Montgomery S P, Drouillard J S, Titgemeyer E C, Sindt J J, Farran T B, Pike J N, Coetzer C M, Trater A M, Higgins J J
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-1600, USA.
J Anim Sci. 2004 Dec;82(12):3526-36. doi: 10.2527/2004.82123526x.
Twelve ruminally cannulated Jersey steers (BW = 534 kg) were used in an incomplete Latin square design experiment with a 2 x 2 factorial arrangement of treatments to determine the effects of wet corn gluten feed (WCGF) and total DMI level on diet digestibility and ruminal passage rate. Treatments consisted of diets formulated to contain (DM basis) steam-flaked corn, 20% coarsely ground alfalfa hay, and either 0 or 40% WCGF offered once daily for ad libitum consumption or limited to 1.6% of BW (DM basis). Two consecutive 24-d periods were used, each consisting of 18 d for adaptation, 4 d for collection, and a 2-d in situ period. Rumens of all steers were evacuated once daily at 0, 4, 8, and 12 h after feeding. Chromic oxide (10 g/[steer*d]) was fed as a digestibility marker, and steers were pulse-dosed with Yb-labeled alfalfa hay to measure ruminal particulate passage rate. Dacron bags containing 5 g of steam-flaked corn, WCGF, or ground (2-mm screen) alfalfa hay were placed into the rumens of all steers and removed after 3, 6, 12, or 48 h. Wet corn gluten feed increased percent apparent total-tract digestion of OM (P < 0.01), NDF (P < 0.01), and starch (P < 0.03), decreased (P < 0.01) ruminal total VFA concentration, increased (P < 0.01) ruminal NH3 concentration, and increased (P < 0.01) ruminal pH. Wet corn gluten feed also increased (P < 0.01) ruminal passage rate of Yb. Limit feeding decreased (P < 0.01) percent apparent total-tract digestion of both OM and NDF, ruminal total VFA concentration (P < 0.01), and ruminal fill (P < 0.01), but increased (P < 0.01) ruminal NH3 concentration. Apparent total-tract digestion of starch was not affected (P = 0.70) by level of DMI. A DMI level x hour interaction (P < 0.01) occurred for ruminal pH. Limit feeding increased ruminal pH before and 12 h after feeding, but decreased ruminal pH 4 h after feeding compared with diets offered ad libitum. A diet x DMI level interaction (P < 0.02) occurred for in situ degradation of alfalfa hay, with dietary addition of WCGF increasing (P < 0.02) the extent of in situ alfalfa hay degradation in steers fed for ad libitum consumption. This study suggests that WCGF increases OM and NDF digestion, and that limit feeding diets once daily might depress OM and NDF digestion, possibly due to decreased stability of the ruminal environment.
选用12头安装有瘤胃瘘管的泽西牛（体重=534千克），采用不完全拉丁方设计试验，处理采用2×2析因排列，以确定湿玉米蛋白粉（WCGF）和总干物质采食量（DMI）水平对日粮消化率和瘤胃通过率的影响。处理包括按干物质基础配制的日粮，含有蒸汽压片玉米、20%粗磨苜蓿干草，以及0或40%的WCGF，每天投喂一次，自由采食或限制在体重的1.6%（干物质基础）。采用两个连续的24天周期，每个周期包括18天适应期、4天收集期和2天原位期。所有试验牛的瘤胃在饲喂后0、4、8和12小时每天排空一次。饲喂氧化铬（10克/[头·天]）作为消化率标记物，并给试验牛脉冲投喂镱标记的苜蓿干草以测量瘤胃颗粒通过率。将装有5克蒸汽压片玉米、WCGF或磨碎（2毫米筛网）苜蓿干草的涤纶袋放入所有试验牛的瘤胃中，3、6、12或48小时后取出。湿玉米蛋白粉提高了有机物（P<0.01）、中性洗涤纤维（P<0.01）和淀粉（P<0.03）的表观全消化道消化率百分比，降低了（P<0.01）瘤胃总挥发性脂肪酸浓度，提高了（P<0.01）瘤胃氨浓度，并提高了（P<0.01）瘤胃pH值。湿玉米蛋白粉还提高了（P<0.01）镱的瘤胃通过率。限饲降低了（P<0.01）有机物和中性洗涤纤维的表观全消化道消化率百分比、瘤胃总挥发性脂肪酸浓度（P<0.01）和瘤胃充盈度（P<0.01），但提高了（P<0.01）瘤胃氨浓度。淀粉的表观全消化道消化率不受DMI水平的影响（P=0.70）。瘤胃pH值出现了DMI水平×小时的交互作用（P<0.01）。与自由采食的日粮相比，限饲提高了饲喂前和饲喂后12小时的瘤胃pH值，但降低了饲喂后4小时的瘤胃pH值。苜蓿干草的原位降解存在日粮×DMI水平的交互作用（P<0.02），日粮中添加WCGF提高了（P<0.02）自由采食的试验牛苜蓿干草原位降解程度。本研究表明，WCGF提高了有机物和中性洗涤纤维的消化率，并且每天限饲日粮可能会降低有机物和中性洗涤纤维的消化率，这可能是由于瘤胃环境稳定性降低所致。
