PDF(Pubmed)
Abstract：
Recurrent mastitis poses a common challenge on dairy farms. While the impact of repeated mastitis within the same lactation has been investigated, the difference from one lactation to the next, particularly concerning the change of milk and blood metabolites, remains unclear. This study aimed to examine the difference in milk yield, milk composition, and metabolic status in the subsequent lactation between healthy and repeated mastitis in the previous lactation. The study population comprised 50 cows chosen from 400 cows, with 25 having no history of mastitis and 25 experiencing mastitis more than three times during the last lactation. Following dry-off and calving, all cows initiated a new lactation, during which no mastitis was diagnosed until the sample collection period. In the group exposed to repeated mastitis, a significant decrease in milk fat levels was observed in the subsequent lactation, while no change was observed in milk somatic cell count (SCC). Milk collected from cows that had experienced repeated mastitis in the previous lactation exhibited significant increases in the levels of free amino acids, namely valine, proline, and alanine. However, no difference in plasma levels of these amino acids was noted. These results indicate that individuals exposed to repeated mastitis have persistent milk quality changes even after dry-off. Biomarker analysis suggested that the milk valine and proline showed a moderate biomarker potential on Kappa coefficients to characterize cows that have experienced repeated mastitis. Furthermore, the results of biomarker combinations for valine and proline provided the highest specificity (100 %), positive likelihood ratio (infinity), and substantial biomarker potential on kappa coefficients (0.68). These findings significantly enhance our understanding of the pathobiology and etiology of recurrent mastitis and provide a biomarker to characterize cows that have experienced repeated mastitis in the past.
摘要：
复发性乳腺炎对奶牛场构成了共同的挑战。虽然在同一哺乳期内反复乳腺炎的影响已被调查，从一次哺乳到下一次哺乳的区别，特别是关于牛奶和血液代谢物的变化，尚不清楚。这项研究旨在检查产奶量的差异，牛奶成分，和代谢状态在随后的泌乳中介于健康和先前泌乳中的重复乳腺炎之间。研究人群包括从400头牛中选择的50头牛，25人没有乳腺炎病史，25人在最后一次哺乳期间经历了三次以上的乳腺炎。干燥和产卵后，所有奶牛都开始了新的泌乳，在此期间，直到样本收集期才诊断出乳腺炎。在暴露于反复乳腺炎的组中，在随后的泌乳中观察到乳脂水平显着下降，而乳体细胞计数（SCC）未观察到变化。从先前哺乳期反复经历过乳腺炎的奶牛收集的牛奶显示游离氨基酸水平显着增加，即缬氨酸，脯氨酸,还有丙氨酸.然而,这些氨基酸的血浆水平没有差异。这些结果表明，暴露于反复乳腺炎的个体即使在干燥后也具有持续的牛奶质量变化。生物标志物分析表明，牛奶缬氨酸和脯氨酸在Kappa系数上显示出中等的生物标志物潜力，以表征经历反复乳腺炎的奶牛。此外，缬氨酸和脯氨酸的生物标志物组合的结果提供了最高的特异性（100％），正似然比(无穷大)，和相当大的生物标志物潜力对kappa系数（0.68）。这些发现显着增强了我们对复发性乳腺炎的病理生物学和病因学的理解，并提供了生物标志物来表征过去经历过反复乳腺炎的奶牛。
