When Kurt and Jay Mairs of Wooster, Ohio, sit down with their nutritionist and agronomist to pick seed for corn silage and grain, the scene is nothing out of the ordinary. After all, this sort of event happens annually on dairy operations that raise their own corn for grain and silage. Yet there is something different about their seed-selection sessions compared to years past. As they pour over the hybrids, they now look for grain and silage varieties with compatible starch degradability rates.

The Mairs participate in a feeding program available to Land O’Lakes Purina Feed customers. The program helps them “synchronize” fast and slow starch degradability rates. The goal in doing so is to optimize starch degradability in the rumen and achieve more consistent herd performance, says Allen Johnson, a large herd specialist with Land O’Lakes Purina Feed and the herd’s nutritionist.

You can get more out of your corn, too. Here’s a look at the Mairs’ program and other practices that optimize starch degradability. 

Blend compatible corn hybrids

Last fall, the Mairs harvested hybrids expected to deliver a certain rate of starch degradability. They harvested one variety of corn silage and two varieties of corn grain for high-moisture and dry corn. At harvest, they stored each grain hybrid in separate bins to preserve its identity. Johnson submitted samples from each bin for a starch-degradability analysis. The lab results verified the speed of starch degradability of each grain hybrid. Johnson uses that information during ration balancing. It helps him blend the right amount of each grain hybrid with the Mairs’ corn silage to keep the speed of starch degradability in the rumen as consistent as possible. They continually strive to increase components while maintaining the herd’s milk production. Results have never been more consistent, Johnson says.

The Mairs also use the concept of “fast” and “slow” corn to troubleshoot production problems. When butterfat levels in their 300-cow herd dropped, they traced it back to their corn silage. As it turns out, the corn silage had been in storage for awhile, which caused the starch in it to be degraded rather quickly in the rumen, Johnson explains. To correct the problem, they paired this “fast” corn silage with corn grain expected to have a slower starch degradation rate.

Manage the variables

The starch degradability of corn is a function of three principle components, says Pat Hoffman, dairy scientist at the University of Wisconsin’s Marshfield Agricultural Research Station. Those factors include moisture content at harvest, particle size and endosperm type. In a sense, they are like pieces of a puzzle. Fit them together to better control the speed of starch degradation in the rumen.

The appropriate rate of starch degradability to aim for is a decision only you and your nutritionist can make. Just remember, too fast is not good and neither is too slow. “Somewhere in the middle is where you want to be,” Hoffman says. (For more details on achieving a balance between fast and slow degradability, please see “Achieve a good balance in the rumen” on page 29.)

Managing the rate of starch degradability of corn grain and silage is “one more known that you can lean on,” Johnson says. For the Mairs, “one more known” in their nutritional toolbox helps them get more out of today’s $7 corn. Discuss with your nutritionist how to best achieve the same goal. 

Cows in Kurt and Jay Mairs’ herd get more out of their ration thanks to a feeding program that coordinates corn grain and silage based on its rate of starch degradability.


Achieve a Good Balance in the Rumen:


If you want starch to be degraded more quickly


If you want starch to be degraded more slowly


Harvest corn grain at higher moisture levels.


Harvest corn grain at greater maturity (so it’s more dry).


Aim for a finer particle size.


Use processing techniques that result in a more course particle size.


Choose an endosperm with less encapsulation

(which makes it more available in the rumen).

Choose an endosperm with more encapsulation.


Allow corn silage or grain to ferment longer.


Reduce storage time so starch doesn’t ferment as long.