Quality and nutraceutical potential of bovine milk in different production systems and seasons

Abstract: The objective of this work was to evaluate the effect of the interaction between production systems and seasons on the chemical and microbiological qualities of bovine milk, besides proposing a potential nutraceutical index of milk fatty acid profiles. Three farms were assessed monthly, along the different seasons, for four specialization levels of the production systems: highly specialized, specialized, partially specialized, and nonspecialized. The production systems and the seasons jointly interfere in fatty acid profiles, and singly interfere in the chemical and microbiological quality of milk. The highest somatic cell counts and the lowest protein contents were observed in the summer, and the specialization level of the production units had an inverse relationship with the total bacterial count. During winter, nonspecialized systems produced milk with the best nutraceutical index, with the highest contents of polyunsaturated fatty acids, rumenic acid (CLA, 18:2n7-c9,t11) and t10,c12-octadecadienoic acid (CLA, 18:2n6-t10,c12).

摘要：本研究旨在评估生产系统与季节的交互作用对牛乳化学与微生物品质的影响，并提出牛乳脂肪酸谱的潜在营养保健指数。本研究按月于不同季节对3个牧场开展采样，涵盖4种生产系统专业化水平：高度专业化、专业化、部分专业化及非专业化。研究结果表明，生产系统与季节的联合效应会对牛乳脂肪酸谱产生影响，而二者单独作用则会影响牛乳的化学与微生物品质。夏季牛乳的体细胞计数最高、蛋白质含量最低；生产单元的专业化水平与总细菌计数呈负相关关系。冬季非专业化生产系统所产牛乳的营养保健指数最优，其多不饱和脂肪酸、共轭亚油酸（CLA，18:2n7-c9,t11）及t10,c12-十八碳二烯酸（CLA，18:2n6-t10,c12）含量均为最高。