immunoglobulin content by 2.4 times, including IgG, IgM, and IgA classes – by 2.3, 3.6, and 2.8 times, respectively. This ensured an increase in the immunoglobulin concentration in the blood serum of calves in the experimental group al-ready 6 hours after the first feeding by 10.18 mg/ml, or 143.8 %, and after 24 hours – by 13.95 mg/ml, or 76.6 %. Higher concentrations of immunoglobulins in the serum of calves in the experimental group en-sured a lower incidence of disease and a high survival rate in the first month of life. 100 % of calves in the control group recovered from the disease, of which two died. One calf in the experimental group suffered from mild diarrhea. Subsequently, average daily weight gains were 18.9–20.5 % higher in calves in the experimental group. Normalizing the methionine and lysine levels in the diet of pregnant cows subsequent-ly increases the immunoglobulin content in the cows' colostrum, which ensures high levels of immunity and survival in the first month of life.