Smith K L, Todhunter D A, Schoenberger P S
J Dairy Sci. 1985 Jun;68(6):1531-53. doi: 10.3168/jds.S0022-0302(85)80993-0.
Rate of intramammary infection by coliform bacteria and species of streptococci other than Streptococcus agalactiae (environmental pathogens) was studied in a dairy herd in total confinement. Rate was higher during the dry period than during lactation and increased progressively as parity increased. Rate was maximal during summer and coincided with maximum exposure to coliforms in bedding. Streptococcal infections were longer than coliform. Approximately 59% of streptococcal infections and 69% of coliform infections were present for 30 lactation days or less. Percent quarters infected by day of year varied between .7 and 3.0% for coliform bacteria and between 1.6 and 4.7% for streptococci. Approximately 81% of coliform infections and 53% of streptococcal infections during lactation were clinical. Clinical cases were highest during the first 76 days of lactation and during summer. Only 6.7% of coliform infections resulted in acute coliform mastitis, and all acute cases were during summer or early lactation. Dry cow therapy reduced rate of streptococcal infection during the early dry period but was without effect during the prepartum period. There was no effect of dry cow therapy on coliform infection rate during the dry period. Problems associated with prevalence and control of environmental mastitis were discussed.
在一个完全封闭的奶牛场中，研究了大肠菌群和无乳链球菌以外的链球菌属（环境病原体）引起的乳房内感染率。干奶期的感染率高于泌乳期，且随着胎次增加而逐渐上升。夏季感染率最高，且与垫料中大肠菌群的最大暴露量一致。链球菌感染持续时间比大肠菌群感染长。大约59%的链球菌感染和69%的大肠菌群感染持续30个泌乳日或更短时间。一年中不同日期感染的乳腺象限百分比，大肠菌群在0.7%至3.0%之间，链球菌在1.6%至4.7%之间。泌乳期大约81%的大肠菌群感染和53%的链球菌感染为临床感染。临床病例在泌乳的前76天和夏季最多。只有6.7%的大肠菌群感染导致急性大肠型乳腺炎，且所有急性病例都发生在夏季或泌乳早期。干奶牛治疗降低了干奶早期链球菌感染率，但在产前阶段无效。干奶牛治疗对干奶期大肠菌群感染率没有影响。讨论了与环境性乳腺炎的流行和控制相关的问题。
