【作者】 崔利宏；

【导师】 吐日根白乙拉；

【作者基本信息】 内蒙古农业大学 ， 动物营养与饲料科学， 2008， 硕士

【摘要】 本试验选用3只体况良好、体重32kg、年龄1.5～2岁的安装有永久性瘤胃瘘管内蒙古半细毛羯羊,采用自身对照试验设计和瘤胃尼龙袋法,比较研究了不同精粗比日粮(Ⅰ:2:8、Ⅱ:3:7、Ⅲ:4:6)条件下绵羊瘤胃发酵特性和不同收割期(8月4日、8月27日、9月15日)锡林郭勒盟灰腾希勒草场混合牧草营养物质降解率。结果表明,饲喂Ⅰ、Ⅱ和Ⅲ3种精粗比例日粮绵羊瘤胃发酵特性如下:日平均瘤胃pH值分别是6.35、6.38和6.28(p>0.05),pH值变化幅度在6.07～6.55之间;瘤胃纤毛虫数组间差异不显著(p>0.05);瘤胃氨态氮(NH3-N)日平均值(mg/100ml)分别是7.12、10.70和10.20,变化范围在5.44～14.72(mg/100ml),日粮Ⅰ的平均瘤胃NH3-N浓度极显著低于日粮Ⅱ和日粮Ⅲ(p<0.01);瘤胃菌体蛋白(BCP)浓度,日粮Ⅱ和日粮Ⅲ极显著高于日粮Ⅰ(p<0.01);TVFA浓度组间无明显变化(p>0.05)。3种不同收割期牧草常规营养成分相近。同一种精粗比日粮不同收割期牧草在同一个尼龙袋取样时间点(0h、2h、6h、12h、24h、36h、48h、72h)DM、NDF、ADF、CP的降解率差异均不显著(p>0.05),牧草收割期越晚,降解率越低;不同精粗比日粮条件下同种牧草DM、NDF、ADF、CP降解率差异也不显著(p>0.05),但日粮Ⅱ和日粮Ⅲ的比日粮Ⅰ略高。由上述结果可知,2007年锡林郭勒灰腾希勒草场的牧草8月前已成熟,之后一个半月时间内牧草营养物质含量变化甚小,营养物质在瘤胃内的降解率也基本没有变化。从牧草营养价值考虑收割时间应该在8月之前。更多还原

【Abstract】 Three healthy Inner Mongolia semi-fine wool wethers (1.5-2 years old, BW 32 kg) fitted with the ruminal permanent fistula were used by a self-control test design to investigate the change of the degradability rule of forage nutrients by rumen nylon bag method in sheep fed three diets of different concentrate-to-forage ratio (dietⅠ, 2:8; dietⅡ, 3:7; dietⅢ, 4:6) and forages at different harvesting periods (Aug 4th,Aug 27th,Sept 15th). Ruminal environmental fermentation parameters and degradability of nutrients were determined during the treatment period.The results showed: Daily average ruminal pH value of sheep fed three diets of different concentrate-to-forage ratio was 6.35, 6.38 and 6.28(p>0.05), respectively; Ruminal pH value was between 6.07 and 6.55 for one day. The amount of rumen ciliate was no difference with three diets (p>0.05). Daily average NH3-N concentrations (mg/100mL) were 7.12, 10.70 and 10.20, and the range of NH3-N concentrations was 5.44-14.72 mg/100mL, NH3-N concentrations of dietⅠwere very significantly lower than dietⅡand dietⅢ(p<0.01). Ruminal bacterial protein concentrations of dietⅡand dietⅢwere very significantly higher than dietⅠ(p<0.01), but there was no difference between dietⅡand dietⅢ. The total VFA concentration was no change (p<0.05). Nutrients of forage at three different harvesting periods were the same. The degradability of DM, NDF, ADF, CP at the same sampling time(0h, 2h, 6h, 12h, 24h, 36h, 48h, 72h) in forages at three different harvesting periods in the same dietary concentrate-to-forage ratio were no significant different (p>0.05), but the degradability of them was lower with increasing harvesting periods. The degradability of DM、NDF、ADF、CP in the same forage at the different dietary concentrate-to-forage ratio was no significant different too(p>0.05), but dietⅡand dietⅢslightly higher than dietⅠ.The results also showed that forages have already been matured before August 2007 on the Huitengxile grassland in Xilinguole, Inner Mongolia. The contents of nutrients of forage after August and their degradability did not change. Forages should harvest before August considering their nutritive value.更多还原