Аннотация
The study presents the results of research on the influence of the lactation period and calving season on the milk productivity and milk quality of first-calving Simmental cows of Czech selection kept under the conditions of LLP “Aqtogai Milk” in the Pavlodar region. The aim of the study was to identify patterns of changes in milk yield, fat, and protein content during different phases of lactation and in various calving seasons, in order to ensure a stable supply of high-quality milk throughout the year. The research was conducted on 15 first-calving cows kept under identical feeding and housing conditions. Indicators such as milk yield, fat and protein content, as well as the total amount of milk fat and protein produced during lactation, were determined. The chemical composition of milk was analyzed using standard methods.It was found that the average milk yield per lactation was 4,995.4 kg, with an average fat content of 4.10% and protein content of 3.04 %, exceeding the breed standard by 2,845 kg. The highest milk productivity was observed in the third month of lactation (25.4 kg per day), while the highest fat content was recorded during the initial milking phase (4.24 %). The study of the influence of the calving season showed that the highest productivity and economic efficiency were achieved in cows with winter and autumn calving (milk yields of 4,943 and 4,683 kg, revenues of 593,160 and 561,960 tenge, respectively). The lowest results were observed in cows calving in summer (4,501 kg).