It's worth repeating: air is the enemy of high-quality silage. As silage is opened and fed, it is once again exposed to air, and oxygen allows aerobic organisms that survived the ensiling process — such as bacilli, yeasts and molds — to grow.
These microbes use sugars, lactic acid and other nutrients for growth and produce carbon dioxide and heat as byproducts. Excessive heat accumulation can denature proteins and other nutrients in the silage. Molds growing on the silage may also produce mycotoxins that can reduce animal performance and cause herd health and fertility issues.
Heating and spoilage during feedout is one of the greatest contributors to DM and nutrient losses in silage production. To minimize these losses, be sure to use good face management by maintaining a straight feedout face with shavers. Avoid removing silage too far ahead of feeding, do not leave silage sitting around in loose piles and feed out at a rate fast enough to avoid heating.
Research-proven inoculants can help reduce the growth of spoilage yeasts and molds. Inoculants containing Lactobacillus buchneri 40788 applied at a minimum of 400,000 CFU per gram of silage or 600,000 CFU per gram of high-moisture corn (HMC), have been reviewed by the FDA and allowed to claim improved aerobic stability.
When changing over to feeding the new season silage, remember that it is different feed compared to what the cows have currently been getting. Make the changeover gradually. Substituting 25 percent of the "old" silage with new each week — i.e. week, 1 to 25 percent; week 2, 50 percent; week 3, 75 percent; week 4, 100 percent — should minimize the chance of digestive upsets. But also keep in mind that the digestibility of the starch in corn silage can increase over eight to 10 months of storage. This should be checked on a monthly basis so that rations can be adjusted if necessary.