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How Long Should Silage Ferment Before Feeding?

How Long Should Silage Ferment Before Feeding?

If you’ve ever transitioned cows to a new silage pile, you’ve probably witnessed a slump in milk production even if their ration remains the same. This phenomenon is called “bunk slump" caused by feeding out new silage that hasn’t been fermented as long as previous feeds.

To avoid milk loss with new silage, it’s crucial to understand what causes bunk slump and how it can be prevented with proper fermentation.

Why Does Bunk Slump Cause Milk Loss?

Bunk slump occurs when you go from feeding year-old silage to 30-day-old silage. This happens because the digestibility of the starch in the silage goes down. Meaning, cows have to work harder to digest their feed.

This occurs because the digestibility of the starch in your silage goes down. For example, if your old silage had a starch digestibility of 71% but the new silage only has a digestibility of 58%, your cows have to work 13% harder to digest their feed. This can impact their overall performance and a drop in milk yield.

Let’s break it down with a little science. The digestibility of silage changes because of something called zein protein which encases the starch (energy). Zein protein dissolves over time when the pH of your silage pile is lower, and when it does the amylase enzyme (in silage or the rumen) can easily access the starch and increase digestibility (available energy). However, if the pH of the silage pile isn’t low for very long, the zein protein continues to surround the starch, making it harder for cows to digest. This results in less available energy and lower performance.

How Quickly Can I Feed My Silage?

How quickly you can feed silage depends on the inoculant and fermentation time. Some inoculants take a minimum of 45-60 days to ferment, like L. buchneri. Others take merely a few days or a week. The quicker your pH drops below 4, the faster starch digestibility increases and you can feed silage to your cows without performance losses.

The chart below shows how days of ensiling (time) directly correlate with how digestible starch is in forage.

digestible starch is in forage

To select an inoculant that helps you avoid bunk slump, look for products that drop pH quickly, such as Anchor™ for Silage. Be sure to follow product directions carefully to ensure product efficacy and optimal fermentation.

A Faster Way to Ferment Forage

Agnition’s Anchor is an encapsulated inoculant blend, reinforced by Microbial Catalyst® technology, that helps rapidly lower pH levels in forage and lock in nutrients. Anchor uses a diverse blend of beneficial bacteria, each carefully selected to rapidly reduce pH within a specific range and drive efficient fermentation. Anchor is proven to get silage to a pH of 4 in a matter of days, resulting in more higher-quality feed!

Reduce bunk slump and experience the benefits of Anchor today! Talk to a forage specialist today by calling 1-855-832-0613 or buy now to get started!


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