Godden S, Bey R, Lorch K, Farnsworth R, Rapnicki P
Department of Veterinary Population Medicine, University of Minnesota, St. Paul 55108, USA.
J Dairy Sci. 2008 Jan;91(1):151-9. doi: 10.3168/jds.2007-0415.
The major objective of this study was to contrast the ability of 4 commonly utilized bedding materials to promote growth of environmental bacteria under controlled conditions. A second objective was to describe the relationship between bacterial growth and specific biochemical or nutritional properties of these bedding materials. Unused samples of clean sand (CS; n = 20), recycled sand (RS; n = 21), digested manure solids (DS; n = 15), and shavings (SH; n = 15) were collected from bedding storage areas on 49 commercial Minnesota and Wisconsin dairy farms. Sterilized bedding samples were inoculated with Klebsiella pneumoniae and Enterococcus faecium then incubated, in triplicate, for 72 h at 37 degrees C. Subsamples were collected after 0, 24, 48, and 72 h of incubation for culture and enumeration of bacteria. Subsamples of bedding were also tested for pH, total C content (%), and total N content (%). If bacterial growth occurred, peak levels were typically achieved within 24 h. Digested manure solids promoted the greatest amounts of growth of K. pneumoniae, followed by RS and then SH, whereas CS promoted the least. There would seem to be a tradeoff in selecting SH as a bedding material, because it supported moderate growth of K. pneumoniae but caused a rapid decline in the numbers of E. faecium. However, RS, CS, and DS each only supported relatively small amounts of growth of E. faecium, so the benefit of SH relative to other bedding materials is limited. High bedding pH may partially explain why some bedding materials supported growth of E. faecium (e.g., DS and RS). Both high bedding pH (e.g., as for DS or RS) and high total C (%) content (e.g., as for DS and SH) may partially explain why some bedding materials supported growth of K. pneumoniae.
本研究的主要目的是对比4种常用垫料在可控条件下促进环境细菌生长的能力。第二个目的是描述细菌生长与这些垫料特定生化或营养特性之间的关系。从明尼苏达州和威斯康星州的49个商业奶牛场的垫料储存区收集了未使用的清洁沙子（CS；n = 20）、再生沙（RS；n = 21）、消化粪便固体（DS；n = 15）和刨花（SH；n = 15）样本。将灭菌后的垫料样本接种肺炎克雷伯菌和粪肠球菌，然后一式三份在37℃下培养72小时。在培养0、24、48和72小时后收集子样本，用于细菌培养和计数。还对垫料子样本的pH值、总碳含量（%）和总氮含量（%）进行了检测。如果发生细菌生长，峰值水平通常在24小时内达到。消化粪便固体促进肺炎克雷伯菌生长的量最大，其次是RS，然后是SH，而CS促进生长的量最少。选择SH作为垫料似乎存在权衡，因为它支持肺炎克雷伯菌适度生长，但导致粪肠球菌数量迅速下降。然而，RS、CS和DS各自仅支持相对少量的粪肠球菌生长，因此SH相对于其他垫料的优势有限。垫料高pH值可能部分解释了为什么一些垫料支持粪肠球菌生长（例如DS和RS）。垫料高pH值（例如DS或RS的情况）和高总碳（%）含量（例如DS和SH的情况）都可能部分解释了为什么一些垫料支持肺炎克雷伯菌生长。
