Department of Population Medicine, University of Guelph, Guelph, ON, Canada, N1G 2W1.
Department of Population Medicine, University of Guelph, Guelph, ON, Canada, N1G 2W1.
J Dairy Sci. 2020 Apr;103(4):3521-3528. doi: 10.3168/jds.2019-17397. Epub 2020 Feb 7.
This retrospective cross-sectional study was designed to identify risk factors associated with failed transfer of passive immunity (FTPI) and to determine differences in colostrum management between male and female dairy calves. Research technicians visited a total of 16 commercial dairy farms weekly. For each calf born on these farms, the farm personnel completed a birth record to document the colostrum management practices provided, level of calving assistance, calf sex, and time of birth. On the weekly visits to the farms, the technicians collected blood from calves that were 1 to 7 d of age. Serum was separated via centrifugation and the concentration of serum total protein (STP) was determined using a digital refractometer. Failed transfer of passive immunity was defined as calves having an STP of <5.2 g/dL. Data were available for 1,778 calves aged 1 to 7 d. Several differences were observed with respect to how male and female calves were managed. Male calves were more likely to receive a lower volume of colostrum, have colostrum delivered using a nipple bottle followed by an esophageal tube feeder, be fed pooled colostrum, and receive fresh colostrum rather than frozen colostrum relative to female calves. Serum total protein (STP) ranged from 3.6 to 9.7 g/dL with a mean of 5.7 g/dL (standard deviation, 0.7 g/dL) and 21.1% of the calves had FTPI. Using a mixed linear regression model, we identified that a calf being male (-0.14 g/dL), being delivered by a hard pull (-0.23 g/dL), and receiving the first feeding colostrum from a combination of a nipple bottle followed by an esophageal tube feeder (-0.12 g/dL) were associated with a lower concentration of STP. Feeding 6 L or more of colostrum in the first 24 h of life was associated with a 0.14 g/dL higher concentration of STP compared with feeding <3.9 L of colostrum. For FTPI, being delivered by a hard pull [odds ratio (OR) 2.21] and receiving the first feeding colostrum from a nipple bottle followed by an esophageal tube feeder (OR 1.83) were associated with higher odds of FTPI. Feeding >6 L of colostrum in the first 24 h of life was associated with a reduced odds (OR 0.65) of FTPI compared with feeding <3.9 L of colostrum. This study highlights the importance of certain management practices in reducing FTPI incidence and identifies discrepancies in colostrum management between male and female dairy calves.
本回顾性横断面研究旨在确定与被动免疫传递失败（FTPI）相关的风险因素，并确定公奶牛和母奶牛在初乳管理方面的差异。研究技术人员每周总共访问 16 家商业奶牛场。对于这些农场出生的每头小牛，农场人员都会填写一份出生记录，记录提供的初乳管理实践、助产程度、小牛性别和出生时间。在每周对农场的访问中，技术人员从 1 至 7 日龄的小牛中采集血液。通过离心分离血清，并使用数字折射仪确定血清总蛋白（STP）的浓度。FTPI 定义为血清总蛋白（STP）<5.2 g/dL 的小牛。共有 1778 头 1 至 7 日龄的小牛的数据可用。在公奶牛和母奶牛的管理方面，观察到了一些差异。公奶牛更有可能接受较少的初乳量，使用奶嘴瓶和食管管饲器提供初乳，接受混合初乳，以及接受新鲜初乳而不是冷冻初乳，而母奶牛则不是这样。血清总蛋白（STP）范围为 3.6 至 9.7 g/dL，平均值为 5.7 g/dL（标准差为 0.7 g/dL），21.1%的小牛出现 FTPI。使用混合线性回归模型，我们发现小牛为雄性（-0.14 g/dL）、硬拉分娩（-0.23 g/dL）以及第一口初乳由奶嘴瓶和食管管饲器联合喂养（-0.12 g/dL）与 STP 浓度较低相关。与摄入<3.9 L 的初乳相比，在生命的头 24 小时内摄入 6 L 或更多的初乳与 STP 浓度升高 0.14 g/dL 相关。FTPI 方面，硬拉分娩（比值比[OR]2.21）和第一口初乳由奶嘴瓶和食管管饲器联合喂养（OR 1.83）与 FTPI 风险增加相关。与摄入<3.9 L 的初乳相比，在生命的头 24 小时内摄入>6 L 的初乳与 FTPI 风险降低（OR 0.65）相关。本研究强调了某些管理实践在降低 FTPI 发生率方面的重要性，并确定了公奶牛和母奶牛在初乳管理方面的差异。
