Forage 2022: Managing Moisture: Preserving the Hay Crop |

Forage 2022: Managing Moisture: Preserving the Hay Crop

Putting up a summer’s hay crop in a timely way, for marketing or winter feeding, is full of challenges and variables that can have a dramatic effect on the end product. While rain is always welcome and needed, that extra moisture at the wrong moment in the haying process can add stress and cause a loss of quality and difficulties in storage of the hay. Too much moisture in hay when it is baled or stored can cause major losses in quality, heating, molding, losses of dry matter and nutritive value, and the possibility of spontaneous combustion, all of which can have negative effects. 

Decades ago, my grandfather spread salt on his bucker piles as a mold inhibitor and preservative before stacking them with a farmhand loader. Modern technology has given new options for achieving this end by applying various inoculants or preservatives either when cutting or baling the hay.  

“There are at least half a dozen products on the market,” Rusty Lytle said. “Personally, I use two: Dyna-Cure and propionic acid. We have also added a Harvest-tec dew simulator, which is a separate unit we use in front of the baler during dry conditions.”  

Lytle ranches near Wall, South Dakota, and raises high-quality alfalfa hay on irrigated fields along the Cheyenne River for the dairy hay market. He’s pushed his parameters far past what has been historically possible, to produce high quality hay for his customers. Hay inoculants and preservatives have been instrumental in his ability to do so.  

“Dyna-Cure and propionic acid are very different,” Lytle said. “Dyna-Cure is Lactobacillus bacteria, which forms lactic acid and causes the plant cells to quit respirating, and this causes the cells to dry faster. We apply it with our cutter, so it stops respiration immediately and also inhibits mold growth in the windrow if the hay gets rained on. Last summer we received an unexpected inch and a quarter of rain on some alfalfa we had down, and it still made twenty-two percent protein and 172 relative feed value (RFV).”  

The lactic acid working on the hay in the windrow allows it to dry faster. How much faster?  

“That’s the $10 question,” Lytle laughed.  

With so many variables from one operation to the next, it’s hard to come up with an estimate. Windrow size, type of hay conditioner used, relative humidity, temperature, and other weather factors all come into play.  

“You get a lot of benefits from applying Dyna-Cure when windrowing,” Lytle said. “We put it on every ounce of hay we put up, including grass hay.” 

The Dyna-Cure allows Lytle to bale with a little bit more plant moisture than normal; somewhere around 3-5 percent higher moisture than he would have considered safe in the past.  

“The lactic acid continues to work in the bale,” he said, “And this helps to further reduce the moisture content of the hay.” 

The propionic acid prevents mold growth, and Lytle applies this when he is baling. 

“It is a buffered hay preservative,” he said. “Basically, it is a mold inhibitor. We can bale up to 30 percent moisture with big round bales, and up to 25 percent moisture with big squares. We’ll use it if rain is expected and we want to get some hay off the ground, or if I am baling in the evening and the hay starts to get tough I turn the preservative on. Both products will lengthen baling time and increase the quality of the hay, since you can bale at higher moisture and not lose as many leaves, but the caveat is that, in my opinion, you have to have a moisture tester on your baler. If you’re pushing the moisture content, then you need real time feedback on the hay moisture, as weather conditions can change quickly and moisture content can vary from one part of a field to another.” 

Lytle says that he has reduced other feed costs thanks to the high-quality alfalfa hay he has been able to put up, which help to offset the cost of the treatments. 

“Propionic acid and lactobacillus are both things that break down forage and soften it to make it easier for the cow’s rumen to digest,” he said. “When we set out treated and untreated bales, the cattle always clean up the treated hay first. We haven’t bought cake or protein supplements in years. We also feed less hay; a cow doesn’t need as many pounds per day if the feed value is higher. A dairy that bought hay from us for a decade was able to greatly simplify their ration using our hay, corn silage and a little corn, eliminating all distillers and other fillers. Their milk production went up, butterfat was high, and their cows were healthier. Hay treatments may seem like just one more expense but they actually pay for themselves in the long run.”  

