Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada.
PLoS One. 2022 Jun 29;17(6):e0269824. doi: 10.1371/journal.pone.0269824. eCollection 2022.
The objective of this scoping review was to describe the literature on the characteristics and management practices of colostrum feeding and their associations with the level of transfer of passive immunity (TPI) in dairy calves. Observational and experimental studies were searched in 5 electronic databases and 3 conference proceedings. Two reviewers independently screened primary studies, either analytic observational or experimental studies written in English. Studies on dairy or dual-purpose calves with passive immunity analyzed by blood sampling between 1 to 9 days of age were included. All studies had to compare at least one colostrum intervention or risk factor and their association with passive immunity. Of the 3,675 initially identified studies, 256 were included in this synthesis. One hundred and ninety-five were controlled trials, 57 were cohort studies, and 4 were cross-sectional studies. The effect of colostral quantity at first feeding was investigated in 30 controlled studies including studies that were comparable to each other. The effect of colostral quality was explored in 24 controlled studies with inconsistent criteria used to define the quality. The effect of the timing of first feeding of colostrum was investigated in 21 controlled studies, where the timing of feeding ranged widely from immediately after birth to 60 h of age. Only 4 controlled studies evaluated the relationship between bacterial load in the colostrum and TPI in dairy calves. Of the 256 total studies, 222 assessed blood IgG concentration while 107 measured blood total protein concentration. We identified a gap in knowledge on the association between passive immunity in dairy calves and the bacterial load in colostrum, or the timing of harvesting colostrum from the dam. A possible quantitative synthesis could be conducted among the studies that evaluated colostral quantity at the first feeding in relation to TPI in dairy calves.
本范围综述的目的是描述有关初乳喂养特征和管理实践的文献，并探讨其与奶牛犊牛被动免疫转移水平（TPI）的关系。在 5 个电子数据库和 3 次会议记录中搜索了观察性和实验性研究。两位审查员独立筛选了主要研究，这些研究是用英语撰写的分析性观察研究或实验研究。纳入了在 1 至 9 日龄之间通过血液采样分析被动免疫的奶牛或兼用牛犊的观察性和实验性研究。所有研究都必须比较至少一种初乳干预或风险因素及其与被动免疫的关系。在最初确定的 3675 项研究中，有 256 项被纳入本综述。其中 195 项为对照试验，57 项为队列研究，4 项为横断面研究。在 30 项包括相互可比研究的对照研究中，研究了初乳首次喂养时的初乳量的影响。在 24 项对照研究中探讨了初乳质量的影响，这些研究使用的定义质量的标准不一致。在 21 项对照研究中研究了首次喂养初乳的时间对 TPI 的影响，其中喂养时间从出生后立即到 60 小时不等。只有 4 项对照研究评估了奶牛犊牛初乳中细菌负荷与 TPI 之间的关系。在 256 项总研究中，222 项评估了血液 IgG 浓度，107 项测量了血液总蛋白浓度。我们发现，在奶牛犊牛被动免疫与初乳中的细菌负荷或从母牛中采集初乳的时间之间的关系方面，知识存在差距。可以对评估首次喂养初乳时的初乳量与奶牛犊牛 TPI 之间关系的研究进行定量综合分析。
