Factors associated with intra-mammary infections dynamic and development of tailored sampling strategies and analytical methods.

乳房炎是一种乳腺炎症，通常由细菌感染引起，是一种多方面的疾病，是最昂贵的奶牛健康问题之一。据估计，加拿大乳制品生产商每年的乳房炎费用约为3亿美元。乳房炎降低了奶牛的产奶量，影响了动物的福利，疾病和不适的迹象清晰可见和可测量。此外，用于治疗和预防乳房炎的抗生素治疗在加拿大奶牛场使用的抗生素中占很大比例，并构成牛奶供应中可能威胁公众健康的残留风险。最后，目前还没有诊断乳房内感染(IMI)的金标准测试，这一后续方面在研究和实践中都有重要影响。**当前研究计划的长期目标是进一步提高我们对乳房炎病原体流行病学的了解，并开发新的工具来监测乳牛场IMI的动态。我们首先建议定量评估不同采样方案对乳房健康研究中常见结果的有效性的影响。这第一个目标将允许为纵向乳房健康研究定义明确的抽样战略指南，这是目前乳房炎科学界严重缺乏的一个方面。然后将开发和提出新的分析方法来控制潜在的残留偏差，并提高乳房健康研究结果的有效性和可比性。这部分研究计划中强调的一般原则也应该对各种健康学科的研究非常有用。其次，将进行研究，进一步扩大我们对乳房炎病原体流行病学的了解。作为第一步，将对与临床乳腺炎复发相关的危险因素进行研究。这项研究的结果将产生更好地控制奶牛乳房炎所需的基础知识，并将通过降低与乳房炎相关的重要成本、改善奶牛的福利和减少抗生素的使用，对加拿大乳制品行业产生深远影响。

Mastitis, an inflammation of the mammary gland most often resulting from a bacterial infection, is a multi-faceted disease and is one of the most expensive dairy cow health problems. The estimated cost of mastitis for Canadian dairy producers is approximately $300 million per year. Mastitis reduces milk yield of dairy cows and affects animal welfare with clearly visible and measurable signs of sickness and discomfort. Furthermore, antibiotics treatments used to treat and prevent mastitis represent a very large proportion of the antibiotics used on Canadian dairies and constitute a risk of residues in the milk supply that could be a threat for public health. Finally, there is currently no gold standard test to diagnose intramammary infections (IMI) and this later aspect has important repercussions both in research and in practice.** The long term objectives of the current research program are to further improve our understanding of mastitis pathogens epidemiology and to develop novel tools for monitoring IMI dynamic on dairies. We first propose to quantitatively evaluate the effect of different sampling protocols on the validity of the results commonly presented in udder health research. This first objective will allow the definition of clear sampling strategy guidelines for longitudinal udder health research, an aspect that is currently cruelly missing to the mastitis scientific community. Novel analytical methods will then be developed and proposed to control potential remaining biases and improve the validity and comparability of udder health research results. The general principles highlighted in this part of the research program should also be very useful for research in various health disciplines. Secondly, research will be conducted to further extend our understanding of mastitis pathogens epidemiology. As a first step, research on risk factors associated with recurrence of clinical mastitis will be conducted. Results from this study will generate the fundamental knowledge needed to better control mastitis on dairies and will have a profound impact on the Canadian dairy industry by mitigating the important costs associated with mastitis, by improving welfare of dairy cows, and by reducing the use of antibiotics.