Ev Thomas, agronomist with the Miner Institute, offers these comments on feeding new crop corn silage in a recent W.H. Miner Institute's Farm Report:
“You've heard this before: Don't be in a hurry to start feeding new crop corn silage. Of course, your alternatives are limited if your 2008 corn silage is about to run out. Purchasing corn silage from a neighboring farm may be a possibility, but with lousy milk prices you should be trying to avoid all unnecessary expenses. Perhaps a barter deal, trading old crop for new? During tough times it's important to be flexible.
“We've long known that corn silage that's been ensiled for several months is more digestible. Over a decade ago Brian Perkins used to harangue his Vermont/Northeastern N.Y. clients about not feeding new crop corn silage until "the holidays". (He meant Christmas, but some of the farmers chose to interpret this as Halloween.) Recent research has put some numbers to this recommendation: Protein and starch digestibility begin to increase several months after ensiling and continue to do so for many months thereafter. If you must start feeding new crop corn silage soon, have a digestibility analysis done on what you're now feeding and then on the new crop corn silage as soon as you start feeding it. That way you'll know how the new silage compares to what you have been feeding, and you and your dairy nutrition consultant can make the necessary ration adjustments using actual data instead of by-guess-and-by-gosh.
“In vitro analyses vary considerably between forage testing labs, so it's important to compare digestibility analyses from the same testing lab. It's more important to note the differences in NDF-d and DM digestibility between old and new crop corn silage than it is the numbers themselves. In other words, an NDF-d of 55 percent from testing lab "A" doesn't mean much unless it's compared to a second sample of corn silage analyzed by the same lab. Sending the second sample to testing lab "B", which reports that the NDF-d is 65 percent, doesn't necessarily mean that the second sample is more digestible.”
Source: W.H. Miner Institute