本试验旨在研究构树不同部位（构树叶、构树枝叶、构树枝）与奶牛常用粗饲料（苜蓿干草、燕麦草）的瘤胃降解特性。选用3只装有永久性瘤胃瘘管的中国荷斯坦奶牛，采用尼龙袋法测定5种饲料的干物质（DM）、粗蛋白质（CP）、中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）瘤胃降解规律。结果表明：1）构树叶的CP含量显著高于苜蓿干草（P<0.05），NDF含量显著低于苜蓿干草（P<0.05）；构树枝叶的CP含量与苜蓿干草差异不显著（P>0.05），NDF含量显著低于苜蓿干草（P<0.05）；构树枝的CP含量与燕麦草差异不显著（P>0.05），NDF含量显著高于燕麦草（P<0.05）。2）5种饲料的DM有效降解率差异显著（P<0.05），由高到低依次为构树叶、构树枝叶、苜蓿干草、燕麦草和构树枝。5种饲料的CP有效降解率差异显著（P<0.05），由高到低依次为苜蓿干草、构树叶、构树枝叶、燕麦草和构树枝。构树叶的NDF有效降解率最高，显著高于其他4种饲料（P<0.05），其中构树枝叶与燕麦草差异不显著（P>0.05）。5种饲料的ADF有效降解率差异显著（P<0.05），由高到低依次为构树叶、燕麦草、苜蓿干草、构树枝叶和构树枝。综上所述，构树不同部位具有作为奶牛非常规饲料资源的潜力。

The aim of this study was to evaluate the rumen degradation characteristics of different parts of paper mulberry (paper mulberry leaves, paper mulberry twigs and leaves and paper mulberry twigs) and commonly used roughage (alfalfa hay and oat hay) for dairy cows. Three Chinese Holstein cows with permanent ruminal cannulas were used to evaluate the ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) by nylon-bag technique. The results showed as follows:1) the CP content in paper mulberry leaves was significantly higher than that in alfalfa hay (P<0.05), while the NDF content was significantly lower than that in alfalfa hay (P<0.05). There was no significant difference in CP content between paper mulberry twigs and leaves and alfalfa hay (P>0.05), while the NDF content in paper mulberry twigs and leaves was significantly lower than that in alfalfa hay (P<0.05). There was no significant difference in CP content between paper mulberry twigs and oat hay (P>0.05), while the NDF content in paper mulberry twigs was significantly higher than that in oat hay (P<0.05). 2) There was significant difference in the DM effective degradability among five kinds of feedstuffs (P<0.05), and from high to low were paper mulberry leaves, paper mulberry twigs and leaves, alfalfa hay, oat hay and paper mulberry twigs. There was significant difference in the CP effective degradability among five kinds of feedstuffs (P<0.05), and from high to low were alfalfa hay, paper mulberry leaves, paper mulberry twigs and leaves, oat hay and paper mulberry twigs. The NDF effective degradability of paper mulberry leaves was the highest, and significantly higher than that of other four feedstuffs (P<0.05), but there was no significant difference in NDF effective degradability between paper mulberry twigs and leaves and oat hay (P>0.05). There was significant difference in the ADF effective degradability among five kinds of feedstuffs (P<0.05), and from high to low were paper mulberry leaves, oat hay, alfalfa hay, paper mulberry twigs and leaves and paper mulberry twigs. In conclusion, different parts of paper mulberry have potential value for unconventional feed resources in dairy cows.