While the spring forages have already been ensiled, alfalfa, corn, sorghum, and high moisture corn will be headed to the silage pits soon at many feedyards and cattle operations. Dr. Keith Bolsen, Professor Emeritus, Kansas State University, has been working with silage for 50 years and shares some important reminders about how to have a safe and efficient silage program in 2020.

The way we put up silage has really changed in the last several years, according to Dr. Bolsen. There are crop growers and multiple contractors who are responsible for the chopping, hauling, packing, and sealing, and each plays a specialized role, especially in the High Plains. Dr. Bolsen refers to the feedyard and this group of specialists as the “silage pentagon,” a team of players all working together to put up the best possible silage. It is essential that each specialist knows the feedyard’s expectations, gets their job done in an acceptable and timely manner, and follows safety guidelines.

Safety First

“There is a lot of extra vehicle traffic and people at most feedyards during these two- to three week harvest windows. Truckers are delivering forage, someone is taking a forage sample, tractor operators are packing, a covering contractor’s crew is sealing the silage surface, and it can all be happening at the same time,” Bolsen said. Sending these employees home safe at the end of the day should be the number one goal in every silage program.

Feedyards and chopping, packing, and covering contractors should all schedule a mandatory meeting to discuss safety guidelines and expectations for the silage harvest with their employees. Everyone whose ‘feet touch the ground’ in the field or near the bunker silo, silage pile, scales, or any machinery or equipment must wear a high visibility safety vest.

Silage Priorities – A High Density, An Effective Seal & Apply an Inoculant

These three practices are crucial in a well-managed silage program, and achieving a high density leads the way. Why? Silage density and ‘shrink loss,’ measured as tons of dry matter (DM) ensiled versus tons of DM actually fed are inversely related. Because today’s high capacity forage harvesters get the crop out of the field faster, Dr. Bolsen contends, “we have not kept up” with packing density. Often there are not enough tractors or enough tractor weight to properly pack every load to the desired density, which is typically 15 to 17 lbs. of DM per cubic foot. There must be good communication throughout the day among the feedyard, the chopping contractor, and the packing contractor. The crop delivery rate in tons per hour to the bunker or pile should be measured in real time throughout the day, and the packing contractor should be prepared to add another tractor. If we reach the silage density target, the reduced ‘shrink loss’ justifies an
extra tractor, according to Bolsen.

A few guidelines and management practices that can increase density include:

• Only an experienced employee should operate a pack tractor.
• The arrival of trucks and forage to the bunker or pile should be evenly spaced during the day.
• The forage packing ‘ramp’ in bunkers and piles should not exceed a 1 to 3 slope (i.e., 1 foot of vertical for each 3 feet of horizontal).
• Forage should be spread in uniform layers of 4 to 6 inches, and packing must be continuous throughout the entire filling process.
• Increase the number of pack tractor passes over each forage layer. Caution: This usually requires an additional pack tractor.
• A pack tractor’s outside tires should be adjacent to the tire track of the previous tractor pass.
• When possible, drive up and back down the forage ramp. Avoid making 180 degrees turns on the ramp or fl oor of a bunker or front apron of a pile.
• When two or more pack tractors are used, establish a packing procedure to increase the efficiency of the tractors and avoid collisions.
• Packing for a longer time at the end of the day is of little value because it does not remove air trapped in the forage that is more than 1.5 to 2 feet below the surface.

Dr. Bolsen believes effective sealing of bunkers and piles is the second most important practice in a feedyard’s silage program today. Scheduling the covering contractor is critical. Any delay in sealing increases the shrink loss and the amount of visible surface-spoilage in the outer one to three feet of silage.

Bolsen referenced a Cal Poly study that looked at shrink loss in relation to when corn silage piles were sealed. A 24-hour delay in sealing a produced a 25 percent greater shrink loss in the outer 1.5 feet after 90 days compared to a pile that was sealed immediately after packing. “Every 24 hours you delay and leave the surface uncovered, you’re experiencing substantial loss,” he says.

Bolsen also recommends that a true oxygen barrier (OB) film be used under the sheet of standard white on black plastic. “We need a higher use rate of OB film in the silage industry. It’s a “game changer” and dramatically reduces the shrink loss in the outer one to three feet of a bunker or pile. Losses can be cut by 50% or more.”

A few guidelines and management practices that help minimize surface spoiled silage include:

• The forage surface should be sealed as soon as possible after filling is completed. Note: Fill bunkers and piles from back to front, which allows sealing to occur every 1 or 2 days.
• The OB film and plastic sheet should overlap on the forage surface by a minimum of 3 feet and should reach about 4 feet off the silage surface around the perimeter of piles.
• The OB film and plastic sheet should be placed so runoff water cannot come in contact with the silage.
• Uniform weight should be placed on the sealing material(s) over the entire surface of a bunker or pile, and the weight placed on the overlaps should be doubled or tripled.
{ Bias-ply truck sidewalls are the most common alternative to full-casing tires.
{ Gravel bags are an effective way to anchor the overlaps, and gravel bags provide a heavy, uniform weight at the interface of the sealing material(s) and bunker silo walls.
• Regular inspection and repair of the sealing material(s) is recommended, because if air and water penetrate the silage mass, surface spoilage can develop quickly.
• Use caution when removing the sealing material(s) near the edge of the feed-out face. Note: When working on the top of an overfilled bunker silo or silage pile, wear a safety harness tethered with a heavy rope or cable for fall protection.

Today, applying an effective lactic acid bacterial inoculant at the forage harvester is recognized as an important practice in every well-managed silage program. Why? Inoculants promote a rapid and efficient conversion of fermentable carbohydrates to lactic acid, which improves both preservation efficiency (i.e., reduced shrink loss) and utilization efficiency (i.e., better feed conversion). Inoculants that contain Lactobacillus buchneri also extend the ‘bunklife’ during feed-out, which is important for corn silage fed in the warm weather months or when face management is less than ideal.

Final Thoughts

Bolsen says there is a positive relationship between silage safety and shrink loss. “Almost everything we do to make a silage program safer also makes it more efficient. If I add an extra pack tractor, I reach a higher density and the silage will take up less space (volume). This will lower the feed-out face, and the bunker or pile will be safer.”

A successful silage program at a feedyard takes planning, preparation, and commitment. It’s also not a perfect world and details can and do ‘fall through the cracks.’ This can happen at any time from the first load of forage delivered to the bunker or pile to the last. Equipment breakdowns, weather delays, moving forage harvesters to a new location, a shorthanded crew … these things happen. Good communication between the feedyard and the other four points of the pentagon can help minimize the disruption and its effect on the silage program.


Feed-Lot magazine was saddened to hear that Dr. Bolsen passed away just days after collaborating with us on this article. For more information on Dr. Bolsen, his life and his commitment to silage safety, please visit his Silage Safety Foundation website.

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