该实验的动机是需要了解延迟第一次初乳收集对山羊初乳中免疫球蛋白G(IgG)浓度的影响,解决了针对山羊的研究中的差距,尽管它在奶牛养殖中具有重要意义。同时,我们检查了初乳IgG之间的关系,总蛋白(TP)和白利糖度值。从56只Saanen山羊中收集了两个初乳样本,每个乳房的一半。第一个样本是在出生后立即从右乳头收集的,和第二个样本是从左乳头收集在一个预定的产后间隔:0,4-6,8-10,或12-14小时产后,每个时间间隔包括14只山羊。通过ELISA测定初乳IgG,白利糖度是用数字折射仪测定的,用Bradford蛋白法测定TP。Sperman的相关性和Lin的一致性相关系数用于确定关联的方向和强度,并评估方法之间的一致性(预测精度)。分别。接收器操作员特征分析用于确定白利糖度和TP阈值,以使用几种截止值(20、30、40和50g/LIgG)预测优质初乳。初乳IgG的平均值(±SD),白利糖度,TP为54±22.6g/L,22±5.0%,和12±2.8g/dL,分别。统计分析没有提供证据表明首次采集时间(产后14小时)有显著影响,在IgG上,白利糖度,和TP。白利糖度和IgG值表现出高度的相关性(r=0.89-90)和一致性(ρc=0.89-90),表明两种测量之间有很强和可靠的关系。≥20、30、40和50gIgG/L样本的患病率分别为96、88、71和54%,分别。预测IgG≥20、30、40和50g/LIgG的最佳白利糖度和TP阈值分别为13.8、17.5、20.1和22.5%,和6.8、9.3、10.8和11.1g/dL,分别。增加IgG阈值导致使用白利糖度或TP值估计初乳IgG的较低灵敏度但较高特异性。本研究结果表明,延迟初乳收集至产后14小时不会导致初乳IgG浓度的决定性变化,白利糖度值,或总蛋白质水平。我们的结果还证实了Brix折光法作为估算山羊初乳中IgG浓度的农场工具的可靠性。这些结果与集约化乳制品系统特别相关,提供见解以增强初乳管理和任务优先级,尤其是在热闹的开玩笑时期。
This experiment was motivated by the need to understand the impacts of delaying the first colostrum collection on immunoglobulin G (IgG) concentrations in goat colostrum, addressing a gap in caprine-specific research, despite its significance in dairy farming. Concurrently, we examined the relationship between colostral IgG, total protein (TP) and Brix values. Two colostrum samples were collected from 56 Saanen goats, one from each udder half. The first sample was collected from the right teat immediately postbirth, and the second sample was collected from the left teat at one of the predetermined postpartum intervals: 0, 4-6, 8-10, or 12-14 h postpartum, each time interval comprising 14 goats. Colostral IgG was determined by ELISA, Brix was determined by digital refractometry, and TP was determined by the Bradford protein method. Sperman\'s correlations and Lin\'s concordance correlation coefficient were used to determine the direction and strength of the association and to assess agreement (prediction accuracy) between methods, respectively. Receiver operator characteristic analysis was used to determine Brix and TP thresholds for predicting good-quality colostrum using several cut-offs (20, 30, 40, and 50 g/L IgG). Mean (± SD) for colostral IgG, Brix, and TP were 54 ± 22.6 g/L, 22 ± 5.0%, and 12 ± 2.8 g/dL, respectively. The statistical analysis did not provide evidence of a significant impact of time of first collection (up to 14 h postpartum), on IgG, Brix, and TP. Brix and IgG values exhibited both a high degree of correlation (r = 0.89-90) and concordance (ρc = 0.89-90), indicating a strong and reliable relationship between the two measurements. The prevalence of samples ≥ 20, 30, 40, and 50 g of IgG/L were 96, 88, 71, and 54%, respectively. Optimal Brix and TP thresholds predicting IgG ≥ 20, 30, 40, and 50 g/L IgG were 13.8, 17.5, 20.1, and 22.5%, and 6.8, 9.3, 10.8, and 11.1 g/dL, respectively. Increasing the IgG threshold resulted in lower sensitivity but higher specificity for estimating colostral IgG using Brix or TP values. The present findings indicate that delaying the first colostrum collection up to 14 h postpartum did not result in conclusive changes in colostral IgG concentration, Brix values, or total protein levels. Our results also confirm the reliability of Brix refractometry as an on-farm tool for estimating IgG concentrations in goat colostrum. These results are particularly relevant to intensive dairy systems, offering insights to enhance colostrum management and task prioritisation, especially during the bustling kidding periods.