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Let quality and safety determine proper bunker and pile size

Chris Hallada Published on 07 August 2009

As herd sizes have grown, so have the storage units that preserve the forages used to feed dairy cows.

Still visible over the landscape where dairy has persisted for decades, upright silos often stand empty as monuments to an era when they reigned supreme.

Replacing them are bunker silos and feed pads storing large quantities of silage. The speed forages need to be harvested and fed, the greater ease of unloading silage trucks and wagons and ultimately the sheer numbers of mouths needing to be fed efficiently have prompted these changes.

Both harvesting and feeding flows, as well as feeding efficiency, have improved with increased use of bunkers and piles. However, it is tempting to improperly size these units for various reasons.

Many articles have been written on management concerns that need to be addressed, such as proper filling techniques, packing, covering, etc. to obtain optimal forage quality results.

Ultimately, one of the biggest issues requiring consideration is proper sizing of the storage unit. The most economical size is seldom the largest structure.

This is particularly apparent when accounting for the impact forage quality has on milk production and animal health. Beyond economic considerations looms a larger issue. Oversized bunkers and piles are potential death traps! More discussion about that later.

Improperly sized bunkers or piles are nearly impossible to manage for optimal forage quality and can seriously challenge farm profitability.

Storing silage in front of, on the side of or on top of existing feed or structures does not allow for ideal forage management. Delayed fill (defined as more than three to four days) represents a major obstacle to efficient fermentation.

Oxygen needs to be depleted to begin effective acid production and preserve the forage. Oxygen depletion cannot happen until effective sealing occurs.

Once opened, large forage faces challenge minimum feedout recommendations. Often, in order to deliver quality forage to the feedbunk and prevent spoilage, piles are split and some forage is sacrificed.

Put simply, there is a large amount of forage energy, protein and spoilage loss that occurs when storage units are sized improperly.

Properly sizing the forage structure allows for:

1. Better segregation of forage quality to match specific animal requirements
Better fermentation
More economical forage production (i.e., higher energy, more protein preserved and less spoilage, translating into more milk per ton of forage)
Better equipment “flow” from field, resulting in more optimal filling, packing and sealing
Feedout that matches storage unit size

More troubling than any of the above arguments are the safety concerns mammoth bunkers and piles pose to employees and service personnel working with the dairy’s forage and nutrition program. Improperly sized bunkers or drive-over piles have the potential to cause serious injury and even death.

When asked at a recent series of meetings, most feed consultants working with large forage bunkers or drive-over piles have either seen a cave-in or the after-effects of such a collapse. Piles taller than equipment can create dangerous overhangs.

Numerous farm stories related by farm employees tell of cracked cab windows due to tumbling silage from an overhang or of enough silage collapsing that a person or a piece of equipment would have become quickly engulfed and potentially suffocated or seriously injured if in its path.

Another story recalls a family hearing an entire bunker wall collapse as they sat on their deck enjoying the evening sunset. (The collapse was caused by silage piled in excess of bunker walls not built to sustain the extra silage weight).

Those are the lucky ones who received warning signals. Not so lucky are the people like the Pennsylvania farm worker who died of suffocation after a silage pile collapsed on him.

Two bystanders could not dig quickly enough to save him. Or consider the situation in Minnesota, where a farm consultant was killed because a frozen chunk of silage fell from the top of a large bunker face.

These people paid the ultimate price. Left behind are family and friends who must deal with the emotional pain, suffering and loss of a loved one.

The impact of a farm accident reaches beyond emotional consequences. It can place immediate financial stress on a farm operation.

Depending on the size and focus of the operation, a serious injury or death can eliminate an owner, manager or employee for a short time or even permanently. The financial stress can be the result of excessive medical expenses, operational inefficiencies or loss of income.

The financial impact to the farm is hard to predict and may vary based on the corporate structure of the operation, who was injured, how seriously and insurance coverage.

Insurance claims often center around coverage options, such as worker’s compensation, long-term disability and general liability.

If the injured person is a non-employee of the operation, the farm may still be held liable for costs associated with the injury through what is known as premises liability. Plus, if negligence of the property owner is suggested, civil liability may exist.

With most farms being family-owned and operated, the injured person potentially could be an immediate family member. This aspect, coupled with the financial stresses and costs, can add additional strain to an operation recovering from a farm accident.

It is far better to have a plan and guidelines in place to recognize and prevent potential accidents, than to deal with the above consequences.

The following are some commonsense guidelines when working with large bunkers or drive-over piles.

1. If you don’t have a reason to be at the face of a bunker or pile – don’t be there! Even well-maintained faces have the potential to collapse. If a forage sample is required, determine if there is another way to potentially take that sample without putting yourself or another person at risk. Can the silage mechanically be moved away from the silage face? Can the feeder mix a sample up in the mixer wagon?

Make sure another person is aware you are in the forage storage area. If the bunker or pile exceeds 12 to 15 feet in height, it is recommended to have another person with you but stationed away from the silage face.

2. Make sure all equipment operators know you are in the silage area, particularly during harvest season. If a farm employee is charged with pulling samples at harvest, brightly colored clothing can help identify them visually.

3. Never approach a pile with a silage overhang or where tires or other weighted material is overhanging or visibly close to a silage edge. Frozen silage is particularly hazardous.

4. Be careful if you are on the top of a pile. This includes initial covering of the pile, removal of tires, pitching spoiled silage or inspecting plastic for holes.

5. It also includes employees on pack tractors. Equipment roll-overs are the leading cause of farm-related deaths.

Huge, towering piles of forage are often the result of an expansion. With so many other aspects of the operation requiring decisions, the forage storage area can be forgotten. Often it is expanded “in place” or hemmed in by buildings.

The space above a plot of land is often considered “free” versus valuable land used for crop production. Like many major decisions, short-term views can pose significant risks to the long-term financial health and viability of the farm operation.

Even for those farm entities that can financially survive, an accident that results in serious injury or death can call into question the desire of key owners or employees to continue the business.

The following are some guidelines to help keep your storage units safe.

1. Do not pile feed higher than your feedout equipment can safely reach. Undercutting forage creates dangerous overhangs, can loosen silage from the top and allows weighted material (like tires) to fall or begin the process of a silage collapse.

2. Post signs limiting access only to authorized personnel.

3. Do not pile feed higher than the walls. Piling feed higher stresses the structural integrity, potentially cracking walls and ultimately leading to wall collapse.

4. Visually inspect walls for cracks and structural defects. Promptly repair any damages.

5. Limit spoilage on the top of the pile. Less spoilage means less pitching of feed off the top, negating having to put someone at risk.

6. Don’t underestimate the amount of space needed to maneuver harvesting and packing equipment. Too little space can create bottlenecks and potential for accidents and can result in improper pile/bunker filling. It is a good idea to get your custom operator or equipment operators involved when planning a potential bunker/pile or evaluating a current site.

7. Make sure pack tractors have roll-over protection, seat belts and intact cabs.

Bunkers and piles have the potential to be efficient, economical ways to store feed. Proper sizing for forage quality and evaluation of animal needs will improve farm profitability. More important, though, is that a well-thought-out forage storage significantly reduces the risk of human injury and even death.  FG

Chris Hallada
Forage Program Manager
Vita Plus Corp