Sara Bauder, South Dakota State University Extension agronomy field specialist, said that bacterial inoculants are essentially designed to add more “good” bacteria that aid in fast fermentation and to help reduce dry matter losses in hay by improving aerobic stability (ie: stopping mold growth).  

“Most hay already contains these bacteria, as it is naturally sourced from many forage plants, and inoculants simply add an additional amount,” she said. “These bacteria may help to reduce mold growth and yeast development within bales. Overall advantages of using bacterial inoculants include the opportunity to reduce or stop mold growth, improve hay quality and palatability, and to maintain the hay’s green color.” 

Bauder advised care in the use of hay inoculants, paying attention to environmental conditions, and carefully following the recommendations given by the product’s manufacturer. Inoculants are intended to protect against small moisture changes, so using them outside those conditions can result in ineffective outcomes and a cost without benefit.  

Bauder added that hay preservatives are designed to prevent heating and subsequent dry matter losses of hay baled at higher moistures (18 percent and higher) by inhibiting growth of aerobic microbes.  

“Essentially, preservatives allow hay to be baled wetter than recommended, reducing the time it lies in the field exposed to precipitation risk,” she said. “Hay preservatives are generally applied using an aftermarket spray system mounted near the baler pick-up. Organic acids are the most common form of additives with propionic acid being the most prevalent. Effective application of hay preservatives relies heavily upon using the proper rate (dependent on moisture content and size of bale) and quality of forage. Preservatives containing high amounts of propionic acid are generally accepted as effective in reducing spontaneous heating in moist hay.”  

Again, Bauder encouraged care in the application process. 

“Research has shown that propionic acid and buffered propionic acid are not harmful to animals, but propionic acid is corrosive and can cause damage to machines and people,” she said. “Buffered acids and salts of acids have been developed to help overcome some of these issues. Both propionic and buffered forms of this acid will likely cause hay discoloration but may help protect feed value.”  

When choosing to use inoculants or preservatives, it’s important to be well-informed, and to have realistic expectations. 

“Hay inoculants and preservatives do not necessarily increase the quality of hay, but rather are designed help to maintain quality and reduce spoilage of a hay crop,” Sara Bauder said. “Both methods have mixed cost analysis benefits when used on unwrapped (not ensiled) hay bales, and the value of the hay crop being baled should be considered when determining whether to use any additives.” 

Hay Storage 

One of the biggest concerns with high moisture content when baling is overheating of the hay and the potential for a fire. Rodney Ingalls, a rancher from Maurine, South Dakota, experienced this with his millet hay in the fall of 2016. He was in Rapid City when a neighbor noticed smoke in the stackyard. By the time the flames were tamed, he had lost 1,500 bales. The smoke could be seen for a hundred miles. 

“We learned the hard way what not to do,” he said. “Never stack millet between other stacks of hay.” 

They had received little to no rain all that summer thanks to severe drought conditions, and the millet was hardly worth putting up.  

“We weren’t even going to hay it,” he said, “But we couldn’t graze it because we had no water there. We put it up just to get it off the field. It was basically all the hay we put up that year because of the drought. We put it up dry, but we happened to get 0.80-inch rain after we baled it. I waited a week after the rain before I stacked it but made the mistake of stacking it high and tight in between stacks of old hay, where it couldn’t get any air.” 

Ingalls said that his situation was not the only time he’s heard of millet hay combusting in the stack. 

“If you get a wet spring, it will even start on fire when it is a year old,” he said. “You can smell it when it starts to get warm. Oat hay will do the same thing, though it is not as bad as millet. After our fire, one of my neighbors advised just putting millet bales in single rows, or at the most, a double row with one row on top, and stacking it away from any other haystacks, where it had plenty of air.” 

Ranchers who carry insurance should consult with their agent on policy requirements on how much hay can be stored in one area. 

“I believe my particular insurance stipulates that I can’t have over 400 tons in one stackyard and the rows must be a hundred feet apart,” Ingalls said. “There are definitely stipulations with insurance on how much can be stacked in one area and how far apart the stacks have to be for this very reason.” 

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