Hassan Z, Daniel R C, O'Boyle D, Frost A J
Veterinary Services, Negri Sembilan Dural, Malaysia.
Vet Rec. 1999 Nov 27;145(22):635-9. doi: 10.1136/vr.145.22.635.
Quarter milk samples were taken from 150 cows from three dairy farms in south-east Queensland at drying off, two, four and six weeks after drying off, at calving, and one, two and three weeks after calving. In each of the herds, the cows were randomly allocated to three groups of approximately equal size. One group had all the quarters of all the cows treated at drying off with a dry cow antibiotic infusion containing cloxacillin; the second group was given no treatment, and the third group had selected quarters treated on the basis of their high activity of N-acetyl-beta-D-glucosaminidase at drying off. Dry cow treatment resulted in a marked reduction in the number of infected quarters at two and four weeks after drying off, so that the comprehensively treated group had significantly less infected quarters at these times (P<0.02). Twelve dinical cases of mastitis were detected two weeks after drying off in the untreated groups, 10 in the untreated quarters of the selectively treated groups, and no cases in the comprehensively treated groups. These cases were due mainly to Streptococcus uberis and Streptococcus dysgalactiae. The number of infected untreated quarters increased markedly between drying off and two weeks later, but in all three groups there was a marked decrease in the number of infected quarters between six weeks after drying off and calving, suggesting that the mammary glands were more able to overcome infections at this time.
在昆士兰州东南部的三个奶牛场，于150头奶牛干奶期、干奶后两周、四周和六周、产犊时以及产犊后一周、两周和三周采集四分之一的牛奶样本。在每个牛群中，奶牛被随机分为三组，每组大小大致相等。一组在干奶期对所有奶牛的所有乳腺进行治疗，使用含氯唑西林的干奶牛抗生素灌注；第二组不进行治疗，第三组根据干奶期N - 乙酰 - β - D - 氨基葡萄糖苷酶活性高的情况选择乳腺进行治疗。干奶牛治疗导致干奶后两周和四周时感染乳腺的数量显著减少，因此在这些时候，全面治疗组的感染乳腺明显更少（P<0.02）。在干奶后两周，未治疗组检测到12例临床乳腺炎病例，选择性治疗组的未治疗乳腺中有10例，而全面治疗组未出现病例。这些病例主要由乳房链球菌和停乳链球菌引起。在干奶期和两周后，未治疗的感染乳腺数量显著增加，但在所有三组中，从干奶后六周至产犊期间，感染乳腺的数量显著减少，这表明此时乳腺更能克服感染。
