EFFECTIVENESS OF PROPIONIC ACID FOR PRESERVING ALFALFA HAY IN LARGE ROUND BALES

Abstract

A propionic acid-based commercial mold inhibitor for high moisture hay was compared with an equivalent and a 10-fold higher concentration of propionic acid for preserving alfalfa hay in large round bales. When packaged, the percent moisture content (MC) of each of the five treatments was: CC1 (Control) 26.1, CT1 (commercial formulation equivalent to 0.03% propionic acid) 25.0, LPA1 (0.03% proprionic acid) 31.1, PA1 (0.3% propionic acid) 23.6 and PA0 (0.3% propionic acid) 17.8. There were no significant (P > 0.05) differences in MC among CC1, CT1 and PA1 treatments. The application of the commercial mold inhibitor (CT1 treatment) proved ineffective. This treatment, as compared to CC1 treatment, showed no significant (P > 0.05) effects on dry matter (DM) loss, cumulative degree-days (above 6 reference points from 35 to 65 °C), chemical composition, voluntary intake and digestibility of nutrients. Hay from PA1 treatment was significantly (P < 0.05) lower in neutral detergent fiber (NDF) and significantly (P < 0.05) higher in energy digestibility than that from the CC1 and CT1 treatments. Although the maximal temperature was higher for PA0 hay than for PA1 hay, the PA0 hay cooled down sooner. The PA0 treatment was lowest (P < 0.05) in the cumulative degree-days above 35 °C, crude protein (CP), NDF, cellulose, NDF-N and acid detergent insoluble N; and highest (P < 0.05) in hot-water-insoluble N, digestibilities of DM, CP and energy. Because of very high initial MC, the LPA1 hay deteriorated very markedly and its DM loss was about twice of that for CCI hay. Key words: Propionic acid, alfalfa hay, digestibility, temperature of hay, large round bales