NOTICE: From time to time, supplies of Certified Organic Seed run out. When this occurs, we use the organic seeds (in a mixture) that we still have and then use Untreated non-GMO seed for the remainder of the mixture. We will then issue a non-GMO letter upon request.

One of the obstacles to dairying organic is the cost of Certified Organic corn/silage. Choosing to grow floury corn which is gaining a lot of push on the conventional dairy side—provides a huge bonus for organic dairy farmers as well.

Advantages of Floury Corn

Floury corn has a number of advantages compared to the flinty corn that is by far the most common type of corn in the industry. The first advantage involves what is commonly known as the "fall slump" that is experienced when feeding new vitreous crop corn silage soon after harvest. With vitreous corn, the hard endosperm limits the availability of the starch portion of the corn, which is 70 percent of the weight of a corn kernel and the major source of the glucose needed for milk production. The difference in starch availability which can start at more than 20 percentage units higher in floury corn—narrows after months of cooking in the effects of fermentation-produced lactic acid, but it still persists to some extent through the feed-out period.

The second advantage of floury corn involves the grain fed as concentrate. The fineness of the grain and moisture also affect the availability of the starch. However, work at Michigan State University by Allen et al. shows that even with variability of grind and moisture, floury corn still has advantages (see chart).

Rate of Starch Passage

This study shows that the difference in starch availability remains in the shift between high-moisture corn and dry corn. The data shows that the floury corn remains in the rumen longer and therefore is further digested ruminally than vitreous corn. The floury (less dense) corn stays in the rumen mat during its digestion; by contrast, the harder, denser vitreous corn escapes the rumen and ultimately ends up in the manure—a poor place to accumulate $8-a-bushel organic corn!

Look at It in Practical Terms

In practical terms, higher starch availability—whether in the corn silage or the concentrate portion of your cow's diet—gives you more credit for the starch you raise (or buy). Say two corn hybrids—one floury and one vitreous—have the same percentage of starch. The starch is the same, but the availability is much different (by as much as 20 percent). So your cows receive more glucose-producing starch while you feed less corn! When a bushel of Certified Organic corn costs more than $8, the economy is compelling!

How much corn is in your corn silage?

Starch is always very close to 70 percent of a corn kernel by weight. Therefore, to approximate how much of your corn silage is actually corn, simply divide the starch percentage by 70.

For example, if the starch percentage from your feed test is 35 percent, then 35/70 equals 50 percent. So your corn silage is half fodder and half corn. If you are feeding 15 pounds of corn silage DM, for example, you're feeding 7.5 pounds of corn.

If your starch is 28% divided by 70 = 40% of your DM corn silage is corn.