Effects of microbial inoculant and moisture content on preservation and quality of round baled alfalfa

Abstract

The effects of microbial inoculant and moisture content of alfalfa, stored as large round bales, on preservation and quality were examined in a 3-yr study. Alfalfa was round baled at 18, 45 and 60% moisture with 45 and 60% moisture bales stored in 23-m-long plastic tubes. At each moisture level, half the bales were treated with a microbial inoculant (Lactobacillus plantarum) during baling. All bales were weighed and sampled prior to storage (into storage) and prior to feeding (out of storage) with a core sampler. Field recovery and crude protein content of forage at 18% moisture were significantly lower than for forage at 45 and 60% moisture levels. ADF contents were decreased (P < 0.01) by moisture content in year 1, while the NDF contents were affected similarly in all the 3 yr. Storage recoveries were not affected by either moisture content or inoculant. Nutritive value of forages was evaluated, using completely randomized designs, in feeding trials with 96 steers and digestibility trials with 36 wethers. Dry matter intake by steers and nutrient digestibility in sheep were not affected (P < 0.05) by either moisture level or inoculant treatment. Feed conversion efficiencies and average daily gain of steers receiving 45 and 60% moisture forage were higher than for those fed 18% moisture forage. Results from this study indicated that harvesting alfalfa at 45 and 60% moisture as silage produced a better-quality product for steers than at 18% moisture dry hay and that treatment with microbial inoculant was not beneficial in preserving high moisture forage. Key words: Alfalfa, large round bales, inoculant, silage, steer, sheep, digestibility, hay