Re-ensiling and its effects on chemical composition, in vitro digestibility, and quality of corn silage after different lengths of exposure to air

The exposure of silages to air during storage and during transfer between silos may lead to the growth of aerobic microorganisms and so compromise the chemical composition, silage quality, and in vitro digestibility. In this study, we simulated the transfer and re-ensiling of silages to check for possible effects of exposure to air in relation to chemical composition, in vitro digestibility of dry matter, and silage quality and aerobic stability. Twenty silos were made, and after 150 d, 15 of them were opened and re-ensiled after 12, 24, and 48 h of exposure to air. During the aerobic exposure period, temperature varied from 9.1 to 28.9 °C (mean: 18.5 °C). Among the parameters evaluated, we observed variation only in lignin content; however, this variable did not affect the in vitro digestibility of the silage. A linear increase of pH values as increasing air exposure time (P < 0.05) also was observed. However, these changes did not have practical importance due to the small observed variation. The pH values of the experimental samples were lower than 4.2, which is indicative of well-preserved corn silages. Therefore, the chemical composition, the quality, and the aerobic stability of silage were not influenced by different periods of air exposure.