Submitted to: Forage Focus
Publication Type: Popular Publication
Publication Acceptance Date: 7/31/2023
Publication Date: N/A
Technical Abstract: The use of propionic acid-based preservative is common for dry hay to control heating, however its benefit is less understood in high-moisture baled silage. This project evaluated the use of four rates of acid preservative (0, 0.13, 0.44, and 0.80% of wet weight) and two forage moisture levels (Ideal = 52% or Dry = 44% moisture) in alfalfa-orchardgrass baled silage. No effects of acid application on baled silage nutritive value were noted, with small effects of moisture on fiber-bound protein concentrations and calculated energy values. Fermentation characteristics were more significantly affected by both acid application and bale moisture. Use of acid preservative caused a more restricted fermentation with numerically lower lactic acid and significantly lower total acid concentrations. An interesting result was linearly increased 2,3-butanediol concentrations with higher acid application rates, likely due to the restricted lactic acid bacteria fermentation. The ideal moisture bales had a more extensive fermentation (lower pH, higher acid%) than dry baled silage due to greater available moisture for bacterial activity. Heating patterns after opening of the baled silaged was not different for the moisture treatments, however use of acid preservative significantly reduced bale surface and core temperatures and accumulated heating degree days. The use of 0.44% acid preservative appears optimal to control bale heating after exposure to air, however cost and feeding system must be considered before deciding if this would be useful for your farming operation.