基于主成分分析的精料、构树和全株玉米青贮的组合效应评价

本试验旨在利用主成分分析评价精料、构树和全株玉米青贮以不同比例组合后的组合效应，筛选最佳组合比例。试验设计3个精粗比(40∶60，50∶50，60∶40)，15种日粮组合比例，利用体外模拟瘤胃发酵测定15个组合的瘤胃发酵指标，通过主成分分析法对其进行综合评价。精粗比40∶60时，40∶60∶0和40∶45∶15组的氨态氮(NH₃-N)含量较高；精粗比50∶50时，50∶0∶50，50∶12.5∶37.5和50∶25∶25组的72 h产气量(GP₇₂)较高(P>0.05)，50∶25∶25组的NH₃-N含量最高；精粗比60∶40时，60∶10∶30组的乙酸(AA)、丙酸(PA)和总挥发性脂肪酸(TVFA)浓度显著高于其他各组(P<0.05)。精料∶构树∶全株玉米青贮比例为60∶10∶30，综合主成分值最大。在本试验条件下，日粮中添加构树可以改善肉牛体外瘤胃发酵性能，当精料∶构树∶全株玉米青贮比例为60∶10∶30时，组合效果最佳。

Evaluation of the Associative Effects of Concentrate、Broussonetia papyrifera and Whole Plant Corn Silage based on Principal Component Analysis

The objective of this experiment was to evaluate the associative effects of different feed combinations based on principal component analysis. The experiment set 3 concentrate to forage ratios (40:60,50:50 and 60:40) and a total of 15 feed combinations with concentrate,Broussonetia papyrifera and whole plant corn silage. Rumen fermentation characteristics were measured using in vitro gas production method and comprehensively evaluated by principal component analysis. The NH₃-N in 40:60:0 and 40:45:15 groups were higher (P>0.05) when the ratio of concentrate to forage was 40:60. When the ratio of concentrate to forage was 50:50,the GP₇₂ in the groups 50:0:50,50:12.5:37.5 and 50:25:25 were higher (P>0.05),and the NH₃-N in 50:25:25 group was the highest. When the ratio of concentrate to forage was 60:40,the concentrations of acetic acid,propionic acid and TVFA in the 60:10:30 group were significantly higher than the other groups (P<0.05). The comprehensive combination effect value is the largest when the concentrate:Broussonetia papyrifera:whole plant corn silage was 60:10:30. In conclusion,the supplemental of Broussonetia papyrifera can improve the in vitro rumen fermentation characteristics of cattles. It was the best combination effect when the concentrate:Broussonetia papyrifera:whole plant corn silage was 60:10:30 based on principal component analysis.