Corn gluten feed (CGF) is a co-product of wet milling that can replace energy or fiber ingredients in dairy cow rations. The present meta-analysis examines how inclusion of CGF can affect dry matter intake (DMI), milk yield (MY), milk components, and ruminal fermentation parameters. A literature search was conducted to identify papers published from 1990 to 2018. Effect size for all parameters was calculated as standardized mean difference with a 95% confidence interval. Heterogeneity was determined using Q test and I² statistic, while meta-regression was used to examine factors influencing heterogeneity. Results indicate that feeding CGF increased the effect size for DMI and MY. No differences were observed for effect size for percentage milk fat or protein; however, increases were observed in the effect size for milk fat yield, milk protein yield, milk lactose percentage, and milk lactose yield. Ruminal fermentation parameters revealed a decrease in the effect size for pH and acetate and an increase for propionate. No differences were observed in the effect size for total VFA or butyrate. The Q test demonstrated heterogeneity (P < 0.1) for MY, MFP, and pH. The results indicate differences in forage intake between groups receiving CGF and control as an important factor contributing to heterogeneity for DMI, MFP, and pH. It can be concluded from this meta-analysis that in addition to increased DMI, inclusion of CGF in cow diets increases MY and improves milk components. Furthermore, inclusion of CGF in the diet lowers ruminal pH while decreasing acetate and increasing propionate contents.

玉米面筋饲料（CGF）是湿磨的副产品，可以替代奶牛口粮中的能量或纤维成分。本荟萃分析检查了CGF的加入如何影响干物质摄入量（DMI），牛奶产量（MY），牛奶成分和瘤胃发酵参数。进行文献检索以鉴定1990年至2018年发表的论文。所有参数的效应大小以95％置信区间的标准化均值差计算。使用Q检验和I ²确定异质性统计量，而使用元回归分析影响异质性的因素。结果表明，饲喂CGF会增加DMI和MY的作用范围。牛奶脂肪或蛋白质百分比的效应量未见差异；然而，观察到乳脂产量，乳蛋白产量，乳乳糖百分比和乳乳糖产量的作用大小增加。瘤胃发酵参数显示，pH和乙酸盐的作用大小减小，丙酸根的作用大小增加。总VFA或丁酸酯的效应量未见差异。的Q测试表明异质性（P MY，MFP和pH值<0.1）。结果表明，接受CGF和对照组的饲料摄入量之间的差异是导致DMI，MFP和pH异质性的重要因素。从这项荟萃分析可以得出结论，除了增加DMI之外，在奶牛日粮中添加CGF还可以提高MY并改善牛奶成分。此外，在日粮中添加CGF可以降低瘤胃pH值，同时降低乙酸盐含量并增加丙酸酯含量。