【作者】 赵遵阳；

【导师】 孟庆翔；

【作者基本信息】 中国农业大学 ， 动物营养与饲料科学， 2003， 硕士

【摘要】 本研究包括以下三个试验：1)不同品种和成熟期的高油玉米秸秆作为青贮原料的营养价值比较研究；2)不同品种(高油、普通、青贮专用)玉米秸秆青贮的营养价值比较研究；3)高油玉米青贮饲喂肉牛的生产性能的研究。 试验一对高油玉米品种(HOC115、HOC298、HOC601和HOC647)在子粒4／4乳线期秸秆青贮青贮前后微生物数量及各高油玉米品种不同成熟期(子粒2／4乳线、3／4乳线和4／4乳线期)秸秆青贮的发酵品质、化学成分和消化性能进行了研究。4／4乳线期各品种秸秆青贮前后乳酸菌及酵母菌数量差异显著(P＜0.01)。随子粒成熟期延长，HOC115和HOC601秸秆青贮发酵品质下降，HOC298和HOC647各期秸秆青贮均发酵良好。HOC115和HOC601随子粒成熟期延长，其秸秆青贮中水溶性糖含量虽略有增加，但由于粗蛋白(P＜0.05)和粗脂肪(P＜0.01)含量的下降以及纤维组分的增加，其体外发酵48h干物质消化率(P＜0.01)和细胞壁消化率(P＜0.01)均明显下降，造成了营养价值的下降，其青贮的最佳成熟期应在2／4乳线期，最迟不超过3／4乳线期。HOC298和HOC647由于成熟后期秸秆青贮中水溶性糖含量迅速增加，纤维组分含量下降，其体外发酵48h干物质消化率(P＜0.01)和细胞壁消化率(P＜0.01)均明显增加，秸秆品质提高，其青贮的最佳成熟期可适当延长至子粒3／4乳线期和4／4乳线期。 试验二对HOC115、普通品种3138和青贮专用品种秸秆青贮的营养价值进行了比较。4／4乳线期青贮前后各品种秸秆乳酸菌及酵母菌数量差异显著(P＜0.01)。随子粒成熟期延长，3138秸秆青贮发酵品质下降，秸秆中水溶性糖(P＜0.01)、粗蛋白(P＜0.05)、粗脂肪(P＜0.01)及淀粉(P＜0.01)含量随成熟期线性下降，NDF、ADF和木质素(P＜0.01)线性升高，造成其秸秆干物质消化率(P＜0.01)和细胞壁消化率(P＜0.01)明显下降，其秸秆青贮的最佳成熟期应在2／4乳线期。青贮专用品种各期秸秆青贮均发酵良好，成熟后期秸秆中水溶性糖含量增加，纤维组分含量下降，其体外发酵48h干物质消化率(P＜0.01)明显升高，其秸秆青贮的最佳成熟期应在3／4乳线期或4／4乳线期。2／4乳线期各品种秸秆青贮的营养价值相当，但成熟后期青贮专用品种优势明显。 试验三利用60头晋南黄牛阉公牛进行生长试验和尼龙袋消化试验，研究高油115及普通品种唐抗2整株青贮饲喂生长牛的生产性能及其瘤胃干物质和纤维消化率。试验发现，高油115整株青贮24h和48h的尼龙袋干物质和纤维消化率明显低于唐抗2。但高油115整株青贮的干物质采食量明显高于唐抗2(P＜0.01)，在日增重及饲料效率方面二者无明显差异(P＞0.05)。更多还原

【Abstract】 Three experiments were conducted to determine the effect of interaction between variety and maturity stage of kernels on silage fermentation characteristics of high oil com (HOC) stalks and on their feeding values to growing cattle. The treatments included corn variety (HOC115, HOC601, HOC647, normal 3138 or specific silage corn variety) and maturity stage of kernels (2/4,3/4 and 4/4 milk line; ML).In Experiments 1, microorganism counts in pre- and post-ensiling corn stalks of 4/4 ML maturity stage, stalk silage fermentation characteristics, chemical composition and in vitro digestibility of four high oil com varieties (HOC 115, HOC298, HOC601 and HOC647) were determined. Significant difference in the number of Lactobacillus and yeasts of pre- and post-ensiling stalks was found among the four varieties. With the latest maturity stage, there was a higher pH value and lower lactic acid concentration for HOC115 and HOC601. In contrast, increasing maturity stage of kernels of HOC 298 and HOC 647 resulted in a declined pH values and an increased lactic acid concentration. With advancing maturities, there were a tendency in an increased content of WSC (P<0.01), decreased contents of CP and ether extract (P<0.01), with exception of CP of 298 (PXX05), which had no significant change (P>0.05) with maturity stage. Advancing maturity stage of kernels significantly increased starch content (P<0.05) of stalk silage of HOC115, HOC 298 and HOC 647. As progressive maturity of kernels, the content of fiber fraction (NDF, ADF and lignin) of stalk silage was increased (P<0.01) for HOC115 and HOC601, but not for HOC298 and HOC647. The content of calcium of stalk silage had a decreased tendency with advancing maturity stage of com kernels, but the content of phosphate was less affected by the maturity stage. With progressive maturity of stalk silage, the DM and NDF digestibility, 48 h gas production and gas production rate (P<0.01) were decreased for HOC115 and HOC601, but increased (P<0.01) for HOC298 and HOC647.The purpose of Experiment 2 was to compare the nutritional value of stalk silage of HOC 115, normal corn variety 3138 and a specific silage corn variety. Significant difference was found for the count of Lactobacillus and yeasts (P<0.01) in pre- and post-ensiling stalks among the three varieties. For the variety of 3138, with increasing maturity, there was a declined lactic acid concentration and a increased pH value. Less contents of WSC, ether extract, starch (P<0.01) and crude protein (P<0.05), but higher contents of NDF, ADF and lignin (P<0.01) were also found with progressive maturity stage of com kernels. Advancing the maturity stage of com kernels seemed to decrease (P<0.05) phosphorus content of the stalk silage, but not affect the calcium content (P>0.05). In contrast to 3138, the specific silage com variety showed more contents of WSC and starch (P<0.01), less contents of CP and ether extract (P<0.05) with advanced maturity stage of com kernels. As maturity increased, the digestibility of DM and NDF, 48 h gas production and gas produced rate (P<0.01) decreased gradually for 3138, but quadraticly increased for the specific silage corn variety.In Experiment 3, a growing trial using 60 Jinnan yellow steers and an in situ study were conducted to investigate the effect of whole-plant silage of HOC115 and Tangkang No.2 (another normal corn variety) on growing performance and their dry matter and fiber digestibility. The result was that the digestibility of DM, NDF and ADF of HOC115 was much lower (P<0.05) than Tangkang No.2, whereas DM intake of the silage of HOC115 was much higher (P<0.01) than Tangkang No.2. However, there was no significant difference (P>0.05) in daily gain rate and feed conversion between the two silage diets.更多还原