Mekonnen S A, Koop G, Melkie S T, Getahun C D, Hogeveen H, Lam T J G M
Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL, Utrecht, The Netherlands; Faculty of Veterinary Medicine, University of Gondar, P.O. Box 196, Gondar, Ethiopia.
Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL, Utrecht, The Netherlands.
Prev Vet Med. 2017 Sep 15;145:23-31. doi: 10.1016/j.prevetmed.2017.06.009. Epub 2017 Jun 21.
Knowledge of mastitis pathogens and their predominance as well as understanding of risk factors are prerequisites to improve udder health in a herd, region or country. In Ethiopia, such information is scarce, despite the fact that mastitis is an important cattle disease in the country. A cross-sectional study that describes prevalence and causative agents of subclinical mastitis (SCM) as well as risk factors at cow and herd level was conducted on 167 dairy farms in North-West Ethiopia. On average, 33% of the quarters and 62% of the cows were California Mastitis Test (CMT) positive, but the within herd quarter level prevalence ranged between 0 and 100%. A total of 1543 milk samples, being 27 quarters that showed signs of CM, 606 CMT positive quarters and 910 CMT negative quarters were cultured, respectively 40%, 67% and 47% was positive on bacteriological culture. Coagulase negative staphylococci (CNS) (31%) followed by Staphylococcus aureus (9%) were the pathogens most frequently isolated. Based on face-to-face questionnaire data, 35 herd level and 13 cow level factors were evaluated for their association with SCM (based on CMT) and with a positive culture for any bacteria, CNS or S. aureus. Cows with a history of CM, of higher parity, >150days in milk (DIM) and herds with owners that have >10th grade level of education had higher odds of SCM. The odds of being culture positive for any bacteria was higher in cows with ≥25% Holstein Friesian blood level (HBL), >150 DIM, housed on cemented floors, and milked by squeezing rather than stripping. Similarly, the odds of culturing CNS was higher in cows with 25-50% HBL, >150 DIM, and milked by squeezing. Staphylococcus aureus was more often found in cows with a history of CM and in larger herds. Checking the udder for mastitis, feeding cows according to their requirements and allowing calves to suckle the cows were negatively associated with SCM, with culturing any bacteria and with culturing CNS, respectively. Higher odds of SCM and of culturing CNS were found in herds owned by members of a dairy cooperative. In summary, we identified a high prevalence of SCM and intramammary infections with substantial variation between farms, and we found a number of risk factors explaining this variation. The risk factors for mastitis that were identified in this study can form the basis of an udder health control program specific for the dairy industry in North-West Ethiopia.
了解乳腺炎病原体及其优势，以及理解风险因素，是改善牛群、地区或国家乳房健康的先决条件。在埃塞俄比亚，尽管乳腺炎是该国一种重要的牛病，但此类信息却很匮乏。在埃塞俄比亚西北部的167个奶牛场进行了一项横断面研究，描述亚临床乳腺炎（SCM）的患病率、病原体以及奶牛和牛群层面的风险因素。平均而言，33%的乳腺区和62%的奶牛加利福尼亚乳腺炎检测（CMT）呈阳性，但牛群内乳腺区层面的患病率在0%至100%之间。共采集了1543份牛奶样本，分别对27个有临床乳腺炎症状的乳腺区、606个CMT阳性乳腺区和910个CMT阴性乳腺区进行培养，细菌培养阳性率分别为40%、67%和47%。凝固酶阴性葡萄球菌（CNS）（31%），其次是金黄色葡萄球菌（9%），是最常分离出的病原体。基于面对面问卷调查数据，评估了35个牛群层面和13个奶牛层面的因素与SCM（基于CMT）以及任何细菌、CNS或金黄色葡萄球菌培养阳性之间的关联。有临床乳腺炎病史、胎次较高、泌乳天数>150天（DIM）的奶牛，以及所有者教育程度>10年级的牛群，患SCM的几率更高。荷斯坦弗里生血统水平（HBL）≥25%、泌乳天数>150天、饲养在水泥地面且采用挤奶而非手工挤奶的奶牛，任何细菌培养阳性的几率更高。同样，HBL为25%-50%、泌乳天数>150天且采用挤奶方式的奶牛，CNS培养阳性的几率更高。金黄色葡萄球菌更常见于有临床乳腺炎病史的奶牛和较大的牛群中。检查乳房是否患乳腺炎、根据奶牛需求喂养以及让小牛吸吮奶牛乳房，分别与SCM、任何细菌培养阳性和CNS培养阳性呈负相关。在由乳制品合作社成员拥有的牛群中，SCM和CNS培养阳性的几率更高。总之，我们发现SCM和乳房内感染的患病率很高，且不同农场之间存在很大差异，并且我们发现了一些解释这种差异的风险因素。本研究中确定的乳腺炎风险因素可构成埃塞俄比亚西北部乳制品行业乳房健康控制计划的基础。
