Goldberg J J, Wildman E E, Pankey J W, Kunkel J R, Howard D B, Murphy B M
Department of Animal Sciences, University of Vermont, Burlington 05401.
J Dairy Sci. 1992 Jan;75(1):96-104. doi: 10.3168/jds.S0022-0302(92)77743-1.
Monthly bulk tank milk samples and veterinary records were analyzed for 1 yr on 15 Vermont dairy farms. Data were evaluated using ANOVA to compare effects of grazing management systems on milk quality and udder health. Systems evaluated were intensively managed rotational grazing, traditional continuous grazing, and confinement housing. Bulk tank samples were evaluated for standard plate count, bacterial type counts on tryptose-blood-esculin agar, and SCC. Veterinary records were evaluated for incidence of clinical mastitis, udder edema, and teat injuries. Within- and between-treatment group analyses were conducted by season, herd size, and udder sanitation systems. Mean standard plate counts were lower in rotationally grazed herds than counts of confined herds during the grazing season. Similarly, rotationally grazed herds with fewer than 60 cows had lower standard plate counts than confined herds of similar size. Mean bulk tank counts of streptococci other than Streptococcus agalactiae during the grazing season differed among treatments. The lowest counts occurred in rotationally grazed herds. Among herd using predip products recognized as efficacious, fewer streptococci other than S. agalactiae were isolated from bulk tank milk of rotationally grazed herds than confined herds. Rotationally grazed herds using postdips recognized as efficacious had lower SCC than those using unrecognized postdips. No udder health differences were observed among grazing treatments.
对佛蒙特州15个奶牛场的月度储奶罐牛奶样本和兽医记录进行了为期1年的分析。使用方差分析对数据进行评估，以比较放牧管理系统对牛奶质量和乳房健康的影响。评估的系统包括集约化管理的轮牧、传统的连续放牧和圈养。对储奶罐样本进行标准平板计数、胰蛋白胨-血液-七叶苷琼脂上的细菌类型计数以及体细胞计数（SCC）评估。对兽医记录进行临床乳腺炎、乳房水肿和乳头损伤发生率的评估。在季节、牛群规模和乳房卫生系统方面进行组内和组间分析。在放牧季节，轮牧牛群的平均标准平板计数低于圈养牛群。同样，奶牛数量少于60头的轮牧牛群的标准平板计数低于类似规模的圈养牛群。在放牧季节，不同处理之间无乳链球菌以外的链球菌的储奶罐平均计数存在差异。最低计数出现在轮牧牛群中。在使用被认为有效的乳头浸液产品的牛群中，从轮牧牛群的储奶罐牛奶中分离出的无乳链球菌以外的链球菌比圈养牛群少。使用被认为有效的乳头后浸液的轮牧牛群的体细胞计数低于使用未被认可的乳头后浸液的牛群。在放牧处理之间未观察到乳房健康差异。
