This episode “Buffers and Alkalizers to Improve Rumen function and Performance” was recorded at the 2025 Florida Ruminant Nutrition Symposium Mini-Symposium
Episode 154: Buffers and Alkalizers to Improve Rumen function and Performance
Timestamps:
Dr. Bach gives an overview of his presentation, highlighting that buffers make the rumen resistant to a decrease in pH while alkalizers immediately increase rumen pH. He prefers magnesium oxide, an alkalizer, over sodium bicarbonate, a buffer. Both are effective, but sodium bicarbonate requires a larger amount, thus taking up more room in the diet. The magnesium oxide must be of high quality and soluble in the rumen. (3:40)
Dr. Richards asks if we should use magnesium oxide more as a first line of defense against acidosis. Dr. Bach notes that the very best strategy is to avoid using either additive by making a proper ration balanced in terms of amount and rate of degradation of starch. But there are many constraints in the field, so he recommends using magnesium oxide before sodium bicarbonate. For the magnesium oxide to be effective, it must be solubilized in the rumen to magnesium hydroxide, and solubility can be tested in a variety of ways to determine quality. (7:35)
The panel discusses the impact of magnesium oxide in place of sodium bicarbonate on DCAD and which DCAD equation(s) should be used for calculations. Dr. Bach recommends removing sodium bicarbonate from rations containing less than 1% of the ingredient. It will have little effect on the rumen, but make room in the ration. The panel explores how this can impact farm-level economics. (12:39)
Dr. Bach also mentions probiotics and their impact on rumen function. In vitro studies have shown a wide variety of modes of action and positive results. Extrapolating in vitro doses to the cow often results in unsustainable amounts of the additive needing to be fed. Applied studies at the cow level have yielded inconsistent results. (23:29)
Scott asks how long Dr. Bach has been making the case for pulling sodium bicarbonate out and putting magnesium oxide in, and what kind of pushback he has received. Dr. Bach gives some of the reasons farmers have given for not wanting to make this management change. He also notes that farmers who do make the switch do not tend to go back to sodium bicarbonate. (25:18)
Dr. Bach and Maimie discuss grass silage diets and grazing diets with high amounts of moisture and how best to combat acidosis symptoms with those. In diets like this, where you’re not trying to make room for energy, sodium bicarbonate can be a good choice. Dr. Richards chimes in with questions about the ratio of the two ingredients; Dr. Bach indicates the ratio doesn’t mean much to him. (26:16)
Panelists share their take-home thoughts. (33:27)
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