Department of Population Medicine and Diagnostic Sciences, Cornell College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
J Dairy Sci. 2013 Jun;96(6):3689-702. doi: 10.3168/jds.2012-6271. Epub 2013 Mar 30.
In the past decade, the demand for organic agricultural products has increased rapidly in the United States and worldwide. Milk quality research is of major interest to both consumers and dairy farmers alike. However, scientific data on milk quality, herd management methods, and animal welfare on organic farms in the United States has been lacking before the research from this study. The objective of this study was to evaluate the association of bulk tank milk somatic cell count (SCC) with management characteristics on organic and conventional dairy farms in New York, Oregon, and Wisconsin. Data from similarly sized organic farms (n=192), conventional nongrazing farms (n=64), and conventional grazing farms (n=36) were collected at a single farm visit. Of the 292 farms visited, 290 bulk tank milk samples were collected. Overall, no difference in SCC was observed between the conventional and organic grazing systems. Two models were created to assess the effects of various management and herd characteristics on the logarithmic transformation of the SCC (LSCC), one using data from all herds and one using data from organic herds only. From the total herd model, more grain fed per cow per day was negatively associated with LSCC, whereas a positive bulk tank culture for Staphylococcus aureus and years that a farmer reported being in the dairy business were both positively associated with LSCC. In the organic herd model, a seasonal effect indicated that LSCC tended to increase in the summer and decrease in the winter. Grain fed per cow per day, the use of anionic salts in transition-cow diets, the use of gloves during milking, and regular use of a quarantine unit at milking were all negatively associated with LSCC. Similar to the total herd model, a Staph. aureus-positive bulk tank culture was positively associated with LSCC in the organic model. Standard plate count was also positively associated with LSCC in the organic model. Several variables that were associated with management using external resources were combined to create an external input score. In the total herd model, use of more external resources was negatively associated with LSCC. Conventional herds in the study tended to use more outside management resources than organic herds.
在过去的十年中，美国和全球对有机农产品的需求迅速增长。牛奶质量研究是消费者和奶农都非常关注的问题。然而，在此项研究之前，美国有机农场的牛奶质量、牛群管理方法和动物福利方面的科学数据一直缺乏。本研究的目的是评估美国纽约、俄勒冈和威斯康星州的大罐牛奶体细胞计数（SCC）与管理特性之间的关联。在一次农场访问中收集了类似规模的有机农场（n=192）、传统非放牧农场（n=64）和传统放牧农场（n=36）的数据。在所访问的 292 个农场中，共采集了 290 个大罐牛奶样本。总体而言，传统放牧系统和有机放牧系统之间的 SCC 没有差异。创建了两个模型来评估各种管理和牛群特征对数转换的 SCC（LSCC）的影响，一个使用所有牛群的数据，另一个仅使用有机牛群的数据。从总牛群模型中，每头牛每天饲喂的谷物量与 LSCC 呈负相关，而大罐奶中金黄色葡萄球菌的阳性培养和奶农从事奶牛业的年限与 LSCC 呈正相关。在有机牛群模型中，季节性效应表明 LSCC 在夏季呈上升趋势，冬季呈下降趋势。每头牛每天饲喂的谷物量、在过渡牛日粮中使用阴离子盐、挤奶时戴手套以及定期在挤奶时使用隔离单元都与 LSCC 呈负相关。与总牛群模型类似，有机模型中大罐奶金黄色葡萄球菌阳性培养与 LSCC 呈正相关。在有机模型中，标准平板计数也与 LSCC 呈正相关。与外部资源管理相关的几个变量被组合起来创建一个外部投入得分。在总牛群模型中，使用更多的外部资源与 LSCC 呈负相关。研究中的传统牛群比有机牛群更倾向于使用更多的外部管理资源。
