The Effects of the Lactation Period, Mare Age, and Foaling on the Chemical and Physical Composition of Milk from Kazakh Mares Kept Under Natural Pasture Conditions

This study aimed to evaluate the chemical composition of milk from Kazakh mares kept under free-grazing conditions on natural pasture without supplementary feeding. Fifty Kazakh mares were aged 3 to 13 years, kept in herds, and categorized by age, number of foalings, and lactation stage for statistical analysis. Milk samples were collected, chilled, and analyzed on the same day using a Milkoscan FT2. The composition of fat, protein, lactose, total solids, casein, and other components was examined. Statistical analyses, including ANOVA, PCA, CDA, and Pearson correlation analysis, were performed using JMP 17 Pro to assess the effects of lactation stage, mare age, and foaling number and to identify key relationships. The results showed that milk composition was significantly influenced by these factors. Milk from the late-lactation stage contained higher protein, lactose, and total nutrients, while milk from the early-lactation stage had a higher sugar content and acidity. Older mares and those with higher foalings produced milk with higher concentrations of glucose and galactose, while younger mares and those with fewer foalings produced milk with higher fat. A key aspect of this experiment was that all mares grazed exclusively on natural pastures without supplementation, allowing for an objective assessment of their inherent productive potential. These findings deepen the understanding of mare milk composition dynamics in Kazakh breed horses under extensive management, supporting its potential for organic dairy production.