The effect of lactation number and lactation stage on milk yield, on the composition and on the microbiological properties of raw cow milk in a Hungarian dairy farm

Abstract

Changes in the composition and hygienic properties of milk affect producer price, so it is essential for the responsible dairy farmer to collect information on changes in these parameters due to various factors. In their study, the authors seek to answer the question whether there is a fluctuation in the daily milk yield of cows and in the composition (fat and protein content) and microbiological properties (somatic cell count, total plate count, coliform and S. aureus count) of raw cow’s milk in primiparous and multiparous cows or at different stages of their lactation. Based on the data of a Hungarian large-scale dairy farm, it was found that there was no difference in the fat and protein content of the milk, but the daily milk yield was higher in the case of multiparous cows and, compared to the milk of primiparous cows, their milk had a higher somatic cell count and larger amounts of coliform bacteria. The daily milk yield decreased in the successive stages of lactation, but the fat and protein content of the milk increased, which is presumably due to the concentrating effect of the decreasing milk yield. No significant change was observed in the colony count of microorganisms at the different stages of lactation.