Qualitative indicators of milk of Simmental and Holstein cows in different seasons of lactation

Background and Aim: Milk producers need to ensure that their cows are producing high-quality, nutritional milk, which is influenced by the breed, age, nutrition, and health status of lactating animals. The aim of this study was to determine the effect of animal breed, season, and milk production on the physicochemical characteristics of milk and predicting the effect of these changes on the composition and quality of milk products. Materials and Methods: In total, 80 milk samples (40 Simmental and 40 Holstein) were analyzed from LLP "Kirova" of Pavlodar region (Simmental breed) and JSC "Astana-Onim" of Akmola region (Holstein breed) in the Republic of Kazakhstan. The physicochemical parameters, including fatty acid (FA) content, were studied. Results: The Simmental cows had the lowest mass fraction of fat in the spring at 3.94% and the highest fat content in the winter at 4.09%, which was the overall highest fat content measured in both breeds (?