Those who feed their cows on pasture want to do right by their animals. They want to make sure they’re eating a healthy mix of greens and getting all the proper nutrition to grow big and become profitable. But sometimes finding the right combination of forages and supplements is like trying to solve a Rubik’s cube in the dark.
Researchers have been working to help shine a light on the issue. Discussing “Maximizing Beef Cow Efficiency with Variable Forages” at this year’s CattleCon were Dr. Kip Karges and Dr. Melissa Jolly-Breithaupt of Lallemand Animal Nutrition. The focus of their talk wasn’t the forages themselves but the tiny organisms that make them more useful.
“Where would our world be without yeast?” Karges began.
Jolly-Breithaupt continued that train of thought, noting that both yeast and bacteria need to go into cows’ digestive tracts to results in “happy fermentation.”
A lot of focus in diets (in both humans and livestock) is put on protein and energy, but fiber is equally important, especially for diets that are mostly vegetative.
Jolly-Breithaupt explained there are specific nutrient requirements for most cattle: 8% to 12% protein and 2% to 5% vitamins and minerals, with the rest of the pie likely being fiber.
“Lignin is not digestible,” she said. Lignin is in a class of complex organic polymers that form key structural materials in the support tissues of most plants. They’re important in the formation of cell walls, especially in wood and bark – and also sturdy forage stems – because they lend rigidity and do not rot easily. Cows need yeast in their rumen to break lignin down to get to the cellulose and hemicellulose of plants – natural sugars that provide energy.
Yeast can be boosted by prebiotics (fuel for existing microorganisms), probiotics (live organisms that will trigger a response) and postbiotics (blends of the other two).
“It’s all about the passage rate of grass,” Karges said. “If it goes through fast, there’s no time to absorb energy.”
As representatives of the company, the duo mentioned Lallemand’s LEVUCELL® SC, a specific strain of yeast (Saccharomyces cerevisiae CNCM I-1077) that “stimulates the growth and colonization of fiber-digesting microbiota, improving the availability of nutrients.” They were described as “highly selected organisms to do a specific job.”
Karges said the company conducted a study with this strain of yeast in summer 2023 with mama cows on pasture. They started feeding it to them 30 days prior to calving, and then they looked at the animals’ body condition scores at the end of weaning. Overall, they saw an improvement of half a BCS score – an average of 22 lbs. better. The product was fed free choice to 400 head.
The key is to remember “the bugs are what you’re trying to influence, not the cows,” Karges said.
Most yeast products will stay alive and stay active for a while, and Jolly-Breithaupt said they can be mixed with any mineral and can be fed year-round.
“We’ve seen 20 years of positive growth on the dairy side in TMRs” with yeast supplementation, Karges said. “And now we’ve tried it on the beef side for another success.”
Speak with your herd nutritionist or veterinarian to find out which strain of yeast might work well for your herd as they work their way through their pastures this grazing season.
