MADISON -  Slow to fill, slow to empty are two misconceptions surrounding tower silos that the International Silo Association (ISA) would like to dispel.

ISA officials took issue with a dairy modernization guide that reported “Upright silos… have limited value on large dairies because of the time required to fill and unload them.”

That's simply not true officials at the International Silo Association told those gathering at recent annual meeting.

Modern silo unloaders with feeding rates exceeding 800 pounds per minute have been reported in major agricultural papers across the country.

"These speeds are due to advances in unloading using center discharge unloaders.  Individual farmers using this technology consistently report feeding times faster than those achieved when using horizontal storage methods," the ISA stated. "With the advent of “Feed Automation”,  the use of a fast unloading tower silo is critical to the process."

In response to the slow filling rates, ISA says, the filling rates on tower silos exceed the rates possible using methods that require manual packing. ISA has reports of producers and custom harvesters across the country filling towers at speeds exceeding 100 tons per hour, and several who are filling at speeds over 120 tons per hour. These numbers have also been reported in major agricultural papers throughout the country.

According to ISA, it is a common perception that large amounts of feed cannot be stored in a tower silo. However, towers have been built up to 30 feet in diameter and over 130 feet tall. 

"A unit of this size will hold nearly 3000 tons of corn silage or 1050 tons of dry matter.  That is enough forage to meet the forage needs of more than 200 milking cows for a year," according to the ISA report.

Another perception that concerns ISA is the predominate school of thought in the area of dry matter losses in forage, also known as feed shrink.

"There has been a lot of talk about dry matter loss and the great costs associated with it.  While most people understand that tower silos are very effective in reducing dry matter losses, the tower silo has not often been seen as a solution to this problem," ISA officials pointed out. 

With the backing of multiple university based studies, ISA reports that when comparing the average dry matter losses in a tower silo with that of a bunker or pile, there is an average dry matter savings of 9%.  Multiple producers who have moved from horizontal storage to towers have reported to ISA that they have seen acreage savings as high as 23% after the first year of use. 

ISA also refutes the idea that it is expensive to unload from the tower silos. Citing an implement costs study put out by the University of Minnesota, they claim that there are actually significant savings in using an unloader to extract feed as opposed to a tractor, skid steer, or front-end loader.

"You can run a 7.5 horsepower motor on an unloader for one hour for much less than running a tractor for one hour not to mention the time and labor savings," ISA stated.  "While unloaders may be more expensive today, the price overall is comparable and many times cheaper than the devices used to unload forage in horizontal storage."

For more information, email or call 610-607-3622.  

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