Evaluation of associate effects of ruminants forages in the Qinghai Plateauusing in vitro gas production technique

The in vitro gas production technique was used to evaluate associate effects of mixed with two ruminants forages of silage cornstraw, alfalfa green hay and oat green hay with 0∶100, 25∶75, 50∶50, 75∶25 and 100∶0 in the Qinghai plateau. This study showed that 48 h gas production and theoretical maximum gas production were positively related to the content of NDS/CP(P＜0.001), OM(P＜0.01), NDS(P＜0.05), and negatively related to the content of ADF(P＜0.001), NDF(P＜0.05), CP(P＜0.05). Gas producing velocity were positively related to the content of OM(P＜0.001), NDS(P＜0.001), NDS/CP(P＜0.01), and negatively related to the content of ADF(P＜0.001), NDF(P＜0.001). The lag times of gas production were positively related to the content of ADF(P＜0.01), NDF(P＜0.05), and negatively related to the content of OM(P＜0.01), NDS(P＜0.05), NDS/CP(P＜0.05), and these results showed the fermentation level of combined forages in vitro gas production were mainly affected by the proportion of nonstructural carbohydrates and crude protein. When the forages are mixed, combination proportion of silage cornstraw and alfalfa hay by 25∶75, silage cornstraw and oats by 50∶50, alfalfa green hay and oat green hay by 50∶50 were relatively appropriate, and with the increase of fermentation time, associate effects quantity of each combinations showed a gradually decreasing trends.