Epidemiology of mastitis and interactions of environmental factors on udder health in the compost barn system

ABSTRACT This study aimed to describe the epidemiological indexes of mastitis, milk quality and udder hygiene in the Compost Barn system, as well as to search for associations between isolated pathogens from milk with compost characteristics. Three dairy herds participated in the study, and the samples were collected during different periods on each farm. Individual milk samples were collected in duplicate for SCC analysis and microbiological culture. Environmental pathogens caused most cases of clinical mastitis on farm 2, and contagious pathogens caused the most cases on farm 1. Bed moisture was not associated with the incidence of environmental pathogens. Most of the animals remained in good udder hygiene during the study. Poor udder hygiene contributed to the increased incidence of environmental pathogens in one of the farms. A higher number of animals with a hygiene score of ≥ 2 were observed during the warmer and rainfall periods. There was no association between hygiene scores and somatic cell counts. The results suggest that pathogens isolated from milk in animals confined in Compost Barn under tropical climate are like other confinement systems adopted elsewhere. The year period influenced the udder hygiene score, reinforcing the importance of bed management throughout the year.摘要 本研究旨在阐明堆肥垫料牛舍（Compost Barn）系统下乳腺炎、牛乳品质与乳房卫生的流行病学指标，并探究牛乳中分离得到的病原菌与堆肥特性之间的关联。本研究纳入3个奶牛场，各农场于不同时段采集样本。每份牛乳采集双份样本，用于体细胞计数（Somatic Cell Count, SCC）分析及微生物培养。农场2的临床乳腺炎病例多由环境型病原菌引发，农场1的临床乳腺炎主要致病菌为接触型病原菌。垫料含水量与环境型病原菌的发病率无显著关联。研究期间，多数受试奶牛的乳房卫生状况良好。在其中一个农场中，乳房卫生不佳会提升环境型病原菌的感染发病率。在暖季与降雨时段，乳房卫生评分≥2分的受试奶牛数量更多。乳房卫生评分与体细胞计数无显著关联。本研究结果显示，热带气候下堆肥垫料牛舍圈养奶牛的牛乳分离病原菌特征，与其他地区采用的圈养系统相仿。年度时段会对乳房卫生评分产生影响，这进一步凸显了全年开展垫料管理的重要性。