Frequency of microorganisms isolated at different stages of lactation and milk production loss associated with somatic cell count and to mastitis-causing pathogens

ABSTRACT The aim of this study was to evaluate the frequency of isolation of agents causing subclinical mastitis in a herd and to estimate production losses associated with SCC> 200,000cells/mL. Three 7-day interval microbiological cultures were performed in all lactating animals from the same farm that was evaluated from June to July. To evaluate the negative and positive isolation frequencies between the lactation phases, a Chi-square test was performed. Simple linear regressions were performed to evaluate the lactation curve of animals grouped by pathogens isolated from negative cows in the microbiological culture and with SCC摘要 本研究旨在评估某牛群中亚临床乳腺炎致病菌的分离率，并估算体细胞数（Somatic Cell Count, SCC）＞200000个/毫升相关的生产损失。本研究于6月至7月间，对同一场区的所有泌乳动物开展了三次间隔7天的微生物培养检测。为比较不同泌乳阶段的病原体分离阳性率与阴性率差异，采用卡方（Chi-square）检验进行分析。通过简单线性回归分析，对经微生物培养呈阴性且体细胞数符合条件的泌乳动物按分离得到的病原体分组，以此评估各组的泌乳曲线。