Fermenting silage involves both science and art, and no two crop years result in exactly the same composition of corn silage or haylage. Severe breaches in fermentation quality, however, can result in poor-quality, unpalatable silage that also can affect rumen health.

High concentrations of butyric acid often occur when forages are ensiled too wet (dry matter content of less than 35 percent). The result is rotten-smelling silage that is less palatable to cattle and thus reduces dry-matter intake. What’s more, butyric acid breaks down into a form of ketone bodies during digestion in ruminants, contributing to total ketone loads and increasing the incidence of clinical ketosis.

Butyric acid levels can be measured via fermentation analysis. The presence of zero butyric acid in silage is most desirable.