Chestnut A B, Berger L L, Fahey G C
J Anim Sci. 1987 Mar;64(3):842-54. doi: 10.2527/jas1987.643842x.
Tall fescue hay (H) supplemented with corn and urea (HU) or corn gluten meal (HCGM) and ammoniated tall fescue hay supplemented with corn (AH) or corn gluten meal (AHCGM) were fed to steers in two 4 X 4 Latin-square trials. Diets were fed to four Angus-Hereford steers (550 kg) at equal intakes in trial 1 and to four Hereford steers (350 kg) at ad libitum intakes in trial 2. Ammoniation reduced cell wall concentrations of p-coumaric acid and ferulic acid by 48 and 67%, respectively. Concentrations of other phenolics were also reduced. Apparent total tract digestibilities of vanillin, p-coumaric acid and ferulic acid were lower (P less than .05, .001 and .01, respectively) when nontreated hay was fed in trial 1, but were not different between hay types in trial 2. In trial 1, greater negative intestinal digestibilities of p-coumaric acid (P less than .001) and vanillin (P less than .05) occurred for steers fed HU and HCGM vs AH and AHCGM diets. Digestibilities of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were greater (P less than .001) for steers fed ammoniated hay diets in both trials and greater (P less than .05) for HCGM vs HU in trial 1. More than 96% of the NDF and ADF digested by steers in trial 1 was digested in the stomach. Intakes of digestible NDF and ADF, but not indigestible NDF or ADF, were higher (P less than .001) for steers fed AH and AHCGM in trial 2. In situ dry matter disappearance rate of ammoniated hay was greater (P less than .05) than that of nontreated hay, but rate of cotton thread disappearance from bags suspended in the rumen of steers fed the various diets was similar among treatments. In both trials, feeding ammoniated hay resulted in higher (P less than .05) ruminal concentrations of acetate and higher (P less than 0.05) acetate:propionate ratios. Ruminal liquid dilution rates were lower (P less than .05) for steers fed AH and AHCGM in trial 1, but were not different in trial 2. Ruminal dry matter concentration and solids dilution rate were not affected by diet in either trial. The results are interpreted to indicate that increased intake of ammoniated hay is a result of increased rate and extent of fiber digestion.
在两项4×4拉丁方试验中，给阉牛饲喂高羊茅干草（H），分别添加玉米和尿素（HU）或玉米蛋白粉（HCGM），以及氨化高羊茅干草分别添加玉米（AH）或玉米蛋白粉（AHCGM）。试验1中，以等量给4头安格斯-赫里福德阉牛（550千克）饲喂这些日粮；试验2中，以随意采食方式给4头赫里福德阉牛（350千克）饲喂。氨化分别使对香豆酸和阿魏酸的细胞壁浓度降低了48%和67%。其他酚类物质的浓度也有所降低。在试验1中，饲喂未处理干草时，香草醛、对香豆酸和阿魏酸的表观全肠道消化率较低（分别为P＜0.05、P＜0.001和P＜0.01），但在试验2中，不同类型干草之间的消化率没有差异。在试验1中，与饲喂AH和AHCGM日粮的阉牛相比，饲喂HU和HCGM日粮的阉牛对香豆酸（P＜0.001）和香草醛（P＜0.05）的负肠道消化率更高。在两项试验中，饲喂氨化干草日粮的阉牛中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）的消化率更高（P＜0.001），在试验1中，饲喂HCGM日粮的阉牛的NDF和ADF消化率比饲喂HU日粮的更高（P＜0.05）。试验1中，阉牛消化的NDF和ADF超过96%是在胃中消化的。试验2中，饲喂AH和AHCGM日粮的阉牛可消化NDF和ADF的摄入量较高（P＜0.001），但不可消化NDF或ADF的摄入量并非如此。氨化干草的原位干物质消失率比未处理干草更高（P＜0.05），但在饲喂不同日粮的阉牛瘤胃中悬挂的袋子里棉线的消失率在各处理之间相似。在两项试验中，饲喂氨化干草导致瘤胃中乙酸盐浓度更高（P＜0.05），乙酸盐:丙酸盐比例更高（P＜0.05）。试验1中，饲喂AH和AHCGM日粮的阉牛瘤胃液稀释率较低（P＜0.05），但在试验2中没有差异。在两项试验中，日粮对瘤胃干物质浓度和固体稀释率均无影响。这些结果表明，氨化干草摄入量增加是纤维消化速率和程度提高的结果。
