Supplemental Table S1. Effects of calcium ammonium nitrate fed to dairy cows on nutrient intake and digestibility, milk quality, microbial protein synthesis, and ruminal fermentation parameters.

Effect of calcium ammonium nitrate supplementation on plasma urea nitrogen (PUN) before (0 h) and after (4 h) feeding in lactating Holstein dairy cows. P-values: Treat = 0.64; Time <0.01; Treat × time = 0.28; Linear = 0.37; Quadratic = 0.91; SEM = 1.43. URE: control group (without nitrate); CAN15: 15 g of calcium ammonium nitrate per kg of DM; CAN30: 30 g of calcium ammonium nitrate per kg of DM.

硝酸铵钙补充剂对泌乳荷斯坦奶牛饲喂前（0 h）及饲喂后（4 h）血浆尿素氮（plasma urea nitrogen, PUN）水平的影响。显著性检验的P值结果如下：处理组效应（Treat）=0.64；时间效应（Time）<0.01；处理与时间交互效应（Treat × time）=0.28；线性效应（Linear）=0.37；二次效应（Quadratic）=0.91；标准误（standard error of the mean, SEM）=1.43。其中，URE组为对照组（不添加硝酸盐）；CAN15组为每千克干物质（dry matter, DM）添加15 g硝酸铵钙的处理组；CAN30组为每千克干物质（dry matter, DM）添加30 g硝酸铵钙的处理组。