Despite producers’ best efforts, sometimes silage will succumb to yeasts, molds and other microbes that cause spoilage. Including this damaged feed at low rates is tempting, but even small amounts can disrupt normal rumen function — and can lead to reproduction problems or impaired cattle health.

“Disposing of the spoiled silage can feel like throwing money away, but it may be the best solution to avoid further problems,” says Bob Charley, Ph.D., Forage Products Manager, Lallemand Animal Nutrition. “Molds in feed can cause respiratory problems, reduce intake and negatively impact production. Furthermore, some common spoilage molds may produce mycotoxins under certain circumstances, which can cause serious health issues.”

Dr. Charley warns that feeding even small quantities of spoiled silage can lead to drops in intake, acidosis-like symptoms, reduced fiber and dry matter (DM) digestibility. In dairy herds, milk production and fat depressions also are common.

A study by Kansas State University incorporated various levels of spoiled silage into the ration of steers. Including just 5.4 percent of badly spoiled silage in the ration of beef steers reduced DM intake by 1.3 lbs. per day.1

“Limiting or preferably eliminating spoiled silage is the best bet for maintaining production, herd health and preserving valuable feedstuffs,” Dr. Charley notes. “There’s no substitute for the basics of good silage management.”

To achieve this goal, he recommends producers:

  • Start with good quality forage, harvesting at the right stage of maturity and moisture level,
  • Set theoretical length of cut to achieve the right chop length and check actual particle size distribution,
  • Treat all forages for silage with an inoculant that has independent research data to support that it will achieve your objectives,
  • Pack, pack and pack well to exclude air,
  • Cover and seal well immediately, taking care to repair any damage to silage plastic during storage, and
  • Manage feedout by removing six inches or more from the face, keeping the face straight and clean and avoiding leaving drop (compost) piles.

In particular, Dr. Charley recommends using a research-proven forage inoculant to help prevent aerobic spoilage. Inoculants that contain Lactobacillus buchneri 40788 at an effective dose can help address stability challenges at feedout. In fact, high dose rate L. buchneri 40788 is reviewed by the FDA and allowed to claim efficacy in preventing the growth of yeasts —the main cause of silage heating and the initiators of aerobic instability — and molds in silages and HMC.

“Spoilage yeasts occur naturally in varying numbers on all pre-harvest crops,” Dr. Charley notes. “If these yeasts become dominant, they can start the process of aerobic deterioration — raising the forage pH, which allows for further spoilage by molds and bacteria. To win the microbial war in your silages, it’s important to use proven forage inoculants containing fast acting, efficient homolactic acid bacteria. This loads up your silage with an army of billions of these good microbes and helps ensure the right balance is in place.”

1 Whitlock LA, Wistuba T, Siefers MK, Pope RV, Brent BE, Bolsen KK. Effect of level of surface-spoiled silage on the nutritive value of corn silage-based rations. Cattlemen’s Day 2000. Accessed May 21, 2015. Available at: