Changes in Udder Compartments (Alveolar and Cisternal) Depending on Lactation Stage and Parity in Crossbred Cows

This study investigates morphological and compositional variations in the mammary gland of crossbred dairy cows, with specific attention to the udder cisterns and alveoli across different stages of lactation and parities. The primary objectives were: (1) to assess the dimensional changes in the udder cisterns and alveoli in relation to lactation stage and parity, and (2) to analyze variations in milk composition within the cisternal and alveolar compartments. Twenty-eight crossbred dairy cows, comprising both primiparous and multiparous individuals, were evaluated across three distinct lactation phases: early (1–3 months), mid (4–6 months), and late (7 months to drying off). The investigation spanned an 11-month period from January to November 2022. Milk samples from the udder and teat cisterns were analyzed using thermogravimetric methodology. Findings revealed that cisternal milk constituted approximately 31.35–31.95% of total udder milk in both primiparous and multiparous cows. In contrast, the alveolar compartments in multiparous and primiparous cows contributed up to 70% and 72% of total milk fat, respectively (P < 0.05). Notably, no statistically significant differences (P > 0.05) were observed in average fat, protein, lactose, and solids-not-fat (SNF) percentages between the cisternal and alveolar compartments in primiparous cows. Cisternal milk volume increased during early and mid-lactation but declined in late lactation, whereas alveolar milk volume demonstrated an inverse trend. A significant decrease of 18% (P < 0.05) in alveolar milk volume was observed from early to late lactation, with no further reduction noted from mid to late stages. Cisternal milk volume remained stable from early to mid-lactation but declined by 16% (P < 0.05) in the late phase. In conclusion, the crossbred dairy cows exhibited favorable udder morphology, characterized by medium-sized cisterns and teats, suggesting suitability for mechanical milking. Multiparous cows showed superior performance in both cisternal and alveolar milk yield compared to primiparous counterparts. These findings underscore the productive potential of crossbred cows, although enhancements in nutritional management are recommended to optimize milk composition. Further investigations with larger sample sizes are warranted to substantiate these preliminary observations.