Assessment of ensilability and chemical composition of canola and alfalfa forages with or without microbial inoculation

Canola (Brassica napus L) and alfalfa (Medicago sativa) can produce nutritious silage. An experiment was conducted to evaluate the effects of microbial inoculation on fermentation products and silage quality of canola and alfalfa. The trial was conducted in 2011 in Matamoros, Coahuila, Mexico. Silages were made in mini-silos with a density of 736 kg/m³ of fresh forage. A 2x2 factorial arrangement of treatments in a completely randomized design with four replications per treatment was used. Interaction between forage crop and microbial inoculation for fermentative characteristics were observed, whereas for chemical composition only main effects were significant. Microbial inoculation did not affect canola silage fermentation products. Microbial inoculation improved alfalfa silage quality by decreasing pH and increasing concentrations of lactic acid, as well as energy content. Crude protein (CP), neutral detergent fiber (NDF), and net energy of lactation (NE_L) content in canola silage were 259 g/kg DM, 234 g/kg DM, and 6.2 MJ/kg DM, respectively. As compared to alfalfa silage, canola silage had slightly lower concentrations of fiber, CP (4.8%), and energy (0.9–5.3%). The results indicated that the ensiling process of canola forage produced a well-preserved material however nutrient content and fermentation products were lower than in alfalfa silage.