Topics : Hay & Silage : Hay & Silage Preservation : Large Round Bale Silage
Large Round Bale Silage
Steps in Making Large Round Bale Silage
Mowing with a mower-conditioner is best. Leave the mowed forage in the swath long enough for it to wilt to 55-65 percent moisture. Drying periods usually range from two to three hours, or overnight if mowing is done late in the day.
Baling with a fixed-chamber baler is easiest since it makes uniform size bales which fit easily into bags or stack neatly when wrapped. Some balers will require modifications, such as scrapers to prevent gum buildup on belt rollers, or shields to prevent wrapping of the crop. A slow forward speed helps make tight bales which are less likely to spoil. Net tying or plastic twine are recommended; sisal twine should be avoided since the chemical twine preservatives often degrade the plastic wrapping. Inoculants can be added, but usually are not necessary. Hauling the bales to a bagging or wrapping site immediately helps insure feed quality as well as bale roundness, which is mainly important when wrapping.
Wrapping bales is quicker than bagging, but it requires a bale wrapping machine, which means a capital expenditure which you don't have with bagging. Wrapping machines cost around $6000 to $12,000 depending upon the level of sophistication desired. In order to justify the machine cost, one should wrap a minimum of 100 bales per year. A recent study revealed that two workers can wrap 25 - 30 bales per hour.
Plastic for wrapping usually is one mil (0.001 inch) thick and comes in rolls which are 5000 or 6000 feet in length. Each roll will cover 25-30 bales. The plastic costs $3 to $4 per bale and can be used one time only. Each bale requires from 1.5 to 2 pounds of plastic, so ask your supplier about a recycling or rebate option for the used plastic.
Quality plastic has a tackiness agent which is crucial to proper sealing. The plastic is typically stretched 50 to 55 percent in order to get the correct tension. Several years ago, instructions were to wrap each bale rotation with a 25 percent overlap of the plastic, therefore providing each bale with four layers of plastic. Today, four layers are still recommended, but in order to create a better seal, the bale should be wrapped with a 50 percent overlap and then wrapped twice. Like bagging, the wrap is NOT airtight but it does restrict enough air exchange that fermentation can take place. Best results are achieved when 100 percent virgin plastic is used, which is warranted for a minimum of one year.
Bagging is trickier than wrapping. After a few bales are made, check the bag fit. Bag at the storage site only, since this area already should be cleared of obstacles and nuisances that puncture the bags. Once the bag is over the bale, push out excess air before sealing. To seal the bag, a strong hand is needed to twist and stretch the bag end while a second hand or a second person ties a knot with rope. Twist tightly and tie once, then bend the twisted plastic back onto itself and tie the two twists together. Polyethylene (PE) plastic film used for these bags is not airtight. As a matter of fact, low density PE is four times more permeable to carbon dioxide gas than it is to oxygen gas, allowing the bags to vent excess carbon dioxide gas as fermentation begins.
If you find holes in the bagged bales, patch them as soon as possible, since wind causes loose plastic to bellow out providing an air exchange which usually spoils most of the outer layer of the bale. Duct tape and masking tape last about three weeks before they fall off, but bag suppliers have a PE tape which adheres for bag life. Bags are rarely reusable because of minor pinholes.
No research has revealed that any bag color is better than another as far as silage quality is concerned. Black plastic bags have an ultraviolet inhibitor called carbon black, which limits bag degradation under sunlight. White and green bags will degrade quicker. If a bag is made from quality materials, your supplier should be willing to guarantee it for one year.
Bags cost from $6 to $8 each in 1991 prices. For comparison, it would cost about $52 and $30 per ton to ensile similar amounts of forage to 150 and 300 bales, respectively, in long tube type bags. The cost to ensile the equivalent of 300 bales in a concrete stave silo is over $42 per ton if the silo is filled only once and $21 per ton if the silo is filled twice each year.