Tips for successful bale wrapping and making high quality baleage
Making dry hay in the Midwest can be very challenging, but especially so with the first cutting. In Minnesota, it is possible to have some amount of rain one day in three during May and June. Also, soil moisture and humidity levels are not conducive to drying. Because of this, many have chosen to chop some or all of their hay crop. Are there other options? For many, wrapping high moisture baled hay has become a viable option.
Baleage vs. wrapping
Although often used interchangeably, making quality baleage vs. simply wrapping large bales are not necessarily the same thing. Making baleage implies fermentation as in haylage; so think of an ideal moisture content of 50 to 65 percent.
Wrapping bales may be a storage substitution for a building or additional storage options. This may be done at as low as 15 to 30 percent moisture. Any kind of forage that can be baled can be wrapped.
Consistent moisture content is key
One key to making baleage or wrapping bales is consistent moisture content through the windrow so it is consistent in the bale. Research by Kilcer in New York (see graph below) showed a greater use of wide swath mowing helps in not only the speed of drying of the hay, but also in the uniformity of moisture content within the windrow.
The sooner we can drop the moisture content of the plant material below 65 percent, the sooner plant respiration stops. Plant respiration uses plant sugars for energy, which decreases the nutritive value of the forage and can cost up to $30 to $40 per ton of forage. Also, those sugars are valuable for faster fermentation, whether making haylage or baleage. Faster drying also decreases the interval from cutting to harvest and decreases the risk of rain exposure. The goal, if possible, is to have the swath width at least 80 percent of the cutter bar width.
The second step is to make a dense bale. Air provides oxygen to continue respiration. Trapped air in a bale can also lead to excessive heating and possible mold growth. There are molds of different types on all hay that is harvested, but in small numbers. Much like haylage in a bag or pile, moisture greater than 50 percent allows for better packing. The same is true in the baling process. Net wrapping creates a more uniform outer surface prior to wrapping.
Keep in mind when making large round or large square bales for wrapping that baling at the higher moisture content greatly increases the weight of the bale. As a rule of thumb, 50 percent moisture in the bale doubles the weight of the bale. Many of these large round bales can weigh up to a ton or more. Make sure you have the right equipment to handle the increased weight, adequate hydraulics, counter balanced loaders and good tires.
The last important step in making quality baleage is using enough wraps of plastic to ensure complete oxygen exclusion. Undersander and co-workers at the University of Wisconsin did some of the early work with wrapping almost 20 years ago. What they found was that it takes a minimum of 6 mils of a high quality plastic to accomplish this.
As the chart shows, it takes a minimum of 6 mils to rapidly drop the internal temperatures in a wrapped bale. These bales were wrapped at 30 percent moisture, which would make them more susceptible to inadequate wrapping. I would not suggest using heavier plastic than 1.5 mil or fewer than 4 wraps; there is a minimum number of wraps needed to overlap seams to seal out air. Use good quality plastic that has UV resistance. Exposing wrapped bales to the weather and sun for more than two years greatly increases the risk of plastic breakdown.
For much of the same reasons as mentioned before, it is imperative to wrap the bales as soon as possible after baling. The shorter the exposure time to air, the sooner anaerobic fermentation starts, which will lessen the loss of dry matter in the form of plant sugars. It will also lessen trapped air in the outer layer and subsequent surface mold growth.
Most forages that can be baled can also be wrapped. If you bale in the 50 to 65 percent moisture range, you are more likely to get better fermentation. At less than 50 percent moisture, and as moisture decreases, extra plastic layers may be beneficial to exclude air.
Drier bales do not make as dense a bale, they may have drier stems that could puncture the plastic, and they may not ferment as fast or as much as a wetter bale. However, wrapping dry bales at 25 to 45 percent moisture can still allow for adequate preservation, give you more storage options, increase the nutritive value over dry hay, and be a lower cost alternative to other storage methods.