Aerobic stability of maize silage stored under plastic films with different oxygen permeability

BACKGROUND. The most important factor that can influence silage quality is the degree of anaerobiosis maintained during conservation. The quality of the plastic film is a key factor, since the permeability of polyethylene to oxygen is too high for silage conservation. The aim of this work was to assess the effects of the interaction between three plastic films with different degrees of oxygen permeability and different maize silage conservation times on fermentation, microbial quality and aerobic stability. RESULTS. The conservation time affected the pH, lactic and acetic acids, 1,2-propanediol and lactic to acetic acid ratio, and showed higher pH, lower lactic acid concentration and lactic to acetic acid ratio but higher acetic acid and 1,2-propanediol concentrations in silages conserved for 110 d versus silages conserved for 55 d. The plastic film affected the pH, lactic and acetic acids and lactic to acetic ratio. The yeast count was lower and aerobic stability was higher for silage conserved under the oxygen barrier film for both conservation periods. CONCLUSION. The positive interaction between length of storage and the increased anaerobiosis of silage during conservation provided by the oxygen barrier compared to polyethylene film helped reduce the yeast count and increase the aerobic stability of maize silage, even when less acetic acid was produced during ensiling.