Applying the benzoate equivalent concept in rehydrated corn grain silage

Abstract

The benzoate equivalent (BEq) concept is a potential tool to compare silage additives that differ in active ingredients and their respective concentrations. Thus, our objective was to define BEq coefficients for potassium sorbate and sodium propionate in comparison to sodium benzoate, and establish an application rate based on the BEq to extend the aerobic stability of rehydrated corn grain silage. Dry corn kernels were ground (hammer mill, 8-mm screen), rehydrated to 350 g/kg moisture, and treated as follows: no additive (control), potassium sorbate (PS) at 125, 250, 500 and 1000 g/t, sodium benzoate (SB) at 250, 500, 1000 and 2000 g/t, sodium propionate (SP) at 500, 1000, 2000 and 4000 g/t, and a mixture of SB, PS and SP (BPS) at 250 + 150 + 53 g/t, 375 + 225 + 79 g/t, 500 + 300 + 105 g/t and 625 + 375 + 132 g/t, respectively. Treated grain was stored for 60 d in laboratory silos. All additives, alone or mixed, decreased the yeast and mold counts, ethanol and ethyl ester concentrations, and DM loss during fermentation, whereas more water-soluble carbohydrates were preserved in the treated silages. The untreated (control) corn grain silage rapidly deteriorated upon air exposure (∼ 41 h of aerobic stability), and PS, SB, and SP, alone or mixed, linearly improved the aerobic stability with increasing application rate. PS (BEq = 1.99) was more effective than SB (BEq = 1), and SB was more effective than SP (BEq = 0.35) in enhancing the aerobic stability. An application rate of approximately 1400 g/t of BEq could extend the aerobic stability of rehydrated corn grain silage for 3 d over that of untreated silage. In conclusion, the BEq concept is a plausible tool to compare commercial silage additive preparations and define their application rates in corn grain silage.