It’s getting warmer-which is great! But the feed is heating up too…more than it should. This is the time of year wild yeast waits for.  Wild yeast that was in the feed when it was put up, can suddenly explode in warmer weather. Unfortunately, this isn’t the same strain of yeast you buy to feed the cows to stabilize the rumen. These strains have a negative impact on rumen function and can cause loose, inconsistent manure and decreased dry matter, milk and butterfat test.

Controlling wild yeast can be tricky, but there are a few things that will help reign them in:


1.  Maintain a smooth face.

Reducing air exposure is key to reducing yeast counts. Smooth faces on bags, piles and bunkers can reduce the air that helps the yeast go crazy.

2.  Increase the removal rate of the feed.

Increasing the removal rate from 6-12 inches a day to 12-18 inches will help feed the infected feed faster. But wait a second, don’t feed more to the lactating cows! They’re already struggling with the feed. Feed it to animals on the farm who are not under as much stress-like heifers. The effects of the yeast are minimized for them.

3. Don’t make a separate pile to feed later.

Many people make separate piles to feed later in the day-or premixes to feed later. If the premix or prepared mix contains the infected feed, the yeast will explode. This is especially true if you mixed the feed with any kind of sugar, like molasses or whey permeate.

4.  Feed regular yeast

I know, it seems counterintuitive. But the best attack against wild yeast strains are their enemies-domestic yeast strains. Remember though, you need to add enough to give them a chance in the fight-sometimes up to 3 times the recommended amount.

5. Feed a buffer

Buffers help stabilize the rumen while you’re working on a solution for the yeast.

6. Use a preservative containing acetic acid

Acetic acid kills yeast. Most preservatives contain proprionic acid and improve bunk stability. Most yeast problems can be controlled by mixing in one of these products. For severe yeast infestations, acetic acid is more effective. Try for a blend of both.