To support the November Hoard’s Dairyman webinar where the University of Illinois’ Mike Hutjens gave his annual crop quality review, let’s take a look at two unexpected outcomes of the 2024 corn harvest for silage season.
In covering feed quality annually, we dig into both nutritional and feed hygiene characteristics to fully characterize the crop and its feeding value. Excellent energy potential in feed can be unraveled by feed hygiene issues such as spoilage yeast or mycotoxins. