Pioneer Hi-Bred’s Jim Smith provided information about managing silage feedout in hot weather in the trending topic article, "Maximizing silage feed value during hot weather requires extra management." Click here to read it. Because this article has been so popular, we reached out to Pioneer to respond to a followup question: Q. Many areas experienced warmer-than-usual winters and springs. What advice do you have for feed storage this summer when temperatures have already been a bit higher the whole year?

With the onset of summer comes high heat and humidity! Heat and humidity often spells trouble for livestock, reducing feed intake and slowing production. There are a number of things producers can do to help animals during these times. Placing fresh, cool feed in front of animals is a key management practice that will help reduce problems due to heat stress.

One of the biggest challenges of hot weather is feed stability. As silage is re-exposed to air, yeast and other silage organisms begin to grow again. Periods of high temperatures lead to accelerated rates of yeast growth and eventually mold growth.

In the biological world, every 10 degree increase in temperature leads to a doubling of the metabolic rate of organisms. If for instance your corn silage has a stable temperature of 70 degrees, then increasing air temperature on the silage face to 80 degrees results in a yeast growth rate that is 2X of normal.

Now increase it to 90 degrees and your growth rate is 4X. As yeast grows, it consumes lactic acid. When enough lactic acid is consumed, silage pH increases and allows molds to begin growing, leading to further instability and feedout concerns.


One indicator of unstable feed is a fingernail polish smell coming from the forage. This indicates the activity of aerobic organisms and can lead to palatability problems at the bunk.

Silages that were ensiled using proven strains of L. buchneri will greatly slow down this process. The L. buchneri bacteria produce acetic acid which dramatically reduces yeast growth and helps keep feed stable for many days after exposure to air.

Here are five keys to managing summer heat and forage stability:
• Accelerate the removal rate from the silo face. Normal recommendations for silage removal are 6 inches per day. In hot weather, try to remove 12 or more inches per day. This is especially important when a proven inoculant was not used, packing was inadequate, or silage was dry when ensiled.

• Leave excess plastic on bunkers and let it hang down over the face of the silage to keep the sun and rain off of it.

• Keep your face clean. Removing silage from the top down using a silage facer reduces the amount of air penetration into the silage mass. Clean and feed all loose silage as soon as possible.

• Remove and dispose of all moldy and musty silage prior to feeding good silage.

• Keep feed bunks clean and dry, feeding TMR mixes 2-3 times per day and frequently sweeping up feed in the bunk.


Daniel Wiersma
Livestock Information Manager
Dupont Pioneer