In this month’s article, I want to share a question I recently received from a Tennessee cattle producer. He had a bunker of silage that was six to seven years old and was wondering whether it was still safe to feed to his cows. His concern was not only about feed value, but also whether the silage could pose any health risk to the herd.

This is a fair question and one many producers may face. Silage is a valuable feed resource, and none of us want to waste it if it can still be used safely and effectively. The good news is that silage does not automatically become unsafe simply because it is old. However, age does increase uncertainty, and careful evaluation is essential before feeding.

The first and most important factor to consider is how well the silage was stored. Properly made silage that was well packed, adequately covered, and remained sealed can stay stable for long periods of time. The key is maintaining anaerobic conditions. If oxygen is kept out, fermentation products help preserve the silage. On the other hand, if the plastic cover was damaged at any point—especially along the top, shoulders, or sides—oxygen can enter and compromise large sections of the bunker.

Before any testing, producers should start with a basic visual and smell assessment. Silage that appears slimy, excessively dark, heating, or has a strong musty or rotten odor should not be fed. Any visibly moldy material should be discarded. Even if only a portion of the bunker is affected, it is important to avoid blending spoiled silage with good material.

I do agree that a forage analysis is a necessary first step to determine feed value. However, a standard forage test alone does not address potential safety concerns. It will not detect mold-related issues or toxins that could affect cattle performance and health. For older silage, I recommend adding yeast and mold analyses, and when there is any concern about aerobic spoilage, a mycotoxin assay. These tests can provide valuable insight into whether the silage poses a risk to cattle.

If test results indicate the silage is acceptable, it should still be introduced gradually and fed at a limited inclusion rate. I would avoid feeding older silage as the primary forage source and use extra caution with high-risk groups such as lactating or bred cows.

In summary, age alone does not make silage unsafe, but a few years of storage requires a cautious approach. Evaluating bunker integrity, conducting visual assessments, and combining forage quality analysis with mold and toxin testing will help you to make informed decisions—protecting your cattle.