Business Economics, Wageningen University, Hollandseweg 1, 6706 KN, Wageningen, the Netherlands.
J Dairy Sci. 2011 Jan;94(1):235-49. doi: 10.3168/jds.2010-3528.
Assessment of milk quality is based on bulk milk testing and farm certification on process quality audits. It is unknown to what extent dairy farm audits improve milk quality. A statistical analysis was conducted to quantify possible associations between bulk milk testing and dairy farm audits. The analysis comprised 64.373 audit outcomes on 26,953 dairy farms, which were merged with all conducted laboratory tests of bulk milk samples 12 mo before the audit. Each farm audit record included 271 binary checklist items and 52 attention point variables (given to farmers if serious deviations were observed), both indicating possible deviations from the desired farm situation. Test results included somatic cell count (SCC), total bacterial count (TBC), antimicrobial drug residues (ADR), level of butyric acid spores (BAB), freezing point depression (FPD), level of free fatty acid (FFA), and milk sediment (SED). Results show that numerous audit variables were related to bulk milk test results, although the goodness of fit of the models was generally low. Cow hygiene, clean cubicles, hygiene of milking parlor, and utility room were positively correlated with superior product quality, mainly with respect to SCC, TBC, BAB, FPD, FFA, and SED. Animal health or veterinary drugs management (i.e., drug treatment recording, marking of treated animals, and storage of veterinary drugs) related to SCC, FPD, FFA, and SED. The availability of drinking water was related to TBC, BAB, FFA, and SED, whereas maintenance of the milking equipment was related mainly to SCC, FPD, and FFA. In summary, bulk milk quality and farm audit outcomes are, to some degree, associated: if dairy farms are assessed negatively on specific audit aspects, the bulk milk quality is more likely to be inferior. However, the proportion of the total variance in milk test results explained by audits ranged between 4 and 13% (depending on the specific bulk milk test), showing that auditing dairy farms provides additional information but has a limited association with the outcome of a product quality control program. This study suggests that farm audits could be streamlined to include only relevant checklist items and that bulk milk quality monitoring could be used as a basis of selecting farms for more or less frequent audits.
牛奶质量的评估基于牛奶的批量测试和农场对加工质量审核的认证。目前尚不清楚对奶牛场审核在多大程度上可以提高牛奶质量。本研究通过统计分析来量化批量测试和奶牛场审核之间可能存在的关联。该分析包含了 26953 个奶牛场的 64373 次审核结果，这些结果与审核前 12 个月进行的所有批量牛奶样本的实验室测试结果相合并。每份农场审核记录包含 271 项二进制检查表项目和 52 个关注点变量（如果发现严重偏差，则提供给农民），两者都表明与期望的农场情况存在偏差。测试结果包括体细胞计数（SCC）、总细菌计数（TBC）、抗菌药物残留（ADR）、丁酸孢子水平（BAB）、冰点降低（FPD）、游离脂肪酸水平（FFA）和牛奶沉淀（SED）。结果表明，许多审核变量与批量牛奶测试结果相关，尽管模型的拟合优度通常较低。牛的卫生、清洁牛栏、挤奶厅的卫生和杂物间的卫生与优质产品质量呈正相关，主要与 SCC、TBC、BAB、FPD、FFA 和 SED 有关。动物健康或兽药管理（即药物治疗记录、标记治疗动物和储存兽药）与 SCC、FPD、FFA 和 SED 有关。饮用水的供应与 TBC、BAB、FFA 和 SED 有关，而挤奶设备的维护主要与 SCC、FPD 和 FFA 有关。总的来说，批量牛奶质量和农场审核结果在一定程度上是相关的：如果奶牛场在特定的审核方面被评估为负面，那么牛奶的质量就更有可能下降。然而，审核对牛奶测试结果总方差的解释比例在 4%到 13%之间（取决于具体的批量牛奶测试），这表明对奶牛场进行审核提供了额外的信息，但与产品质量控制计划的结果相关性有限。本研究表明，农场审核可以简化为只包括相关的检查表项目，并且可以将批量牛奶质量监测作为选择进行更频繁或不频繁审核的农场的基础。
