PREVALENCE OF THE MAIN DIGESTIVE AND RESPIRATORY PATHOGENS IN DAIRY PREWEANED CALVES IN QUÉBEC

肺炎和腹泻是乳牛中最常见的两种疾病。它们造成重大的经济损失，包括治疗费用、死亡以及对生长和未来牛奶产量的不利影响。它们也是抗菌药物使用的重要原因。小牛群体住房和群体喂养策略越来越多地被植入到曲海岬的奶牛群中。然而，人们的看法是，这些疾病，主要是肺炎，在这种饲养系统中更为普遍。令人惊讶的是，关于与这些疾病相关的不同已知病原体在青海和加拿大的奶牛中流行的数据很少，特别是在这种饲养系统中。本研究的目的是：(i)描述这些病原体在奶牛中的流行情况，（ii）比较实施群体饲养和群体喂养前后的流行情况，以及（iii）评估呼吸道病原体的抗微生物药物耐药性。根据这项研究的结果，将有可能确定新的预防战略，包括新的疫苗接种方案，这将有助于生产者更好地在其畜群中预防这些疾病。在不久的将来，这些新的疫苗接种方案的验证很可能成为合作研究与发展基金的一项新申请

Pneumonia and diarrhea are the two most prevalent diseases in dairy calves. They cause important economical losses from treatment costs, deaths and detrimental impacts on growth and future milk production. They are also an important cause of antimicrobial uses. Calf group housing and group feeding strategies are increasingly being implanted in dairy herds in Québec. However, the perception is that these diseases, mainly pneumonia, are more prevalent in such raising system. Surprisingly, very few data are available on the prevalence of the different known pathogens associated with these diseases in dairy calves in Québec and Canada, and particularly in such raising systems. The objective of this study is to (i) describe the prevalence of these pathogens in dairy calves, (ii) to compare this prevalence before and after the implementation of group housing and group feeding and (iii) to evaluate the antimicrobial drug resistance of the respiratory pathogens. Based on the results of this study, it will be possible to identify new prevention strategies, including new vaccination protocols, that will help producers better prevent these diseases in their herd. The validation of these new vaccination protocols is very likely to be a new application at the Collaborative Research and development Grant in a near future.**