Propionic Acid as Hay Preservative1
- W. R. Knapp,
- D. A. Holt and
- V. L. Lechtenberg2
In search of a method to prevent quality deterioration in hay stored before it is adequately cured, propionic acid was added to hay at baling time. Its effectiveness as a preservative was evaluated. Alfalfa (Medicago sativa L.) hay was baled at 32.4% moisture. Immediately after baling, propionic acid was applied to the bales at rates of 0.02, 0.2, 0.5, and 1.0% of the weight of the hay. The hay was then covered with polyethylene for 48 hours. Temperatures were recorded for 3 weeks following treatment. Samples were taken at baling and after 2 months in storage.
All of the untreated hay became moldy, heated to ≥ 55 C, and showed significant losses in dry matter, carbohydrates, in vitro dry matter disappearance, and in vitro cell wall disappearance during storage. Total N, ammonium N, and acid detergent fiber N concentrations increased in control and treated hay during storage.
Hay treated with < 1% propionic acid underwent storage changes similar to those occurring in untreated hay and was not effectively preserved. The 1% acid rate inhibited molding and heating and reduced dry matter loss during storage from 15.1 to 7.6%. Decrease in in vitro dry matter and cell wall disappearance during storage was least with 1% acid treatment. Acid treatment reduced loss of in vitro cell wall disappearance. These results indicate that propionic acid may have value for preserving incompletely cured hay if it is applied at rates of ≥ 1%.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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