Department of Animal Science, The Pennsylvania State University, University Park 16802.
Department of Animal Science, The Pennsylvania State University, University Park 16802.
J Dairy Sci. 2019 Mar;102(3):2068-2074. doi: 10.3168/jds.2018-15542. Epub 2019 Jan 17.
The objective of this study was to determine the effect of different durations of heat treatment on passive transfer of IgG from high-, medium- and low-quality colostrum. Colostrum was collected from The Pennsylvania State University dairy herd and divided by quality (high, medium, or low) based on colostrometer measurements. Colostrum was pooled by quality to create 3 unique batches. Each batch was further divided in thirds as follows: frozen to be fed without heat treatment, heated at 60°C for 30 min, or heated at 60°C for 60 min. Colostrum samples from each treatment were collected and analyzed for standard plate count, gram-negative noncoliforms, coliforms, and total IgG concentration. Serum samples were collected from 108 Holstein calves before feeding colostrum and 24 h after birth. Blood samples were analyzed for total protein, total IgG, and hematocrit. Colostrum quality (high, medium, or low), heat treatment (unheated, 60°C for 30 min or, 60°C for 60 min), and their interaction were analyzed as fixed effects, with calf sex included as a random block effect. Colostrum IgG was different between quality groups (92.5, 59.4, and 48.1 mg/mL of IgG). Heating colostrum reduced IgG concentration compared with the control by 9% when heated for 30 min and by 12% when heated for 60 min. Colostrum heated for 60 min had a lower standard plate count than colostrum heated for 30 min or not heated (1.8, 2.0, and 3.6 log cfu/mL, respectively). Serum IgG concentration at 24 h increased as colostrum quality increased (18.0, 22.2, and 24.8 mg/mL) and tended to increase as heat treatment time increased (19.7, 20.3, and 25.0 mg/mL of IgG). Apparent efficiency of IgG absorption was greater in calves that received medium-quality colostrum compared with calves fed high-quality colostrum (38.1 and 25.0%, respectively). These results suggest an upper limit may exist to the amount of IgG absorption in a given time period and that medium- or high-quality colostrum yields similar blood IgG concentration given the same volume of intake.
本研究旨在确定不同热处理时间对高、中、低质量初乳中 IgG 被动传递的影响。初乳来自宾夕法尼亚州立大学奶牛场，根据乳质计的测量结果按质量（高、中、低）进行分组。将初乳按质量分组，形成 3 个独特的批次。每个批次再分为三分之一，如下所示：冷冻处理，不进行热处理；加热至 60°C 30 分钟；或加热至 60°C 60 分钟。收集每个处理的初乳样本并分析标准平板计数、革兰氏阴性非大肠菌、大肠菌和总 IgG 浓度。在喂初乳前和出生后 24 小时从 108 头荷斯坦小牛采集血清样本。分析血清样本的总蛋白、总 IgG 和红细胞压积。初乳质量（高、中、低）、热处理（未加热、60°C 加热 30 分钟或 60°C 加热 60 分钟）及其相互作用作为固定效应进行分析，小牛性别作为随机区组效应进行分析。初乳 IgG 浓度在质量组间存在差异（92.5、59.4 和 48.1mg/mL 的 IgG）。与对照组相比，30 分钟加热使 IgG 浓度降低 9%，60 分钟加热使 IgG 浓度降低 12%。与 30 分钟加热或不加热的初乳相比，60 分钟加热的初乳标准平板计数更低（分别为 1.8、2.0 和 3.6 log cfu/mL）。24 小时时，血清 IgG 浓度随初乳质量的增加而增加（18.0、22.2 和 24.8mg/mL），并随热处理时间的增加而呈上升趋势（19.7、20.3 和 25.0mg/mL 的 IgG）。与接受高质量初乳的小牛相比，接受中等质量初乳的小牛 IgG 吸收效率更高（分别为 38.1%和 25.0%）。这些结果表明，在给定的时间内，IgG 吸收量可能存在上限，并且在摄入相同体积的情况下，中等或高质量的初乳可产生相似的血液 IgG 浓度。
