Milk composition as an element of herd health control

Abstract. Purpose of research is monitoring the chemical composition of milk, the ratio between fat and protein in milk to determine the risks of morbidity of Holstein cows with acidosis and ketosis. Methods. 5 740 milk samples were studied, of which 1 375 samples were analyzed for 90 days of the first lactation. The analysis was carried out on a Bentley FTS-400 instrument. In the control samples of milk, the following indicators were determined: milk fat, protein, lactose, total solids, solids-not-fat, concentrations of acetone, beta-hydroxy-butyrate. The concentration of beta-hydroxy-butyrate in milk (BHBA (m) and conditionally in blood (BHBA (b) was controlled. The ratio between milk fat and protein was determined by dividing the fat content by the protein content. Cows were divided into groups depending on the ratio: risk of acidosis – less than 1.1, the risk of ketosis is more than 1.5 and the norm is 1.1–1.5. Scientific novelty. For the first time, a comprehensive analysis of the chemical composition of the milk of Holstein cows was carried out to determine its changes with a shift in the ratio between fat and milk protein in the Tyumen region. Results. Monitoring of the chemical composition of cows' milk in the first three months of lactation showed that it changes significantly with a shift in the ratio between fat and protein. There is a significant decrease in total solids, fat and BHBA (b), an increase in solids-not-fat, protein, and in the first month of lactation an increase in lactose at a ratio value of less than 1.1. The ratio is more than 1.5: the content of solids-not-fat, protein, lactose significantly decreases, but the content of total solids, fat and ketone bodies in milk increases, which is characteristic of ketosis.