Dealing with the transition to new silage
Oct 03, 2013
Starch can play a major role in your cows’ performance. This is certainly true when it comes to feeding new-crop corn silage. It’s common in these situations to see a drop in milk production, even though the ration formula has not changed. The origin of the problem can often come down to starch variability in the corn silage itself, as well as variability in the starch available to the rumen microorganisms.
Crude starch and rumen digestible starch are two ways to measure starch levels in the diet. Crude starch measures how much starch is present in the feed. Rumen digestible starch gives you an idea of how much starch is actually available to the rumen microorganisms. Knowing this is valuable for managing the effects of switching to new-crop corn silage.
For example, if rumen digestible starch scores from the new-crop corn silage show it is lower than starch scores from the previous crop, you can expect the starch to be less available in the rumen and to the cow. Cows respond to lower rumen digestible starch by producing less milk and higher components. The lower production response associated with switching to the new silage can last one to two months.
However, if you test for starch digestibility before feeding the new crop, you know what you’re up against and can take action accordingly. If you find yourself with low scores, you can try leaving the new corn silage in storage longer. Over time, starch availability of stored corn silage improves. Or, you might try replacing the corn silage starch with a feedstuff that has greater rumen digestibility or higher starch content.
Remember, starch availability can vary significantly from year to year, but when you make ration changes with consideration to rumen digestible starch it can help you keep rations consistent and avoid hiccups in your cows’ performance.