Goodhope R G, Meek A H
Can J Comp Med. 1980 Oct;44(4):351-7.
Data from Ontario dairy cattle herds which had had a high average milk gel index for 1978 (cases) and from other herds which had had a low average during the same period (controls) were collected and analyzed using case control techniques. The purpose of the study was to contrast factors of husbandry and management between the two groups and to determine the relative contribution of each of these factors on mastitis (as determined indirectly by the milk gel index) at the herd level. Control herds had higher average production levels than did case herds, shipping 1807 litres more milk per cow per year. Milk from control herds averaged 0.06 percentage points higher in butterfat, 0.19 percentage points higher in lactose and 0.05 percentage points lower in total protein. However, many factors can influence production, therefore these latter differences, in both shipped milk and composition, can not be attributed solely to differences in the prevalence of mastitis between the two groups. Control herds were more likely to use teat dip, receive regular veterinary service, use dry cow antibiotic preparations and have knowledge concerning subclinical mastitis than were case herds. Control herds also tended to raise more of their own replacements, have a higher culling rate for reasons of low production and have a more modernized dairy operation. Case herds, on the other hand, were more likely to scrutinize foremilk, use more milking units per operator and wait longer between the start of stimulation and attachment of the milking unit. The study confirms, under natural field conditions, the importance of integrated mastitis control practices and also reaffirms the relative importance of practices such as the use of teat dips and dry cow antibiotic preparations.
收集了安大略省奶牛群1978年平均乳凝胶指数较高的牛群（病例组）以及同期平均乳凝胶指数较低的其他牛群（对照组）的数据，并采用病例对照技术进行分析。该研究的目的是对比两组之间的饲养和管理因素，并确定这些因素中每一个因素在牛群水平上对乳腺炎（由乳凝胶指数间接测定）的相对影响。对照组牛群的平均产量水平高于病例组牛群，每头牛每年多运送1807升牛奶。对照组牛群的牛奶平均乳脂含量高0.06个百分点，乳糖含量高0.19个百分点，总蛋白含量低0.05个百分点。然而，许多因素会影响产量，因此，所运送牛奶及其成分的这些差异不能仅仅归因于两组之间乳腺炎患病率的差异。与病例组牛群相比，对照组牛群更有可能使用乳头浸液、接受定期兽医服务、使用干奶牛抗生素制剂并了解亚临床乳腺炎。对照组牛群也倾向于更多地饲养自己的后备牛，因产量低而淘汰率更高，并且奶牛场经营更现代化。另一方面，病例组牛群更有可能仔细检查前奶，每个操作人员使用更多的挤奶设备，并且在开始刺激和连接挤奶设备之间等待更长时间。该研究证实了在自然田间条件下综合乳腺炎控制措施的重要性，同时也重申了诸如使用乳头浸液和干奶牛抗生素制剂等措施的相对重要性。
