The effect of different additives on the fermentation quality, aerobic stability and in vitro digestibility of pea/wheat bi-crop silages containing contrasting pea to wheat ratios |
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| Authors: | A T Adesogan & M B Salawu |
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| Institution: | Institute of Rural Studies, University of Wales, Aberystwyth, UK |
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| Abstract: | Studies were conducted to compare the effects of using two microbial inoculants, a sulphite salt‐based additive, formic acid and quebracho tannins, on the fermentation quality, nutritive value and aerobic stability of pea/wheat bi‐crop silages. Spring peas (Pisum sativum var. Magnus) and spring wheat (Triticum aestivum var. Axona) were drilled together at rates that gave high (HP/W; 3:1) or low (LP/W; 1:3) pea to wheat ratios. The peas and wheat were harvested at the yellow wrinkled pods and late milk/early dough maturity stage, respectively, and conserved in 1·5‐kg polyethylene bag, laboratory silos. The bi‐crops were conserved without treatment (control) or treated with either of two lactic acid bacteria‐based inoculants Lactobacillus buchneri; applied at 105 colony‐forming units (CFU) g–1 fresh weight (FW) or Lactobacillus plantarum (applied at 106 CFU g–1 FW)], sulphite salts (applied at the rate of 1 ml sulphite solution kg–1 FW), quebracho tannins (applied at 16 g kg–1 FW) and formic acid (applied at 2·5 g kg–1 FW). Six replicates were made for each treatment, and the silos were opened after 112 days of ensilage. The level of peas in the bi‐crop influenced the effectiveness of the additives. With the exception of sulphite salts, all the additives significantly reduced the soluble nitrogen (N) and ammonia‐N concentrations of all the silages. The ratio of lactic acid to acetic acid was generally lower in the LP/W silages than in the HP/W silages, and the additive treatments only increased the in vitro digestible organic matter in dry matter of the LP/W silages. Of all the additives evaluated, formic acid resulted in the least aerobic spoilage in HP/W bi‐crop silages. However, in the LP/W bi‐crops, additive treatment was not necessary for ensuring aerobic stability. |
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| Keywords: | Lactobacillus buchneri Lactobacillus plantarum sulphite salts silage additives quebracho tannin |
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