Effects of UV radiation on the process of wilting and application of additives at ensiling on the fermentation quality of Siberian wildrye silage on the Qinghai-Tibetan plateau

Effects of lactic acid bacteria (LAB) and formic acid (FA) on silage quality of ultraviolet (UV)-radiated Siberian wildrye (Elymus sibiricus L.) were studied on the Qinghai-Tibetan plateau. Siberian wildrye seeds were sown in early April, 2012 and harvested in 2013, 2014 and 2016. Fresh forage was radiated for 0, 4 and 8h under ambient/laboratory UV radiation conditions during the wilting process, and then mixed with LAB inoculant (10(5)cfug(-1) fresh matter [FM]) and FA (3mLkg(-1) FM), respectively, no additives treatment as control. After additive treatments, chopped Siberian wildrye plants were packed in 30cmx40cm polythene bags and stored in a dark room at ambient temperature (<15 degrees C) for 90days. Silages of UV-radiated Siberian wildrye had higher (P<0.05) pH and ammonia-nitrogen (N) content, lower (P<0.05) acetic and propionic acid content and invitro ruminal dry matter digestibility. Compared with control, treatments with additives (especially for inoculant LAB) enhanced pH decline, increased (P>0.05) acetic acid content, decreased (P<0.05) butyric acid and ammonia-N content of silages of UV-radiated Siberian wildrye. It was concluded that the application of FA and inoculant LAB at ensiling could reduce the negative effects of extended UV radiation on the process of wilting.