Zone of inhibition (Mean ± Standard error).

This study aimed to isolate and characterize Staphylococcus aureus (S. aureus) from samples of mastitis milk taken from dairy cattle in Punjab’s Narowal District. 200 milk samples were collected aseptically from different dairy herds in the district, including clinical mastitis (CM) and sub-clinical mastitis (SCM) cows. Blood agar and mannitol salt agar were used for S. aureus isolation and identification. Selective media were then used for additional purification. Observations of morphological and biochemical traits verified the existence of S. aureus. Through questionnaire-based surveys, the prevalence of S. aureus mastitis was identified, and risk variables linked to its incidence were evaluated. The findings showed that S. aureus mastitis was prevalent in 42.5% of cases, with sub-clinical cases having a greater incidence (45.8%) than clinical cases (37.5%). Risk factors such as distance from dung pile to stall(m), source of water, dung removal per day, lactation period (weeks), parity, effect of milk yield (L), traumatic injury of udder, housing type, floor type, teat dipping, and bedding type was identified and their relationship to the occurrence of S. aureus mastitis was studied. Tests for antibiotic sensitivity revealed that S. aureus isolates were responsive to gentamycin, ceftiofur, tetracycline, enrofloxacin, and ciprofloxacin but extremely resistant to penicillin and amoxicillin. Additionally, the Somatic Cell Count (SCC) and California Mastitis Test (CMT) were used at different intervals to assess the effectiveness of the medication. Furthermore, compared to other treatment groups, a larger percentage of cure rates was seen in the groups receiving ceftiofur and enrofloxacin. Overall, this study contributes to the development of more effective management methods for S. aureus mastitis in dairy calves by offering insightful information about the condition’s prevalence, risk factors, antibiotic sensitivity, and effectiveness of treatment.

本研究旨在从旁遮普省纳罗瓦尔地区奶牛的乳腺炎乳汁样本中分离并鉴定金黄色葡萄球菌（Staphylococcus aureus, S. aureus）。研究人员从该地区不同奶牛场无菌采集200份乳样，涉及临床型乳腺炎（clinical mastitis, CM）与亚临床型乳腺炎（sub-clinical mastitis, SCM）患病奶牛。采用血琼脂平板与甘露醇盐琼脂完成S. aureus的分离与鉴定，随后借助选择性培养基开展进一步纯化。通过形态学与生化性状观察，确认了S. aureus的存在。本研究通过问卷调查明确了S. aureus乳腺炎的流行率，并评估了与其发病相关的风险因素。结果显示，S. aureus乳腺炎整体检出率为42.5%，其中亚临床病例的发病率（45.8%）高于临床病例（37.5%）。研究共鉴定出多项与发病相关的风险因素，包括粪堆至牛舍的距离（米）、水源类型、每日清粪频次、泌乳周期（周）、胎次、产奶量（升）、乳房外伤、畜舍类型、地面类型、乳头药浴以及垫料类型，并分析了上述因素与S. aureus乳腺炎发生的关联。抗生素敏感性试验结果表明，S. aureus分离株对庆大霉素、头孢噻呋、四环素、恩诺沙星及环丙沙星敏感，但对青霉素与阿莫西林呈现高度耐药性。此外，本研究在不同时间节点采用体细胞计数（Somatic Cell Count, SCC）与加州乳腺炎试验（California Mastitis Test, CMT）评估药物治疗效果。进一步分析发现，与其他治疗组相比，接受头孢噻呋与恩诺沙星治疗的组别治愈率更高。总体而言，本研究通过揭示S. aureus乳腺炎的流行特征、风险因素、抗生素敏感性及治疗效果，为奶牛犊牛S. aureus乳腺炎的高效防控管理方案研发提供了关键参考依据。