Last month, we explained the advantages to feeding plain grains. However, it’s key that you choose good-quality grains. The easiest way to do this is to insist on buying only grains that are USDA grade 1.
USDA grades are based on the weight/bushel, presence of heat damaged or broken kernels and foreign material. The lowest grade, not suitable for feeding to any animal, under any circumstances, is “sample grade.” Grade 1 is the best grade. Never feed grains with a grade of 3, 4 or 5 to a horse (there are four USDA grades for oats and five for corn). Our table (see sidebar) list the characteristics of oats and corn.
In addition to the numerical grades, several special grades exist that will be present on the grading sheet accompanying the grain. Some special grades are desirable, as is “bright oats,” which just means the oats have a naturally bright color. Others are undesirable: infested (bugs), ergoty (a dangerous fungus), smutty (an off odor), and thin oats.
Grade 1 and grade 1 heavy or extra heavy oats are sometimes called “racehorse oats” or Canadian oats. Many of the highest-quality oats are imported from Canada or grown in the northern-tier states in the United States.
A final quality consideration for oats is that they should be triple cleaned. This process removes contaminating dirt, empty hulls and dust from the grain.
For corn, undesirable special grades are flint corn (extremely hard outer kernel), infested (bugs). Always insist on corn that has a moisture content less than 14% to help minimize chances of molding.
Little is known about the effects many common molds and their toxins have on horses. Grains with mold contamination have the potential to produce digestive upset, organ damage, even death from irreversible brain damage in the case of some corn molds of the Fusarium species.
Levels of mold growth invisible to the naked eye can cause problems. Buying the highest grade grains is a big step toward avoiding mold problems. Grains that have their husk intact are highly resistant to molding, while cracked grains, broken grains and grains with loose husks are susceptible.
Fatal moldy corn poisoning is most likely to occur when feeding corn that was grown during a period of drought but harvested under wet conditions. Low-moisture grains are less susceptible to molding during storage.
If you’re going to be buying your corn in quantity, you might consider an assay for fumonisin, the potentially fatal toxin produced by the Fusarium molds. Cost for this assay is $25 from Dairy One (www.dairyone.com, 800-496-3344). More comprehensive mold assays are also available, but this is the one of most concern at low levels. Safe levels for a horse are less than 5 ppm when the corn is 20% or less of the total weight of the diet.
You can also get information regarding the level of Fusarium problems in the area where your corn was grown by calling the state agricultural extension office or your state university’s agricultural department.
Some people choose not to feed corn at all because of fear of toxicities. An alternative whole grain/food diet that doesn’t include corn but is balanced for major minerals would be a 50:50 blend of beet pulp and whole oats, or 30% alfalfa pellets and 70% oats.