Q. Last year, our farm was short on forage from the previous year, so we switched over to the current year’s harvest rather quickly and saw a noticeable decrease in milk production. I think this switch caused the decrease. How long should I leave this year’s silage pile before I start feeding it?
A. Switching to newly fermented silage can certainly lead to a drop in production, especially if the new silage was not stored long enough.
The silage should be left for at least 30 days before feeding. For best results, allow the silage to ferment for at least four months before opening it and feeding. This allows for optimum starch digestibility as the prolamines in the starch-protein matrix of the kernels are broken down over longer storage periods. If you open up for feeding sooner, be aware the starch digestibility will change over time. To avoid issues like sub acute ruminal acidiosis (SARA), have your nutritionist test the starch digestibility at least once a month to determine if any ration adjustments are required.
To minimize milk production decreases, it also is important to gradually make the switch from the previous year’s silage to the new silage. One common protocol is to change 25% of the ration silage per week or every two weeks, for example zero new silage; 25% new; 50% new; 75% new; 100% new. This helps cows better adjust to the differences in dry matter levels and nutrient content.