Occurrence, pathogens and risk factors for subclinical mastitis in dairy goats

ABSTRACT Milk samples from 257 goats and 513 half udders of 10 dairy goat farms were analyzed by microbiological culture, to evaluate the sanitary management, and epidemiological questionnaire results. Multivariate analysis of risk factors for subclinical mastitis in goats, with the adjusted Odds Ratio for subclinical mastitis was performed. The prevalence of subclinical mastitis in goats by microbiological culture was 43.6%, and clinical mastitis was 5.84%. From 178 positive teats by microbiological culture, the most prevalent pathogens were coagulase-negative staphylococci - CNS (70%), S. aureus (13.5%), S. intermedius (7.9%), and Enterobacteriaceae (4%). The risk factors analysis revealed significant association between the disease and the flock size (OR= 3.33; P= 0.0268), and the farm was a confounding factor, being kept in the final statistical model. Despite the non-identification of all the factors associated with subclinical mastitis in herds and the existence of confounding factors that hinder statistical analyzes, the study of risk factors is important for the improvement of disease control and prevention programs in dairy goat, and it can be used as a tool in the reduction of environmental and contagious pathogens such as staphylococci that were the most identified pathogens causing caprine mastitis in the study.

摘要
本研究采用微生物培养法，对10个奶山羊养殖场的257只山羊及513个半乳房的乳样开展检测，旨在评估养殖场卫生管理水平并分析流行病学调查问卷结果。
针对山羊亚临床乳腺炎的危险因素，本研究开展多变量分析，并计算其校正比值比（adjusted Odds Ratio）。
经微生物培养检测，山羊亚临床乳腺炎检出率为43.6%，临床乳腺炎检出率为5.84%。
在178份微生物培养呈阳性的乳头样本中，优势致病菌依次为凝固酶阴性葡萄球菌（coagulase-negative staphylococci，CNS）（70%）、金黄色葡萄球菌（S. aureus）（13.5%）、中间葡萄球菌（S. intermedius）（7.9%）以及肠杆菌科（Enterobacteriaceae）（4%）。
危险因素分析结果显示，该病与养殖群体规模存在显著相关性（OR=3.33；P=0.0268），且养殖场作为混杂因素被纳入最终统计模型。
尽管本研究尚未明确奶山羊群中亚临床乳腺炎的全部相关危险因素，且存在干扰统计分析的混杂因素，但开展危险因素研究对优化奶山羊乳腺炎防控方案具有重要意义，同时可作为降低环境及接触性致病菌（如本研究中检出率最高的葡萄球菌）感染的有效工具。