豆科牧草-全株玉米混贮比例对青贮饲用价值的影响

为探究不同豆科牧草与全株玉米不同混贮比例对提高青贮饲用价值的影响大小，本研究以2个豆科牧草品种（‘汾豆牧绿2号’和拉巴豆（Dolichos lablab））为主因素，以豆科牧草与全株玉米4种混贮比例（90%全株玉米+10%豆科牧草；80%全株玉米+20%豆科牧草；70%全株玉米+30%豆科牧草；100%豆科牧草）为副因素，对照组为100%全株玉米青贮（CK），共9个混贮处理，3次重复。青贮发酵完成后对其进行营养品质、发酵品质、瘤胃发酵参数、体外干物质降解率及产气量等指标的测定。结果表明：1）营养品质方面：100%‘汾豆牧绿2号’青贮的干物质（DM）最低，酸性洗涤纤维（ADF）、中性洗涤纤维（NDF）和粗蛋白（CP）含量最高；拉巴豆青贮的粗脂肪（EE）显著高于‘汾豆牧绿2号’（P<0.05）；100%全株玉米青贮的NDF、ADF和CP最低，EE最高。2）发酵品质方面：100%‘汾豆牧绿2号’处理下青贮的pH和氨氮（AN）显著高于其他处理（P<0.05）；100%拉巴豆处理下青贮乙酸（AA）最低；100%全株玉米青贮的pH和AN显著低于其他比例（P<0.05），AA显著高于其他比例（P<0.05）。3）瘤胃发酵参数方面：90%全株玉米+10%‘汾豆牧绿2号’处理下青贮在瘤胃发酵中AN、AA、丙酸以及体内干物质降解率最高；拉巴豆青贮的体内干物质降解率显著高于‘汾豆牧绿2号’（P<0.05）；100%豆科牧草的青贮在瘤胃发酵中pH最高，乙酸和体内干物质降解率最低。4）体外干物质降解率和产气量方面：从48 h开始，70%全株玉米+30%‘汾豆牧绿2号’青贮的体外干物质降解率一直显著高于其他处理（P<0.05）；‘汾豆牧绿2号’较拉巴豆的青贮在体外产气量更多；提高豆科牧草的混贮比例可显著降低青贮72 h的产气量（P<0.05）。综上，一定比例的混合青贮较全株玉米青贮更有利于提高青贮营养品质，改善青贮发酵品质，促进青贮的消化吸收，降低畜牧业的温室效应。70%全株玉米+30%‘汾豆牧绿2号’混贮模式为推荐混贮模式，为进一步在山西北部镰刀湾地区推广玉米-豆科牧草混贮技术及带状轮作技术提供数据支撑。

Effect of mixing ratio of legume forage and whole plant maize on feeding value of mixed silage

The purpose of this study was to explore the effects of different mixing ratios of legume forage and whole plant maize on the improvement of mixed silage feeding value. In this study， two legume grasses （''Fendoumulv 2'' and Dolichos lablab） were used as the main factors， and the mixing ratio of legume forage and whole plant maize as control group （90% whole plant maize +10% legume forage； 80% whole plant maize+20% leguminous forage； 70% whole plant maize +30% leguminous forage； 100% legume grass） as a secondary factor， 100% whole plant maize silage （CK），with a total of 9 mixed storage treatments and 3 replicates The nutritional quality， fermentation quality， rumen fermentation parameters， in vitro dry matter degradation rate and gas production of mixed silage were determined after fermentation. The results showed that： 1） In terms of nutritional quality， the dry matter of 100% ''Fendoumulv 2'' silage was the lowest in all treatments ， and the contents of acid detergent fiber， neutral detergent fiber and crude protein were the highest in all treatments. The crude fat of Dolichos lablab silage was significantly higher than that of ''Fendoumulv 2''（P<0.05）. The NDF， ADF and CP of 100% whole plant maize silage were the lowest in all treatments and its EE was the highest in all treatments. 2） In terms of fermentation quality， the pH and ammonia nitrogen of 100% ''Fendoumulv 2'' silage were significantly higher than those of other treatments（P<0.05）.The acetic acid of 100% Dolichos lablab silage was the lowest in all treatments. The pH and AN of 100% whole plant maize silage were significantly lower than those of other proportions（P<0.05）， and its AA was significantly higher than that of other treatments（P<0.05）. 3） In terms of rumen fermentation parameters， the AN， AA， propionic acid and dry matter degradation rate in body in rumen fermentation of 90% whole plant maize+10% ''Fendoumulv 2'' were the highest in all treatments. The dry matter degradation rate of Dolichos lablab mixed silage was significantly higher than that of ''Fendoumulv 2''. The pH of 100% leguminous forage mixed silage was the highest in all treatments in rumen fermentation（P<0.05）， and its acetic acid and dry matter the degradation rate in body were the lowest in all treatments. 4） In terms of dry matter degradation rate and gas production of vitro， since 48 h， the dry matter degradation rate in vitro of 70% whole plant maize +30% ''Fendoumulv 2'' mixed silage has been higher than that of other treatments（P<0.05）. The gas production in vitro of ''Fendoumulv 2'' mixed silage was higher than that of Dolichos lablab mixed silage. Increasing the mixing ratio of leguminous forage can significantly reduce the gas production at 72 h（P<0.05） . In conclusion， compared with whole plant maize silage， a certain proportion of mixed silage is more beneficial to improve the nutritional quality of mixed silage， improve the fermentation quality of mixed silage， promote the digestion and absorption of mixed silage， and reduce the greenhouse effect of animal husbandry. The mixing model of 70% whole plant maize +30% ''Fendoumulv 2'' is recommended， which can provide data support for the next step to promote the mixing technology and belt rotation technology of plant maize-legume forage in the sickle curvature area in northwest of Shanxi Province.