RATE AND EXTENT OF TOP SPOILAGE LOSSES IN HORIZONTAL SILOS

Alfalfa, corn, and forage sorghum silages were stored in farm- and pilot-scale silos, and DM and OM losses and fermentation characteristics were measured at three depths within the top meter of silage. The alfalfa was unsealed or sealed immediately with .15-mm plastic sheeting. Com and forage sorghum were unsealed, sealed immediately, sealed immediately after a topical application of a mold inhibitor, or unsealed for 7 d and then sealed after application of a mold inhibitor. All unsealed silage maintained higher temperatures within the top meter than sealed silage. Unsealed silage deteriorated completely at 25 and 0 to 33 cm in the farm- and pilot-scale silos, respectively, and farm-scale silage stored at 50 cm lost more DM and OM in unsealed than in sealed silos. Unsealed silage began to deteriorate immediately above 33 cm, and deterioration progressed to 67 cm in the silage from all three crops. Immediate sealing preserved more DM and OM after d 180 at 25 cm than delayed sealing. Recoveries of OM estimated by an equation containing silage ash content were highly correlated with actual OM recoveries in all unsealed silage. Estimated and actual recoveries were not highly correlated in sealed silage, particularly below 33 cm.