The effect of subclinical mastitis on qualitative composition of milk

A complex of mammological studies was carried out in experimental farms of the Vladimir region. Lactating cows underwent an express diagnosis of the health of the udder with the California mastitis test, and based on the result obtained, three groups of animals were formed, 20 animals each. The animals of the first group had a questionable reaction to the California express method; animals the second - weakly positive; the third group included blood with negative reaction to tests (control). In studies of milk from cows with suspected udder inflammation, a decrease in dry matter content and a change in the quantitative ratio between the constituents of milk were found. The dry matter content in the milk of the cows of the 1st experimental group exceeded this indicator in the milk of the 2nd group of cows by 7.6%; and lagged behind the control by 12.8%. When milk from sick cows was heated, some of the whey proteins were destabilized. The titratable acidity of the milk of the cows of the 1st experimental group was within the limits stipulated by GOST for the prepared milk, while in the cows of the 2nd group it was reduced to 13.22 ± 0.16 ° T, which indicates the onset of the inflammatory process in the mammary gland. When carrying out echographic visualization of the excretory system of the udder of cows, the following features were revealed: with a large volume of the milk cistern, the main type of branching of the excretory system was observed; with medium and small - mixed type; and with mild - loose As a result of the experiment, it can be concluded that animals with a weakly positive reaction to the California Mastitis Test are less productive and they receive milk of lower quality, which is practically not suitable for further use for technological purposes. However, according to the current Technical Regulations, this milk can correspond to the first or second grade.