Livestock producers who are considering wrapping bales have a number of questions to ponder. The first: Why think about wrapping bales at all?
For haylage production, if there are no silos available, wrapping bales is a less expensive alternative for making a 15 to 20 percent protein forage feed. “If you are wrapping dry hay, it will improve the forage’s digestibility,” says Marvin Hall, professor of forage management at Penn State University.
However, there is a caveat. Once the alfalfa or grass is cut, wrapping bales won’t improve the quality of the forage that the animals eventually eat, Hall says. “This is definitely a case of garbage in, garbage out. If forage quality is poor to start with, wrapping it in plastic will not improve its quality.”
Still, the cost of single-bale wrappers and inline systems (bale wrappers that wrap forage in a single long wrap) will save the cost of silo construction. Of course, this has to be balanced against the risk of not having a solid structure to protect the integrity of the fermentation process.
With either wrapping system, forages are encased in heavy plastic instead of cement-stave or metal structures. This means any punctures, whether caused by handling or wildlife, will reduce the efficiency of the fermentation process that produces quality feed.
There are steps farmers can take to reduce this risk. Recent research suggests that farmers should wrap bales with light-colored plastic rather than darker colors.
“Farmers who use darker plastic will see it break down more quickly than those who use lighter-colored material. The darker plastic breaks down faster in the summer heat and sun, making it more permeable to oxygen and limiting the fermentation process,” Hall explains.
How well the bale is wrapped will make a difference. Hall has seen research suggesting that the best seal is achieved with six wraps per bale.
The best candidates for wrapped haylage are first and fall cuttings. When making plastic-wrapped haylage, the win-or-die breaking point on preserving forage quality is a producer’s willingness and ability to wrap bales the same day hay is harvested.
Carbohydrates in forages increase from the moment of cutting throughout the day and peak at sunset. “Baling one day and wrapping it the next leads to a loss of carbohydrates, which are needed to feed the bacteria that bring about fermentation,” says Hall.
In the first phase of fermentation, oxygen feeds both mold growth and the acetic acid-producing bacteria. That’s why wrapping immediately after harvest is a good idea. The plant cells are producing heat, which is an ideal situation for molds to start growing.
If wrapped quickly, that heat burns up the oxygen, which clears the way for the lactobacillus bacteria in the forage to begin the fermentation process. The faster that occurs, the faster the lactobacillus bacteria can get down to the important job of creating lactic acid during what is called the anaerobic stage.
If all is working as it should be, the pH and the temperature of the silage drop in this phase. “In properly fermented silage, more than 70 percent of the acids will be lactic acid,” notes Hall.
Fermentation takes from 9 to 15 percent of the forage’s dry matter, which translates into protein loss. That’s why it’s important that what is wrapped is of the highest quality.
Hall says, “If protein is at 12 percent when harvested, whatever comes out of the wrap will be less than 12 percent.”
Forage scientists discovered that there are two kinds of lactobacillus bacteria present during fermentation. They are called homofermenters and heterofermenters.
Homofermenters convert one molecule of glucose (plant sugar) into two molecules of lactic acid. “Lactic acid lowers the pH of forages and begins the fermenting process,” says Hall.
Heterofermenters convert one molecule of glucose into one molecule of lactic acid and some carbon dioxide. “So when it comes to fermenting, the homofermenters are much more efficient,” he adds.
There are a number of silage additives called homofermenter inoculants on the market. Research at the University of Wisconsin-Madison has shown that these products, though not 100 percent effective, tend to work better on haylage than corn silage.
What do they deliver? They cut dry matter loss with varying degrees of effectiveness, depending on the product used. Whether that means higher rates of gain or milk production is a question that can only be answered with further study.
As part of a 2010 study, Gordon Groover, associate professor and extension economist at Virginia Tech, estimated wrapping costs. Those costs are offset by huge reductions of harvest and storage losses.
For example, it can be a real feed saver when alfalfa is harvested during or immediately prior to rain. Tedding alfalfa leads to leaf shatter, and leaf shatter means protein loss.
“Harvest losses in dry hay can range from 15 percent to 45 percent,” says Groover.
He thinks bale wrapping makes more sense for the milking string than for brood cows.
“Wouldn’t you be better off grazing or reducing stocking rates rather than making an investment like this?” he asks. “Do you really need that kind of quality forage for them?”
High-quality feed is more important to growing stock, like feeder cattle, making the investment a more worthy consideration. “That is a completely different question than maintenance,” Groover emphasizes.
Farmers who are increasing herd size and need a constant rate of gain or milk production might look at bale wrapping as a consistent source of quality feed. “Investing in bale wrapping is not a lot more expensive than building a shed for dry hay storage,” Groover says.
On the flip side, once the weather gets cold, grazing options for farms in the Northeast blow away with the onset of snow. Wrapped bales mean plenty of forage available for feeding over the winter.
The investment also makes sense when taking hay from rented land where there is no storage available. “Bales left on the ground lose quality over time, but wrapping bales preserves their quality longer,” Groover says.
Feeding the beasts
Groover says it’s also important to consider whether the farm’s existing equipment can handle the necessary power and accessory requirements, or if it will be necessary to invest in additional equipment. He says, “Farmers with fewer resources might think about using custom operators to get the job done.”
Small tractors may not have the necessary muscle. “Single-bale wrapping requires an 80 hp tractor to efficiently and safely move the wet bales, and possibly a second 55 to 60 hp tractor to use as a power unit,” he says.
Many inline wrappers come equipped with their own power units, eliminating the need for a second tractor.
Moving bales also requires tong-style bale grabbers. “You can’t use a bale spear on sealed bales,” Groover points out.
There are some hidden charges as well, since producers must also consider how they will deal with postharvest storage. If there is no structural storage available, gravel pads may be necessary to get the wrapped bales off the ground.
Single-bale wrappers cost less than inline systems, but they require more wrapping time and plastic film per bale. Some of the inline systems require end caps or plastic hay bags to seal the ends of the lines.
Wrapping bales can be an economical answer when quality counts, when haying on rented properties, and when silos are not available. Just be sure to include all of the factors when pushing that pencil.