不同收获期玉米青贮营养成分在奶牛瘤胃内降解率的研究

Study on the Rumen Degradabilities of Nutritional Composition of Corn Silage Harvested at Different Stages for Diary Cattle

本文旨在研究不同收获期玉米青贮对奶牛的营养价值。用3头装有永久性瘤胃瘘管的中国荷斯坦奶牛,采用3×3拉丁方设计对蜡熟期、乳熟期和乳熟前期的玉米青贮的主要营养成分进行了瘤胃降解率的研究。结果表明:(1)蜡熟期玉米青贮DM有效降解率(60.07%)分别比乳熟期(52.91%)和乳熟前期(45.13%)高7.16%(P<0.05)和14.94%(P<0.05);乳熟期比乳熟前期高7.78%(P<0.05)。(2)乳熟期玉米青贮NDF的有效降解率(30.77%)分别高于蜡熟期(28.59%)和乳熟前期(26.71%,P<0.05),蜡熟期和乳熟前期之间差异不显著。(3)蜡熟期ADF(25.73%)和乳熟前期玉米青贮(25.23%)没有明显差异,但都高于乳熟期(23.39%,P<0.05)。(4)蜡熟期玉米青贮CP有效降解率(81.93%)分别比乳熟期(76.43%)和乳熟前期(73.36%)高5.50%(P<0.05)和8.57%(P<0.05);乳熟期比乳熟前期高3.07%(P<0.05)。通过试验综合评价不同收获期玉米青贮对奶牛的营养价值是蜡熟期玉米青贮优于乳熟期,乳熟期玉米青贮优于乳熟前期。

The aim of the study was to determine nutritional value of corn silage harvested at different stages for dairy cattle. Three Holstein dairy cattles were fitted with cannulas in rumen,3× 3 Latin square experiment was designed to study the rumen degradabilities of major nutritional composition of corn silage harvested at premilk stage, milk stage and dough stage. The results show 1） the effective degradabilities （ED） of DM of the corn silage （60.07%） at dough stage was respectively 7. 16% （P〈0.05）and 14.94% （P〈0.05） higher than those of milk stage （52.91%） and premilk stage （45.13%）; the milk stage was 7.78% （P〈0.05） higher than premilk stage; 2）the ED of NDF of corn silage at milk stage （30.77%） was respectively higher than dough stage （28.59 %） and premilk stage （26.71%, P〈0.05）, however, there was not significant difference between dough stage and premilk stage; 3）the ED of （81.93%） CP of corn silage at dough stage was respectively 5. 50%（P〈0.05）higher than milk stage （76.43%）,and 8.57% （P〈0.05） higher than premilk stage（73.36%）. The milk stage was 3.07% （P〈0.05） higher than premilk stage. The experiment proved that nutritional value harvested at dough period for dairy cattle was better than harvested at milk. Nutritional value harvested at milk period for dairy cattle was better than harvested at premilk stage.