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0806 PD: Higher cutting improves silage

J.W. Schroeder Published on 07 August 2006

University of Delaware researchers found increasing the cutting height of silage corn from 5 inches to just under 19 inches improved its nutritive value, but it reduced silage yield about 10 percent.

Three leafy silage hybrids were cut at both stubble heights at black layer and half milk-line stages. The higher-cut silage was higher in dry matter and starch than the lower-cut corn, but crude protein and acid detergent fiber (ADF) were lower. Neutral detergent fiber (NDF) and lactic acid also tended to be lower.

When fed to dairy cows, the higher-cut silage showed tendencies for greater NDF digestion, higher milk production and improved feed efficiency.

Troubleshooting common silage problems
Keith Bolson, professor emeritus at Kansas State University, covers some of the problems encountered when ensiling forages.

•High acetic acid concentrations, particularly in corn and sorghum silages that were too wet at harvest
Indicates forage underwent prolonged, heterolactic fermentation. Silage will smell vinegary. Seeing a 1- to 2-foot layer of bright yellow, sour-smelling silage on bunker floors, trenches or drive-over piles is common.

Solutions:
–Ensile all forages at correct dry matter (DM).
– Use a homolactic inoculant to ensure efficient conversion of drop sugars to lactic acid.

•Heat-damaged silage
This type of silage will be dark brown and have a strong burned-caramel or tobacco smell. Signals significant reduction in digestibility of “bound” (Maillard chemical reaction) protein and energy.

Causes:
–Ensiled forage temperature increases more than 10º to 12ºF above ambient at harvest, or exceeds 115º to 120ºF during the first two weeks in the silo.
–Presence of oxygen allows continued plant and microbial respiration, which creates heat.

Solutions:
–Harvest at correct maturity.
–Ensile at correct forage DM.
–Chop hay crop forages no longer than 1 inch and whole plant corn or sorghum to 0.25 to 0.5 inch for ideal composition.
–Fill silo uniformly and quickly.
–Achieve minimum packing density of 15 pounds of dry matter (DM) per cubic foot.

• Deteriorating corn silage during feedout

Solutions:
–Harvest at correct maturity.
–Ensile at correct forage DM.
–Do not chop longer than 0.75 inch if the crop is processed, or to 0.5 inch if not run through a kernel processor.
–Achieve minimum packing density of 15 pounds of DM per cubic foot.
–Uniformly and rapidly progress through the silage during feedout.
–Avoid feeding from large silos during warm weather.
–Do not leave silage-based rations in feedbunks for extended periods of time, particularly in warm weather.

• Excessive “surface spoilage” in sealed bunker, trench and drive-over pile silos

Solutions:
–Densely pack forage within the top 3 feet of the silage surface.
–Slope surface to drain water off bunker or pile.
–Seal silo immediately after filling.
–Apply sufficient, uniform weighting material to plastic sheet.
–Overlap sheets by a minimum of 4 to 6 feet.
–Use whole truck tires, which touch each other, to weigh down portions of plastic overlap.
–Whole tires are preferred over tire walls, and truck tire walls are preferred over car tire walls.
– Prevent damage to plastic sheet.

Dairy producers can save forage and money if they implement and share these solutions with the entire silage team.  PD

—From North Dakota State University, Dairy Connections, Vol. 15, No. 3

J.W. Schroeder, Extension Dairy Specialist, South Dakota State University

See more articles like this at www.progressivedairy.com

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