As rumen health takes center stage in today’s high-producing herds, buffers are gaining renewed attention for their role in stabilizing fermentation, supporting intake and easing heat stress. That’s the message from Mike Hutjens, professor emeritus at the University of Illinois, who recently joined the Dairy Nutrition Black Belt Podcast to unpack the science, use and economics behind this essential feed additive.
Why Buffers Matter
Hutjens notes buffers are more than just insurance against acidosis, they are foundational to maximizing microbial efficiency and cow performance.
Despite the fact that buffer use is widespread on U.S. dairy farms, many producers still don’t realize just how pivotal they are to rumen function. According to Hutjens, 38% of farms include buffers in the ration — making them the most commonly used feed additive in the industry.
“That number typically stays right around the 40% level,” Hutjens says. “It’s consistently the most popular additive year after year.”
So, what makes buffers such a staple?
“We’re trying to optimize rumen fermentation,” Hutjens explains. “That’s the beauty of our dairy cow. Buffers help stabilize the rumen environment, which is critical as 70% to 80% of the cow’s energy comes from volatile fatty acids produced by rumen microbes. Plus, over 60% of the amino acids the cow uses are synthesized by those same microbes. If we can keep a healthy rumen, then we usually have a healthy cow.”
The “Big Three” Benefits of Buffer Use
Hutjens outlines three primary reasons why nutritionists and producers include buffers in dairy diets:
- Stabilize the rumen environment. Buffers help maintain an optimal rumen pH, which is especially important when feeding high-energy, highly fermentable rations. A stable rumen pH encourages fiber digestion and supports microbial health, resulting in better nutrient utilization.
- Increase dry matter intake. Several studies have shown buffers can stimulate appetite, leading cows to eat more. And more intake generally means more milk.
- Manage heat stress through DCAD strategies. Especially in warmer months, dietary cation-anion difference (DCAD) management becomes critical. Buffers, particularly those containing sodium and potassium, help raise DCAD levels to improve rumen function and reduce the effects of heat stress.
“Increasingly, DCAD and summer heat stress is a big one,” Hutjens emphasizes. “We’re looking typically at trying to get our DCADs up to a plus 300 milliequivalents per kilogram of dry matter. That usually involves a combination of sodium bicarbonate and potassium carbonate.”
He cautions producers not to assume cooler climates are immune to heat stress.
“We tend to think, ‘Oh, there’s no heat stress here in the upper Midwest,’ right? But that’s not true at all,” he says. “More and more of those high-producing cows require lower and lower temperatures. Even small temperature increases can have a significant impact.”
Buffer Options: More Than Just Sodium Bicarb
While sodium bicarbonate (bicarb) remains the gold standard, Hutjens encourages producers to understand the full range of buffer and alkalizer options available.
“Some are true buffers, like sodium bicarb, which has a pKa of 6.25. That’s exactly where you want the rumen pH to be,” he explains. “Others are alkalizers, which help neutralize acids but don’t have the same buffering curve.”
He provides a breakdown of the five most common buffer or alkalizer sources:
Sodium Bicarbonate: The most widely used and studied buffer, bicarb helps maintain rumen pH around 6.0 to 6.25, which is ideal for fiber-digesting bacteria. Hutjens recommends including it at 0.75% of total ration dry matter.
“As cows eat more, you’ll need to increase the bicarb to maintain the correct balance,” he notes.
Sodium Sesquicarbonate: A 50/50 blend of sodium bicarbonate and sodium carbonate, this ingredient offers both buffering and alkalizing properties.
“Some companies prefer this product because it can be priced slightly lower per ton,” Hutjens adds. “The research looks quite good, and the feeding rates are generally the same as bicarb.”
Potassium Carbonate: This is typically twice the cost of sodium bicarb, but highly effective, particularly for boosting DCAD.
“Studies out of South Carolina showed potassium carbonate outperformed both bicarb and potassium chloride in buffering ability,” he shares.
Magnesium Oxide (Mag Ox): A buffer that is commonly used as an alkalizer and source of magnesium. Hutjens cautions that performance depends on factors like solubility, particle size and heat treatment.
“There’s a new mag ox product coming out of France that claims to be more stable and longer-lasting,” he notes.
Calcium Carbonate: Often confused with limestone, calcium carbonate plays more of a role in the lower GI tract than in the rumen.
“Research at Illinois shows it doesn’t do much in the rumen,” Hutjens says. “A new, highly soluble version extracted from seawater off the Irish coast is gaining attention for use in dry cows, as it doesn’t affect DCAD.”
Know What You’re Feeding
One of Hutjens’ most practical takeaways is a call for producers to ask what’s actually in their buffer packs.
“Most farmers are going to go with a commercial product from a feed co-op, company or consulting group,” he says. “But the question is: What is in that buffer pack? You may be feeding 200 grams, or half a pound, but is it all limestone? That would make it very economical, but probably not very efficient.”
Higher-value ingredients like potassium carbonate or sodium bicarb may cost more, but they also do more to stabilize the rumen. And unless the correct levels are fed, their benefits won’t be realized.
Hutjens adds that buffer packs may also contain other ingredients, such as yeast cultures or carrier feeds. That makes it even more important to review product specs and ask for a breakdown.
Buffers are Tools, Not Band-Aids
While buffers can play a powerful role in nutrition programs, Hutjens warns against using them as a band-aid for bigger ration issues.
“I get nervous when someone uses a buffer to try and raise butterfat,” he says. “Usually there’s a bigger problem in the ration that should be addressed first.”
Buffers are best used as part of a comprehensive feeding strategy, one that supports a healthy rumen, optimizes intake and helps cows cope with stress.
“Ultimately, if you don’t know what’s in your buffer pack, you may be saving money, but missing out on performance,” Hutjens concludes.
