Last Year’s Corn May Be Nutritionally Deficient
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Last year’s corn crop ended up being a bumper crop despite early expectations, thanks in part to the extended warm weather in the fall, but the wet conditions during the growing season and throughout harvest may have reduced the nutritional value of the crop, according to the Poultry Science Association.
“Adverse growing conditions and the potential for reduced bushel weight are one component of the corn quality equation. Unfortunately, determining a precise relationship between variability in bushel weight and the nutritional value of corn is problematic,” said a poultry nutritionist from the Ohio State University.
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Whenever poor growing conditions are present, variations can be found in the bushel weight or in the test weight of the corn. Since the bushel weight is commonly used as a measure for pricing, it’s thought to represent a variety of factors that make up the density of the corn, such as the assumed quality.
Because nutritionists are aware of the variability in the nutritional value of commodity grains, depending on the growing conditions, analytical testing measures are routinely used to determine the moisture, fat, and protein content of the grain, and to adjust nutrient matrix values as needed. However, these tests are incomplete, as they do not accurately reflect the nutritional value derived by the animal through ingesting the grain.
If corn is harvested while it has above average moisture content, as was the case this past season as the harvest extended into the early winter months, more extensive drying is required before the grain can be safely stored. This, too, has an impact on quality issues.
Says the Poultry Science Association representative: “Buyers should be on the lookout for corn coming in with moisture levels lower than they typically see, as this may be an indication that corn was dried down quickly at higher than normal temperatures.”
High drying temperatures can cause nutritional damage to the corn, making it more difficult to extract individual proteins even thought the gross chemical composition of the corn remains virtually the same. Studies done in 1994 evaluated the amount of time it took to dry corn that had been exposed to a range of moisture levels – from 12% to 30% – and found that the nutritional makeup was impacted once corn was dried at a temperature of 80C and higher.
