Cameron M G, Fahey G C, Clark J H, Merchen N R, Berger L L
Dept. of Anim. Sci., University of Illinois, Urbana 61801.
J Anim Sci. 1991 Apr;69(4):1775-87. doi: 10.2527/1991.6941775x.
The objective of this experiment was to determine the effects of feeding different levels of alkaline hydrogen peroxide-treated wheat straw (AHP-WS) in the diet on feed intake, nutrient digestion, ruminal fermentation, and production responses in mid-lactation dairy cows. Eight Holstein cows, averaging 147 d postpartum, were used in two replications of a 4 x 4 Latin square design. Complete mixed diets consisted of 70% forage and 30% concentrate (DM basis) with various levels of AHP-WS, alfalfa haylage, and corn silage as forage sources. Treatments contained 0 (control), 20.0, 40.1, or 60.0% AHP-WS in the diet. A quadratic effect (P = .08) of AHP-WS level on DMI was noted, with values of 2.16, 22.3, 20.8, and 18.9 kg/d for the control, 20.0, 40.1, and 60.0% AHP-WS treatments, respectively. Apparent digestibilities of DM, OM, CP, and ADF were not affected (P greater than .10) by replacing haylage and corn silage with increasing amounts of AHP-WS in the diet, but there was a linear increase (P = .03) in NDF digestibility (44% for control vs 59% for the 60.0% AHP-WS diet) and a parallel decrease (P less than .05) in cell content digestibility (82 vs 70% for these two diets). Yields of milk and 4% fat-corrected milk (FCM) were decreased (quadratic; P = .0001) as the level of AHP-WS increased in the diet. The addition of AHP-WS to the diet decreased the milk fat percentage from 3.72 to 3.60% (quadratic; P = .05) and decreased milk protein percentage from 3.27 to 3.13% (linear; P = .0001). Cows fed the higher levels of AHP-WS had linear increases (P = .0001) in ruminal concentrations of total VFA (128.0 mM for control vs 136.0 mM for the 60.0% AHP-WS treatment) and molar proportion of acetate, resulting in a quadratic effect (P less than .0001) on the acetate:propionate ratio. These data indicate that feeding the 40.1 and 60.0% AHP-WS diets lowered digestible DM and OM intakes, which resulted in reduced 4% FCM yield as nutrient intakes were decreased compared with cows fed the 20.0% AHP-WS diet or the control diet containing alfalfa haylage and corn silage. Although substituting AHP-WS for haylage and corn silage increased NDF digestibility and tended to increase digestible NDF intake, milk production was depressed because digestible DMI decreased.
本试验旨在确定在泌乳中期奶牛日粮中饲喂不同水平的碱性过氧化氢处理麦秸（AHP-WS）对采食量、养分消化率、瘤胃发酵及生产性能的影响。选用8头平均产后147天的荷斯坦奶牛，采用4×4拉丁方设计，进行2次重复试验。全混合日粮由70%的粗饲料和30%的精饲料（干物质基础）组成，粗饲料来源为不同水平的AHP-WS、苜蓿青贮和玉米青贮。处理组日粮中AHP-WS的含量分别为0（对照组）、20.0%、40.1%或60.0%。AHP-WS水平对干物质采食量（DMI）有二次效应（P = 0.08），对照组、20.0%、40.1%和60.0% AHP-WS处理组的DMI分别为2.16、22.3、20.8和18.9 kg/d。日粮中用AHP-WS替代青贮苜蓿和玉米青贮，干物质（DM）、有机物（OM）、粗蛋白（CP）和酸性洗涤纤维（ADF）的表观消化率不受影响（P＞0.10），但中性洗涤纤维（NDF）消化率呈线性增加（P = 0.03）（对照组为44%，60.0% AHP-WS日粮组为59%），细胞内容物消化率呈平行下降（P＜0.05）（这两种日粮分别为82%和70%）。随着日粮中AHP-WS水平的增加，牛奶和4%乳脂校正乳（FCM）产量呈下降趋势（二次效应；P = 0.0001）。日粮中添加AHP-WS使乳脂率从3.72%降至3.60%（二次效应；P = 0.05），乳蛋白率从3.27%降至3.13%（线性效应；P = 0.0001）。饲喂较高水平AHP-WS的奶牛瘤胃中总挥发性脂肪酸（VFA）浓度呈线性增加（P = 0.0001）（对照组为128.0 mM，60.0% AHP-WS处理组为136.0 mM），乙酸摩尔比例增加，导致乙酸:丙酸比例呈二次效应（P＜0.0001）。这些数据表明，与饲喂20.0% AHP-WS日粮或含苜蓿青贮和玉米青贮的对照日粮的奶牛相比，饲喂40.1%和60.0% AHP-WS日粮降低了可消化干物质和有机物摄入量，由于养分摄入量减少，导致4% FCM产量降低。虽然用AHP-WS替代青贮苜蓿和玉米青贮提高了NDF消化率，并倾向于增加可消化NDF摄入量，但由于可消化DMI降低，牛奶产量下降。
