WASHINGTON — Starch digestibility in starch-rich feeds is increasingly recognized to affect dairy and beef performance, feed conversion efficiency, and farm profitability. Dairy and beef nutritionists will readily assess corn silage, high moisture corn, or snaplage starch digestibility using rumen in situ starch digestibility measures, with a 7h rumen incubation period. Commercial feed analysis near-infrared reflectance spectroscopy (NIRS) models have sufficiently evolved to accurately measure starch digestibility as impacted by growing environment, seed genetics, plant nutrient metabolism and health, and fermentation extent.
Each of these factors is known to have an impact on starch digestibility, and in situ rumen starch digestibility NIRS models help farmers benchmark their feeds while making nutrition adjustments to improve profitability. Dry ground corn grain starch digestibility is not affected by fermentation, given none has occurred. However, shelled corn hardness and starch digestibility can be influenced by seed genetics, plant nutrient metabolism and health, and growing environment. NIRS in situ rumen starch digestibility models are also robust for dry ground corn.
Historically, yellow No. 2 corn has been assumed a commodity. Feed library values have driven diet formulation and feed purchasing decisions. Thanks to commercial feed analysis advances and more farmers testing their grain, consistency in commodity corn grain is being questioned. Meaningful deviations in nutrient content and starch digestibility have been uncovered on a case-by-case basis.
“Now, with thousands of dry corn analyses over the past three crop years to draw insight from, an impactful trend has come to light,” says John Goeser, animal nutrition, research and innovation director for Rock River Laboratory. “The 2021 and 2022 crop years’ dry ground corn is less digestible.”
Figures 1 and 2 demonstrate the population distributions for starch content and in situ rumen starch digestibility with dry corn samples analyzed by Rock River Laboratory for the Midwestern and Eastern US regions. “Notably, there is slightly less starch content in 2022 and 2021 crop years, relative to 2020 corn,” outlines Goeser. “More importantly, though, the corn grain in situ rumen starch digestibility is lagging behind, with 2022 corn around 10 percent less than 2020 corn.”
Do not assume that commercial dry ground corn is a consistent commodity. Rather, consider checking your corn quality and discuss the impact that measured corn grain quality and digestibility have, relative to feed library benchmarks. Goeser advises, “corn grain is increasingly valuable, and decreasing corn grain particle size can help offset less digestibility.”
Founded in 1976, Rock River Laboratory is a family-owned laboratory network that provides production assistance to the agricultural industry through the use of advanced diagnostic systems, progressive techniques, and research-supported analyses. Employing a team of top specialists in their respective fields, Rock River Laboratory provides accurate, cost-effective, and timely analytical results to customers worldwide, while featuring unsurpassed customer service.
–Rock River Laboratory
