We have long known that the best corn silage takes 60 to 90 days to properly ferment. The same might be true for high-moisture corn, a highly variable energy source for dairy cows.
Nature never intended corn as a feed; it’s a seed designed to keep energy locked up in the form of starch until the spring, says Pat Hoffman, a University of Wisconsin dairy nutritionist.
The starch is protected by a tough cover called the pericarp. “Corn pericarp is relatively resistant to rumen bacteria, and whole corn seeds with the pericarp intact are largely indigestible in the small and large intestine of ruminants,” Hoffman says. The starch is also protected by a complex starch-protein matrix. The proteins repel water, keeping the starch from degradation.
Current harvest techniques don’t enhance fermentation. High-moisture corn is often harvested at 30% moisture, or less, in mid to late fall, when temperatures are less than 50°F. “The combination of limited substrate for fermentation, high dry-matter content and ensiling at cooler temperatures suggests high-moisture corn fermentations are destined to be protracted,” Hoffman says.
More research, of course, is needed. In the meantime, Hoffman has the following recommendations:
- Understand your hybrids. If one has a shorter relative maturity, harvest it first.
- If a hybrid has a hard, vitreous endosperm, harvest earlier and process more to optimize fermentation.
- If possible, harvest and ensile at warmer temperatures to enhance fermentation. Also inoculate if you can.
- Understand that high-moisture corn is not a static feed. Adjust rations throughout the year to accommodate the increasing starch availability as the corn ferments.