by Tamara Scully
Making quality forage means growing a quality crop, harvesting the crop at its optimal level of energy, minimizing the loss of that energy, preventing spoilage, and reducing feeding loss. While the process involves a lot of variables, getting it done right is worth it. High quality hay, haylage or baleage not only provides better nutrition, it saves money. Getting the most from your forages requires attention to detail, and proper selection, care and handling, from seed to feed.
“Forages are the basis of the dairy and the beef industry,” Dr. Daniel Undersander, University of Wisconsin Forage Agronomist, said. “You cannot make up for low quality forage.”
Variable Costs and Quality
Seed is a variable cost, as are fertilizer and harvesting costs. Overall, the variable costs don’t really change much from year to year. But yield per acre, and forage quality, will increase due to good seed, fertilization and harvesting practices. Incurring a bit more of an expense each season is worth the price, as the enhanced quality of the forage will result in a higher return per acre, and reduced feeding cost.
Properly selecting high-quality seed, no matter what forages you grow, will go a long way on maximizing the return on your investment. Cheaper seed results in yield loss, even when everything else is done correctly. Producers should use the right amount of fertilizers to optimize yield, and not skimp to save money.
We should all get whatever we can from manure,” Undersander said, while fertilizing properly to maintain yield and quality.
While a high yield might mean a few more trips to the barn, in general the equipment still has to do the same thing, no matter how much is harvested. Harvesting twice as much forage from an acre increases energy use about 15 percent, he said.
“Harvesting costs don’t really change that much with yield,” Undersander said.
Harvesting, capturing and maintaining forage quality is particularly important to the dairy industry. Low quality forage means less milk production. No matter how much grain is fed, low quality forage will always decrease milk output.
Research data from trials with alfalfa, cut at four different stages of growth – and therefore quality – and fed to milking cows given four different levels of grain supplementation, illustrated this concept.
“Every quality of forage, when we fed more grain, we did increase the milk output a little bit,” Undersander said, although no amount of grain supplementation could compensate for poor forage quality. “We need quality forage for dairy cattle.”
Alfalfa should be cut prior to flowering. In the dairy feeding trials, alfalfa cut at bud stage led to the highest levels of milk production. When cut at early bloom, no amount of grain supplementation could make up for the loss of milk production associated with the decrease in alfalfa quality when cut past peak.
The optimal time to cut grasses or small grains is at the boot stage on the first cutting, Undersander said. It’s too late, particularly for the milking herd, once heads are seen.
For the second and subsequent cuttings, harvesting forages when they are primarily leaves, and not stem, is key. Thirty days is about the right time to capture the quality and the tonnage. Waiting any longer increases disease prevalence, and decreases yield and quality.
Cutting should be done down to about four inches in height, so the roots have enough energy reserves to grow quickly. Italian ryegrass is the exception, and can be cut down to the two-inch height.
“Forage quality changes on a daily basis. You have to cut it when it’s high quality,” he said. “We’re not harvesting tonnage. We should be harvesting leaves.”
Hay must be able to dry thoroughly and quickly down to the optimal level of 60 percent moisture. Plants respire in sunlight, as the stoma stay open and water is removed. But if left in the dark, the stoma close and the moisture is trapped.
In windrows, the middles aren’t exposed to sunlight, trapping moisture and remaining wet. The humidity levels inside windrows increases within 15 minutes of cutting, and can reach 95 percent.
Undersander illustrated this point by comparing windrows to throwing wet laundry in a pile to dry. But wide swath mowing is comparable to hanging that laundry on the line, on a sunny, breezy day. Wide swath is crucial to drying the forage quickly, without loss of quality.
“Respiration occurs in relation to the moisture content,” he said. “We want to shut off the fastest respiration. We’re probably not going to shut off all of it in the field.”
At 60 percent moisture, about 90 percent of the respiration is shut down. It continues, gradually declining, until about 40 percent moisture. Rapidly drying the forage from its standing moisture level in the field to the desired 60 percent level, when respiration loss becomes minimal, is best accomplished using wide swath mowing, he said.
Quick drying is important, as respiration causes the starches and sugars in the forage to break down, causing a loss of dry matter and a loss in digestibility. While the dry matter loss does cause a monetary loss per ton, it is the loss of quality of the forage, due to the change in fiber content when respiration isn’t shut down quickly, that is the primary factor in decreasing the return per acre.
While there has been controversy in regard to “hay or haylage in a day,” leaving hay cut overnight causes loss of quality, he said. Even though the plants may have slightly higher starch and sugar levels if cut in the afternoon, due to photosynthesis, the risk is that the hay won’t dry down to 60 percent moisture by nightfall. If the hay needs to be left in the field overnight, the loss of quality will be comparable to – if not greater than – the slight decrease in starch and sugar levels which would have been present in the plant had it been cut in the morning, and dried and baled by nightfall.
When cut in the morning using wide swath, Undersander estimates that the crop is dried down by evening 70 percent of the time. The lower sugar content in the morning is less important than the rapid shut off of respiration using wide swath and drying and baling quickly. While afternoon cuttings work well in drier, western regions, they do not work as well in wetter areas, such as the Northeast.
“Clearly wide swath is important. It is crucial to spread it out,” he said. “It’s more important than anything else.”
Dr. Daniel Undersander, Forage Agronomist at the University of Wisconsin, was a featured speaker at the recent 2016 Agronomy Plus Meetings, hosted by the University of Vermont. The workshops, held at various locations, and over several days, were all unique, but registered participants were provided with access to webinars of all the presentations.