Departamento de Producción Animal, Facultad de Veterinaria, Universidad de León, 24071-León, Spain.
J Dairy Sci. 2010 Apr;93(4):1587-95. doi: 10.3168/jds.2009-2838.
To study the variations of bulk tank milk variables in dairy ewe flocks and to identify the main target practices and flock groups to improve milk quality and safety, a total of 71,228 records of antibiotic residue (AR) and milk yield and 68,781 records of somatic cell count (SCC) and total bacterial count (TBC) were obtained over 5 yr from the same 209 dairy ewe flocks of the Assaf breed belonging to the Consortium for Ovine Promotion of Castilla-León (Spain). Based on a logistic regression model, year, month, semester, SCC, TBC, dry therapy, and milk yield significantly contributed to AR variation. High SCC was associated with increased AR violations. When antibiotic dry therapy was implemented, AR occurrence was higher than when this practice was not used. A polynomial monthly distribution throughout the year was observed for AR occurrence; the highest values were in autumn, coinciding with low milk yields per flock. Yearly occurrences drastically diminished from 2004 (1.36%) to 2008 (0.30%), probably as a result of effective educational programs. The mixed-model ANOVA of factors influencing variation in SCC and TBC indicated that year, month, AR, dry therapy group, milking type, and year interactions were significant variation factors for SCC and TBC; mathematical model accounted for 74.1 and 35.4% of total variance for each variable, respectively. Differences in management and hygiene practice caused significant SCC and TBC variations among flocks and within flocks throughout the 5-yr study. Over time, continuously dry treated flocks showed lower logSCC (5.80) and logTBC (4.92) than untreated (6.10 and 5.18, respectively) or discontinuously dry treated (6.01 and 5.05, respectively) flocks. Continuously dry treated flocks had lower AR occurrences than did discontinuously dry treated flocks. As a whole, AR occurrence and SCC and TBC bulk tank milk variables can be used for monitoring mammary health and milk hygiene and safety in dairy sheep throughout time.
为了研究奶绵羊群体中大容量牛奶变量的变化，并确定主要的目标实践和羊群群体，以提高牛奶质量和安全性，在 5 年内，从属于西班牙卡斯蒂利亚-莱昂奥弗尼推广联盟的同一 209 个阿萨夫品种奶绵羊群体中，共获得了 71228 份抗生素残留 (AR) 和牛奶产量记录，以及 68781 份体细胞计数 (SCC) 和总细菌计数 (TBC) 记录。基于逻辑回归模型，年份、月份、学期、SCC、TBC、干治疗和牛奶产量对 AR 变化有显著贡献。高 SCC 与 AR 违规增加有关。当实施抗生素干治疗时，AR 的发生高于不使用该治疗时。AR 发生的月分布呈全年多项式分布；最高值出现在秋季，与每群的低牛奶产量相吻合。从 2004 年 (1.36%) 到 2008 年 (0.30%)，年度发生次数急剧减少，这可能是由于有效的教育计划。影响 SCC 和 TBC 变化的因素的混合模型方差分析表明，年份、月份、AR、干治疗组、挤奶类型和年份相互作用是 SCC 和 TBC 的重要变化因素；数学模型分别解释了每个变量总方差的 74.1%和 35.4%。管理和卫生实践方面的差异导致 5 年研究期间羊群之间和羊群内部的 SCC 和 TBC 发生显著变化。随着时间的推移，连续干治疗的羊群的 logSCC(5.80)和 logTBC(4.92)低于未处理的羊群(分别为 6.10 和 5.18)或不连续干治疗的羊群(分别为 6.01 和 5.05)。连续干治疗的羊群的 AR 发生率低于不连续干治疗的羊群。总的来说，AR 发生情况以及 SCC 和 TBC 大容量牛奶变量可用于监测奶绵羊的乳腺健康和牛奶卫生和安全。
