Inoculates can improve forage quality, preservation

MADISON, Wis. — Inoculates can improve preservation of forage and forage quality, as well as potentially boost animal performance.

“Silage inoculation is directly adding silage organisms to the silage,” said Kevin Panke-Buisse, research microbiologist at the U.S. Dairy Forage Research Center. “Some inoculants are formulated for specific scenarios like forage species, high temperature stability or aerobic stability.”

Microorganisms are like an economic exchange, said Panke-Buisse at a virtual seminar organized by the World Forage Analysis Superbowl held during the World Dairy Expo.

“We feed them and they produce organic acids that allow us to keep forages edible much past their fresh date window expiration,” Panke-Buisse said.

“We sculpt the forage pile in such a way, manage it so we get the results we want and select for the microorganisms that are the most desired,” he said. “The major organisms of interest are the lactic acid bacteria group that is defined by their primary product they make which is lactic acid.”

Lactic acid bacteria are everywhere and are responsible for products such as sauerkraut, pickles and yogurt, Panke-Buisse said.

“These bacteria are defined by what they consume, what environment they live in and what they produce,” Panke-Buisse said.

“The bacteria produce lactic acid and they do that by eating the water soluble carbohydrates that are present in chopped forage and they do a really good job of it,” he said. “But they’re best at it in the absence of oxygen, which is why we have to get the silo sealed and packed tight.”

Farmers also need to look out for spoilage organisms.

“These include yeasts, molds, clostridia and acetic acid bacteria that can lead to loss or spoilage,” Panke-Buisse said.

“Using an inoculate is unique as your farm, the forage, the weather and your budget,” he said. “You have to do what’s best for your situation, and not inoculating is a valid choice.”

Using an inoculate can have really solid benefits, Panke-Buisse said, but it is not all or nothing.

“Inoculating some crops and not others to balance the cost can be a smart play,” he said.

There are a variety of inoculants available.

“One of the first things to look for is what kind of lactic acid bacteria are in the product,” Panke-Buisse said. “Lactic acid is the primary product in heterofermenters, but you’ll get other things like ethanol and carbon dioxide.”

Carbon dioxide is generally lost as a gas, Panke-Buisse said.

“Ethanol is volatile, so if you have long exposure at the face of the pile, you’re going to loose the ethanol, too,” Panke-Buisse said.

“Lactobacillus buchneri can make acetic acid from the lactic acid in the silo,” he said. “It is a very efficient route to make acetic acid to increase aerobic stability.”

Homofermenters are efficient and drop the pH faster in the forage, Panke-Buisse said.

“Unfortunately, the lactic acid doesn’t produce great aerobic stability,” he said.

There are not many single strain inoculants available to use.

“You can find homofermenter mixes, and they will be rapid and efficient,” Panke-Buisse said. “And they will generally give you better aerobic stability.”

When using alfalfa, grass or a small grain to make silage, Panke-Buisse said, inoculation shows consistent improvements in forage quality, stability and proteolysis.

“Inoculation won’t protect from mismanagement, but it will protect from non-ideal circumstances,” he said. “But you still have to put it up right, keep it covered and don’t overfill your pile. Always remember poor pile maintenance and bad silage charges interest usually through your milk check or vet bills.”

Making silage from corn, sorghum or sugarcane is a little different situation.

“Corn has abundance of natural lactic acid bacteria, and it will ferment just fine on its own in many cases and especially with ideal scenarios,” Panke-Buisse said. “If aerobic stability is a concern for you, lactobacillus buchneri will be your friend.”

Researchers are involved with projects that are evaluating the animal performance benefits from the use of inoculants.

“The mechanism could be related to increased digestibility, increased dry matter intake, more favorable split in protein fractions or better preservation of water soluble carbohydrates,” Panke-Buisse said. “This is something we’re actively working on.”

Animal performance benefits aren’t guaranteed, Panke-Buisse said.

“But it should be in your mind as you weight the cost benefits of your silage inoculation,” he said.