Fthenakis George C
Veterinary Faculty, University of Thessaly, 43100 Karditsa, Greece.
Animals (Basel). 2023 Nov 16;13(22):3541. doi: 10.3390/ani13223541.
The objective of the present study was to propose thresholds of somatic cell counts in bulk-tank milk indicative of the prevalence of subclinical mastitis in a flock. A retrospective analysis was performed on data from a longitudinal survey of subclinical mastitis in Greece, in which the prevalence of subclinical mastitis in 12 flocks sampled four times throughout a milking period was evaluated by collecting milk samples from individual ewes for bacteriological and cytological testing; further, cell counts in the bulk-tanks of the farms were also measured during the visits. Four cohorts were created: A, with cell counts in the bulk-tank milk between 0.100 × 10 and 0.400 × 10 cells mL, B, with cell counts between 0.400 × 10 and 650 × 10 cells mL, C, with cell counts between 0.650 × 10 and 900 × 10 cells mL, and D, with SCC between 0.900 × 10 and 1.450 × 10 cells mL. There was a significant positive correlation between prevalence of the infection in the flocks and somatic cell counts in bulk-tank milk on the same sampling occasion ( < 0.0001). There was also evidence of significant differences between the four cohorts in the mean prevalence rate of the infection ( < 0.0001). Ninety-five percent confidence intervals of the prevalence of subclinical mastitis according to the somatic cell counts in the bulk-tank milk were calculated as follows: for cohort A, 8.7% to 12.1%, for B, 12.4% to 19.4%, for C, 22.5% to 30.8% and for D, 27.3% to 45.3%. The information that may be thus obtained can be useful in guiding the implementation of various health management procedures for mastitis control in sheep flocks, with no need to perform milk sample collection from ewes and subsequent laboratory examinations.
本研究的目的是提出用于表明羊群中亚临床型乳腺炎患病率的奶罐乳体细胞计数阈值。对希腊一项关于亚临床型乳腺炎的纵向调查数据进行了回顾性分析，在该调查中，通过从每只母羊采集奶样进行细菌学和细胞学检测，评估了12个羊群在一个挤奶期内四次采样时亚临床型乳腺炎的患病率；此外，在每次走访期间还测量了各农场奶罐中的细胞计数。创建了四个队列：A组，奶罐乳体细胞计数在0.100×10⁵至0.400×10⁵个/mL之间；B组，细胞计数在0.400×10⁵至0.650×10⁵个/mL之间；C组，细胞计数在0.650×10⁵至0.900×10⁵个/mL之间；D组，体细胞计数在0.900×10⁵至1.450×10⁵个/mL之间。在同一采样时间，羊群中感染患病率与奶罐乳体细胞计数之间存在显著正相关（P＜0.0001）。四个队列之间在感染平均患病率方面也存在显著差异（P＜0.0001）。根据奶罐乳体细胞计数计算的亚临床型乳腺炎患病率的95%置信区间如下：A组为8.7%至12.1%，B组为12.4%至19.4%，C组为22.5%至30.8%，D组为27.3%至45.3%。由此获得的信息可用于指导实施各种用于控制绵羊群乳腺炎的健康管理程序，而无需从母羊采集奶样并进行后续实验室检测。
