Borneman Darand L, Ingham Steve
Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison 53706-1565.
Wisconsin Department of Agriculture, Trade, and Consumer Protection, Division of Food Safety, PO Box 8911, Madison 53708-8911.
J Dairy Sci. 2014 May;97(5):2646-52. doi: 10.3168/jds.2013-7784. Epub 2014 Mar 13.
The objective of this study was to determine if a correlation exists between standard plate count (SPC) and somatic cell count (SCC) monthly reported results for Wisconsin dairy producers. Such a correlation may indicate that Wisconsin producers effectively controlling sanitation and milk temperature (reflected in low SPC) also have implemented good herd health management practices (reflected in low SCC). The SPC and SCC results for all grade A and B dairy producers who submitted results to the Wisconsin Department of Agriculture, Trade, and Consumer Protection, in each month of 2012 were analyzed. Grade A producer SPC results were less dispersed than grade B producer SPC results. Regression analysis showed a highly significant correlation between SPC and SCC, but the R(2) value was very small (0.02-0.03), suggesting that many other factors, besides SCC, influence SPC. Average SCC (across 12 mo) for grade A and B producers decreased with an increase in the number of monthly SPC results (out of 12) that were ≤ 25,000 cfu/mL. A chi-squared test of independence showed that the proportion of monthly SCC results >250,000 cells/mL varied significantly depending on whether the corresponding SPC result was ≤ 25,000 or >25,000 cfu/mL. This significant difference occurred in all months of 2012 for grade A and B producers. The results suggest that a generally consistent level of skill exists across dairy production practices affecting SPC and SCC.
本研究的目的是确定威斯康星州奶农每月报告的标准平板计数（SPC）与体细胞计数（SCC）结果之间是否存在相关性。这种相关性可能表明，有效控制卫生条件和牛奶温度（反映在低SPC上）的威斯康星州奶农也实施了良好的畜群健康管理措施（反映在低SCC上）。分析了2012年每个月向威斯康星州农业、贸易和消费者保护部提交结果的所有A级和B级奶农的SPC和SCC结果。A级奶农的SPC结果比B级奶农的SPC结果离散程度小。回归分析表明SPC和SCC之间存在高度显著的相关性，但R²值非常小（0.02 - 0.03），这表明除了SCC之外，许多其他因素也会影响SPC。A级和B级奶农的平均SCC（12个月期间）随着每月SPC结果（12个中的）≤25,000 cfu/mL数量的增加而下降。独立性卡方检验表明，每月SCC结果>250,000个细胞/mL的比例根据相应的SPC结果是≤25,000还是>25,000 cfu/mL而有显著差异。2012年所有月份，A级和B级奶农均出现了这种显著差异。结果表明，在影响SPC和SCC的奶牛生产实践中，普遍存在一致的技术水平。
