Brown M B, Shearer J K, Elvinger F
Department of Infectious Diseases, College of Veterinary Medicine, University of Florida, Gainesville 32610-0633.
J Am Vet Med Assoc. 1990 Apr 1;196(7):1097-101.
In October 1985, mycoplasmas were isolated from bulk tank milk samples in a large Florida dairy (greater than 1,400 lactating cows). At that time, measures to isolate and control the spread of infection were instituted. In an initial screening test, Mycoplasma bovis was isolated from 21 of 153 milking string samples (milk from all quarters of 10 cows/string). Composite quarter milk samples from all quarters of every individual lactating cow in the herd were obtained for culture in November 1985 and December 1985. In October, 88 of 1,535 (5.7%) cows were identified as Mycoplasma-positive. An additional 31 Mycoplasma-infected cows were identified in December. The dairy elected to maintain the infected cows in a separate Mycoplasma-positive subherd, which would be milked at the end of each milking session. Seven additional Mycoplasma-positive cows were identified at initiation of lactation. All newly identified infected cows were transferred to the Mycoplasma-positive subherd. After segregation of Mycoplasma-positive cows, bulk tank milk samples obtained routinely from the main herd remained culture negative throughout the study. From February 1986 to October 1986, quarter milk samples were obtained monthly from cows in the Mycoplasma-positive subherd. Any cow that developed clinical mastitis or substantial decrease in milk production was, at the discretion of the herdsman, culled. Of the 126 cows in the subherd, 22 (17.5%) were culled for mastitis, 35 (27.8%) were culled for low production, and 9 (7.1%) were culled for other reasons. Of the remaining 60 cows, 16 (12.7% of the 126 cows) were Mycoplasma-positive on the basis of results from one or more samples obtained after February 1986.(ABSTRACT TRUNCATED AT 250 WORDS)
1985年10月，在佛罗里达州一家大型奶牛场（有超过1400头泌乳奶牛）的贮奶罐牛奶样本中分离出支原体。当时，采取了隔离和控制感染传播的措施。在初步筛查试验中，从153个挤奶组样本（每组10头奶牛每个乳腺的牛奶）中的21个样本中分离出牛支原体。1985年11月和12月，采集了牛群中每头泌乳奶牛各个乳腺的混合乳腺牛奶样本进行培养。10月，1535头奶牛中有88头（5.7%）被鉴定为支原体阳性。12月又鉴定出31头感染支原体的奶牛。该奶牛场选择将感染奶牛留在一个单独的支原体阳性亚群中，在每次挤奶结束时对其进行挤奶。在泌乳开始时又鉴定出7头支原体阳性奶牛。所有新鉴定出的感染奶牛都被转移到支原体阳性亚群中。在将支原体阳性奶牛隔离后，在整个研究过程中，从主要牛群中常规采集的贮奶罐牛奶样本培养结果均为阴性。1986年2月至1986年10月，每月从支原体阳性亚群中的奶牛采集乳腺牛奶样本。任何出现临床乳腺炎或产奶量大幅下降的奶牛，由牧民自行决定进行淘汰。在该亚群的126头奶牛中，22头（17.5%）因乳腺炎被淘汰，35头（27.8%）因产量低被淘汰，9头（7.1%）因其他原因被淘汰。在其余60头奶牛中，根据1986年2月以后获得的一个或多个样本结果，有16头（占126头奶牛的12.7%）为支原体阳性。（摘要截短至250字）
