Ensiling sugar beets: Effect of mixer feed used for co-ensiling on fermentation products and losses when ensiled in vacuum bags

Co-ensiling beets with other feeds allows for year-round feeding of beets and reduces the risk of dry matter (DM) loss as effluent from the silage. This study aimed to evaluate the effect of co-ensiling high DM beets with maize and grass/clover silage, grass seed straw, fresh beet pulp, and high DM concentrates (dried beet pulp, wheat distillers’ grain solubles; DDGS, wheat bran, rapeseed meal, sunflower meal, soybean hulls, and maize gluten feed) on gaseous weight loss (GWL), loss of effluents, and silage quality. Beets from harvest year 2021 were used to produce two sets of silages in laboratory silos, resulting in a total of 2 pure beet silages and 12 mixed beets silages. GWL was measured by weighing the laboratory silos until 181 days of ensiling. Fermentation was terminated by freezing after 30, 92, and 181 days of ensiling where loss of effluent was also measured. Total GWL was highest in the two pure beet silages (mean ± SEM; 282 ± 5.47 and 250 ± 7.94 g/kg DM, respectively), and differed among the mixed silages depending on mixer feed. Effluent was only observed in the pure beet silage in Set 1. Silage DM content at 181 days of ensiling was lowest for the two pure beet silages (180 ± 10.9 and 165 ± 5.95 g/kg). For all silages, pH was below 4.25 by 30 days of ensiling. Ethanol concentrations at 181 days of ensiling were highest in the two pure beet silages (345 ± 11.5 and 287 ± 11.8 g/kg DM). L-lactate content of pure beet silages was 38.4 ± 1.85 and 31.1 ± 1.21 g/kg DM at 181 days of ensiling. In Set 1, L-lactate content was lower in beets ensiled with maize silage, grass seed straw, dried beet pulp, or DDGS compared to pure beet silage. In Set 2, L-lactate content was higher in beets ensiled with maize gluten feed compared to pure beet silage. Silage concentration of NH₃ varied depending on mixer feed. The NH₃ content at 181 days of ensiling was 0.817 ± 0.626 and 2.05 ± 0.601 g/kg DM for pure beet silages and was highest in beets ensiled with grass/clover silage in both silage sets (16.4 ± 0.63 and 17.6 ± 0.60 g/kg DM). Co-ensiling beets with forages, high DM concentrates, and protein-rich feeds included in this study lowered fermentation weight loss, eliminated the loss of effluent, and resulted in silages of good fermentation quality.