A trouble-shooter for common silage problems
By Dr. Jim White

Beef and dairy producers know problems can occur in almost every silage program. Read up on these common problems.

Excessive effluent (seepage or run-off) Causes

• Ensiling forages too wet (low dry matter [DM] content) for the silo type and size.

• Weather did not allow the forage to be field-wilted properly before chopping.

• Forage was not “conditioned” when it was cut.

• Forage was placed in a window that was too bulky for the time allowed for field-wilting.

• Whole-plant corn, sorghum or cereals were harvested at an immature stage of growth.

• Some aggressive enzyme additives increase run-off and have caused silage to fall and ooze out of bunkers.

Solutions

• Follow more narrow weather forecasts to plan forage management decisions.

• Take advantage of new mowing, cutting and conditioning equipment technologies.

• Coordinate the merging of windows/swathes with the time of chopping.

• Monitor the maturing/drying process of each field of corn, sorghum or cereals so harvesting time can be scheduled properly.

Caution: Effluent has a very high biological oxygen demand. It should be contained near the silo of origin and not allowed to enter a nearby pond or water course.

Large variations in the ensiled forage’s dry matter content and nutritional quality.

Solutions

• Use multiple silos and smaller silos, which improve forage inventory control.

• Ensile only one cutting and/or variety of “hay crop” forage per silo.

• Minimize the number of corn and/or sorghum hybrids or cereal varieties per silo.

• Shorten the filling-time, but do not compromise packing density.

Missing the optimum time to make corn, sorghum or cereal silages.

Causes

• Warm, dry weather can speed the maturing process of the plant’s grain and forage components.

• Wet weather can keep harvesting equipment out of the field.

• Difficulty arises in scheduling the silage contractor.

Solutions

• Plant multiple corn or sorghum hybrids or cereal varieties with different season lengths.

• Improve communication between the beef or dairy producer, crop grower and silage contractor.

High concentrations of butyric acid and ammonia-nitrogen, particularly in hay-crop silages.

Note: These two components indicate that a forage underwent a clostridial fermentation.

Solutions

• Chop and ensile all forages at the correct DM content for the silo type and size.

• Properly pack to exclude as much oxygen as possible, which will minimize the loss of plant sugars during the aerobic phase.

• Apply a homolactic bacterial inoculant to all forages to ensure an conversion of plant sugars to lactic acid.

• Avoid soil contamination throughout all mowing/ conditioning, harvesting and silo-filling operations.

• Note that wilting legume crops that are rained on are at greater risk of clostridia growth, the soiling has increased, and the plant matter has lost soluble carbohydrate. If it is not possible to control percent DM by wilting, adding sugar (corn syrup) solids is helpful.

High concentrations of acetic acid, particularly in wetter corn, sorghum and cereal silages.

Note: Indicates the forage underwent a prolonged, heterolactic fermentation. The silage will have a distinct “vinegar” smell. It is common to see a 1- to 2-foot layer of bright yellow, sour smelling silage on the floor of bunker, trench or drive-over pile silos with wet corn silage.

Solutions

• Ensile all forages at the correct DM content.

• Use a homolactic inoculant to ensure an efficient conversion of crop sugars to lactic acid.

Heat-damaged silage.

Note: This silage will be dark brown and have a strong burnt caramel/tobacco smell. This is a common problem with drier legume silages.

Causes

• Temperature of silage exceeds 130 degrees.

• High feed temperatures will cause protein to be “bound.” Protein reacts with a carbohydrate and acts more like fiber-lignin than protein.

• Palatability will be good, but protein value is reduced.

• Most heat in silage is from respiration. Respiration will continue as long as oxygen is available. Being able to quickly achieve anaerobic conditions will limit heat damaged silage.

• High silage density coupled with rapid and thorough sealing of the silo will restrict heating to a minimum.

• In well managed silages, silage temperature does not increase more than 10 degrees over the ambient temperature.

Solutions

• Harvest at correct stage of maturity (not too mature!).

• Ensile forages at the correct DM content (not too dry!).

• Do not chop forage at too long a particle size.

• Fill silos in a timely manner.

• Achieve a uniform distribution of forage and a high packing density (a minimum of 15 pounds of DM per cubic foot).

Aerobically deteriorating silage during the feedout phase.

This is seldom a problem with legume silages.

Causes

• Yeast growth occurs on silage. Yeast will not grow in the absence of air, but it needs little air (0.5 percent) to grow.

• Bacillus may be involved, especially if the silage feels slimy.

• Poorly packed, drier cereal grain silages with high porosity tend to be at the greatest risk.

Solutions

• Harvest at correct stage of maturity, (not too mature!).

• Ensile forages at correct DM content, (not too dry!).

• Do not chop forage at too long a particle size.

• Achieve a high packing density.

• Fill rapidly—fungal counts tend to increase with delayed filling and sealing.

• Maintain a uniform and rapid progression through the silage during the feedout phase.

• Avoid feeding from large silos during warm weather.

• Do not leave silage-based rations in feed bunks for an extended period of time, particularly in warm weather.

• Slow the onset of aerobic deterioration by the application of an anti-mycotic at ensiling.

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

Solutions

• Achieve a high packing density in the forage within the top 3 feet of the silage surface.

• Seal the silo immediately after filling is completed.

• Apply buffered propionic acid to the surface prior to sealing.

• Apply sufficient, uniform weighting material to the polyethylene sheet.

- Overlap the sheets by a minimum of 4 to 6 feet.

- Consider whole truck tires that touch to weight the overlap.

- Whole tires are preferred over tire walls, and truck tire walls are preferred over car tire walls.

• Prevent damage to the seal during the entire storage period.

Excessive mold in bagged silage.

Causes

• Fungi present plus adequate moisture, air and time to grow.

• Air-tight seal not established. In a silage which has 0 percent oxygen, the environment at 21 percent oxygen has a partial pressure gradient that tries to push oxygen into the silage.

• Erratic filling giving a rough bag, which allows air to channel through the silage.

• Bags overstretched—film failure.

• Inadequate removal rate. Should be at least a foot a day in warm weather.

• Lack of low porosity silage—as density increases, porosity decreases. Bag density is greater at the bottom of the bag than at the top of the bag. Erratic filling may give rise to horizons where air was not expressed and fungal growth was greater. Commonly will see mold pockets or balls not observed until 3 weeks or so after opening the bag.

• Most commonly seen molds in the Midwest in bagged silage are mucor, monelia and penicillium.

Solutions

• Ensure adequate equipment maintenance and that equipment is operated by competent personnel.

• Avoid erratic filling rates.

• Do not overstretch bags.

• Ensure adequate removal rates.

• Apply an anti-mycotic at ensiling. The salts of some organic acids are compatible with LAB inoculants.