To say that this fall's corn silage harvest will be challenging is an understatement. A summer of cloudy, rainy weather has put most corn planted at normal times in the Northeast several weeks behind on maturity, according to crop-watching agronomists and dairy nutritionists. Late-planted silage corn may be harvested in November or later – if Mother Nature holds off her killing frost.

Don't rush silage harvest!
That's the one piece of advice unanimously offered. If you have to deal with immature corn, leave the crop to mature as long as possible to increase dry matter yield per acre, explains Heather Darby, University of Vermont Extension agronomist. "That's your key to achieving milk production."

Today's elite silage hybrids, when properly managed, have the opportunity to capture greater energy yield per acre at later maturity than we traditionally have recommended in the past, adds Bill Mahanna, Pioneer Hi-bred dairy nutritionist. "With good processing of the crop, corn silage harvest dry matter can be extended up to 38 to 40% to capture this extra energy value."

Newer hybrids have more late season agronomic health bred into them for laying down more starch for kernel development and yet maintaining digestible neutral detergent fiber right up until the kernels undergo the black-layering.

There's a 'watch-out' for a grower or chopping crew where harvest may take several days: Harvest should commence at an earlier maturity with the intention that the last corn will be captured in the 38 to 40% DM area, he adds.

Immature corn will most likely be harvested near 34 to 35% DM. It should be stored in bags, bunkers and piles – separate from better quality silage.

After a killing frost ...
After a frost, closely monitor how fast the crop is drying down. Then chop as fast as possible with the goal in mind of staying in the 32 to 35% DM range, adds Bill Seglar, senior dairy nutritionist for Pioneer.

Frost halts kernel development, resulting in lowered starch concentrations and silage tonnage yields. Forage analysis of frosted crops is essential, he stresses. Many times, higher sugar levels in the stalk – not translocated into the ear – will offset low starch, resulting in a corn silage that may have energy values similar to that of normal corn silage.

Nitrate levels should be monitored when harvesting and when feeding stressed and/or frosted corn silage, notes Seglar.

For more silage tips, catch Vicky Carson's "Milk It" column in your soon-to-arrive September issue of American Agriculturist. For more on managing immature and frosted corn silage, visit this Web address: pss.uvm.edu/vtcrops. In the left column, click on "Corn silage and grain". Then scroll down to "Managing immature and frosted corn silage."