Don’t Harvest Corn Silage Too Soon

July 20, 2012 09:55 AM

In drought-plagued years like this, one of the biggest mistakes a dairy producer can make is to harvest corn silage too soon. Experts recommend waiting until plant moistures drop to 62% to 68%.

“It’s the most common mistake we see,” says Chris Wacek-Driver, Vita Plus Forage Program Manager. “We’ve seen some silages in Indiana coming in in the high 70s and low 80s.”

“Visual estimates of moistures are often inaccurate,” she says. As plant moisture drops, they should be checked frequently because moisture can drop one to three points per day or more. But you’ll need to monitor each field and each hybrid because each will dry down differently.

Even selecting plants at random, cutting them up, and testing moisture often won’t give an accurate estimate of plant moisture. “Once chopping moisture is close, run a field chopper through the field for a composite sample,” she says. But don’t feed this chopped material without testing for nitrates first.

If the plants are dead—no green in the lower leaves—wait until moistures drop to 62% to 68%, she says. Any wetter will result in poorer fermentation, high acid levels and the leaching of sugars from the silage mass in the bunkers.

If plants are still alive, they can respond to any rainfall that might occur and can add another ton of forage per acre. Even if the plant doesn’t add tonnage, Wacek-Driver recommends waiting five to seven days after a rain to harvest because nitrate levels will increase following a rain.

She also urges caution chopping and ensiling during warm weather of 85°F or higher. “Ensiling at these high temperatures can give you funky fermentation, especially if you’re filling large bunkers that take several days to fill and cover,” she says.

Value of drought-stressed silage

VitaPlus dairy specialists are urging producers to inventory their forage on hand and calculate how much they’ll need to get through this coming winter. Neighbors who grow corn for grain might be willing to sell their crop as silage, especially if it’s yielding little or no grain.

The crop can be priced several ways. If it has no grain, it can be priced on a relative feed value basis of local hay markets. You’ll need to adjust for dry matter and subtract harvesting cost to come up with a fair price for both buyer and seller, says Randy Greenfield,a  Vita Plus dairy specialist.

If the crop does have some grain in it, you can use University spreadsheets to determine estimated grain plus fodder value. At $8/bu corn, a rough estimate of the value of corn silage on as-fed basis from Purdue and the University of Wisconsin can be found below.

Corn bu/a                            30            50             75                 100

As fed tons/a                      7-8          9-11         12-13    &n​bsp;        14-16
Corn silage

Wisconsin                           $29    &nb​sp;     $40            $48                 $53

Purdue                                $28          $41            $50      ​           $56

For the complete drought management webinar from Vita Plus, click here.



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