Effect of ensiling field bean, field pea and common vetch in different proportions with whole-crop wheat using formic acid or an inoculant on fermentation characteristics

Whole-crop field bean (FB), field pea (FP) and common vetch (CV) [155, 213 and 238 g dry matter (DM) kg(-1)] were ensiled in 1.5 L laboratory silos with whole-crop wheat as mixtures of 0, 0.25, 0.50, 0.75 and 1.00 of fresh weight (FW). Silages were ensiled (i) without additive, and (ii) with formic acid (FA) (4 L t(-1)) or (iii) an inoculant (Lactobacillus plantarum, 10(6) colony-forming units g(-1) FW) as additives. The concentrations of water-soluble carbohydrates in herbage of whole-crop FB, FP, CV and wheat were 93, 157, 67 and 114 g kg(-1) DM and the buffering capacities were 588, 710, 755 and 429 mEq kg(-1) DM respectively. Field bean and FP silages were mainly well preserved with low pH values and moderate fermentation losses, except for FB-only silage without additive which had a high butyric acid concentration. Common vetch silages had higher pH values and were less well fermented compared to the silages of the other legumes. For all legumes, FA reduced ammonia-N concentrations more effectively compared to other additive treatments. In conclusion, in FB and FP silages the use of FA or an inoculant, as additives, ensured good preservation up to a proportion of legume in the herbage of 0.75. With all legume silages, and with those containing CV, only FA, as an additive, adequately restricted protein breakdown.