As farmers scramble to harvest their corn before winter sets in, many are finding light test weight corn in their fields. However, if this corn can not be utilized by the ethanol industry or mills, it still has a use in the beef industry, according to a University of Nebraska specialist.
“Many factors can cause light test-weight corn,” according to Matt Luebbe, who recently presented a webinar on utilizing light test weight corn. “In fact, my counterparts in North Dakota have a saying that ‘Corn production is a race against time’.”
“Growing conditions and management strategies can have a large impact on corn characteristics,” Luebbe continued. “If conditions are less than optimal, it can reduce quality or value of corn grain.” Early frost, fewer warm days, hybrid selection, and planting date can also reduce the quality and value of corn.
What causes light test weight corn?
While drought is almost certain to be a factor causing this year’s lighter test weights, test weight is also influenced by leaf disease, ear rot, hail, and germination, he explained. Hybrids that are region specific and need a particular growing season can also yield lower test weights, as can temperature, he added.
“In parts of the Midwest, optimum grain production may only be achieved 50 percent of the time,” Luebbe said. “When corn is less than optimum, producers are left with the decision of how to best utilize this resource most efficiently.” This year, Luebbe said farmer-feeders harvesting light test weight corn may have an economic advantage by feeding it to their cattle.
Studies conducted in 1992 and 1993 at the University of Nebraska indicate dry matter intake for low test-weight corn to be less than normal test-weight corn. Average daily gain was actually higher with low test-weight corn, and feed efficiency also favored feeding low test-weight corn.
Based on this research, Luebbe said producers with the option of feeding low test-weight grain may be at an advantage, depending upon what the marketplace is discounting low test-weight corn. Looking into this further, Luebbe has seen fairly large discounts, and some corn rejected once it is 48 pounds or lower. “Cattle producers can take advantage of this discount to purchase some corn that the ethanol plants or other mills can’t accept,” he said.
While corn processing can maximize starch availability, it can also lower the cost of gain, and increase feed efficiency, Luebbe explained. The kernel characteristics may change the shape, but different processing may be needed to make more starch available, he said. “The unknown question is does it change the degree of processing, and what is the impact on animal performance with low or normal test-weight corn?” Luebbe is the first to admit little research has been conducted in this area.
Nutrient density doesn’t equal the rate of digestibility, Luebbe continued. An increase in digestibility usually results from processing the corn, which allows the animal to make more use of the corn’s nutrients. “Processing grains may be a critical factor in the value of them,” he concluded.
Depending upon the species of animal, some are able to utilize low test-weight corn more efficiently than others. “Data is inconsistent with non-ruminants, but generally shows a decrease in energy value and feeding value with low test-weight corn,” he says. “Meanwhile, ruminants maintain an advantage because they have greater utilization of the pericarp, or the bran. Even through it is a low proportion of the kernel, it provides energy to the animal. The pericarp, in growing diets, can be of value.”
The larger the kernel, the greater proportion of starch to pericarp, Luebbe continued, which increases digestibility. “Just because the test weight of a grain is low doesn’t always mean it will cause a reduction in performance,” he said.
Cattle can still utilize corn with mycotoxins
During a year when drought plagued much of the corn crop in the Midwest, farmers may also be finding more corn with mycotoxins present. “Corn kernels can be predisposed to mycotoxins,” Luebbe explained. “Fortunately, ruminants are the most tolerant of these mycotoxins, so if the grain is below a certain test weight, and mycotoxins are present, the grain can be funneled to the beef industry,” he said.
For more information about low test weight corn, Luebbe can be reached at 308-632-1397, or by email at: firstname.lastname@example.org.