Abstract The objective of this trial was to determine the amount of alfalfa hay (AH) in low forage diets that could be replaced with dried corn gluten feed (DCGF) without negatively altering eating behaviour, ruminal fermentation, nutrient digestibility, and performance of lactating dairy cows. Eight multiparous Holstein cows were used in a replicated 4 × 4 Latin square design experiment. Treatments included (dry matter [DM] basis): 18.81% AH without DCGF (0DCGF,); 12.53% AH and 6.26% DCGF (6DCGF); 6.26% AH and 12.53% DCGF (12DCGF); and 0% AH and 18.81% DCGF (18 DCGF). Diet particle size and physically effective neutral detergent fibre declined linearly (p < .001) as DCGF replaced AH resulting in a linear decrease (p < .001) in time (min/d) spent eating, ruminating, and chewing. As DCGF replaced AH, ruminal pH decreased linearly (p = .003) and total VFA concentrations increased linearly (p = .02) tending to be highest (p = .062) for 12DCGF. Ruminal acetate and butyrate, and plasma β-hydroxybutyrate concentrations declined linearly (p = .001) whereas ruminal propionate concentration increased linearly (p = .001) as DCGF increased. Dry matter intake (DMI; p = .001) and nutrient digestibility increased linearly (p < .05) and tended to be greatest (p < .10) for 12DCGF. Milk yield (MY; p = .016) and protein yield (p = .001) increased linearly, but milk fat yield declined as DCGF replaced 6 and 12% of AH and decreased more when DCGF replaced all AH resulting in a quadratic response (p = .041). Results of this trial suggest that replacing 12% of the AH with DCGF increases MY because of higher DMI and nutrient digestibility, but replacing all of the AH with DCGF reduces milk fat yield and dairy efficiency. Highlights DCGF can replace AH to improve nutrient digestibility and milk yield. Improvements in nutrient digestibility when DCGF replaces AH potentially reduce total waste production of dairy cows. Completely replacing AH with DCGF in low forage diets reduces milk fat yield due to change in ruminal fermentation.

中文翻译：

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用干玉米蛋白饲料代替苜蓿干草会改变泌乳奶牛的采食行为、营养物质消化率和生产性能

摘要 本试验的目的是确定低草料日粮中苜蓿干草 (AH) 的含量，这些日粮可以用干玉米蛋白饲料 (DCGF) 代替，而不会对采食行为、瘤胃发酵、营养物质消化率和泌乳乳品的性能产生负面影响。奶牛。在重复的 4 × 4 拉丁方设计实验中使用了八头经产荷斯坦奶牛。包括的处理（基于干物质 [DM]）：18.81% AH，不含 DCGF (0DCGF)；12.53% AH 和 6.26% DCGF (6DCGF)；6.26% AH 和 12.53% DCGF (12DCGF)；0% AH 和 18.81% DCGF (18 DCGF)。随着 DCGF 取代 AH，饮食粒度和物理有效的中性洗涤纤维呈线性下降 (p < .001)，导致进食、反刍和咀嚼时间 (min/d) 线性下降 (p < .001)。随着 DCGF 取代 AH，瘤胃 pH 值呈线性下降（p = . 003) 和总 VFA 浓度线性增加 (p = .02) 趋于最高 (p = .062) 12DCGF。瘤胃乙酸盐和丁酸盐以及血浆 β-羟基丁酸盐浓度线性下降 (p = .001)，而随着 DCGF 的增加，瘤胃丙酸盐浓度线性增加 (p = .001)。12DCGF 的干物质摄入量 (DMI; p = .001) 和养分消化率线性增加 (p < .05) 并且趋于最大 (p < .10)。牛奶产量 (MY; p = .016) 和蛋白质产量 (p = .001) 线性增加，但随着 DCGF 取代 AH 的 6% 和 12%，乳脂产量下降，当 DCGF 取代所有 AH 时，乳脂产量下降更多，导致二次响应（ p = .041）。该试验的结果表明，用 DCGF 代替 12% 的 AH 会增加 MY，因为更高的 DMI 和养分消化率，但是用 DCGF 代替所有的 AH 会降低乳脂产量和乳制品效率。亮点 DCGF 可替代 AH 以提高养分消化率和产奶量。当 DCGF 替代 AH 时，营养物质消化率的改善可能会减少奶牛的总废物产生。由于瘤胃发酵的变化，在低草料日粮中用 DCGF 完全替代 AH 会降低乳脂产量。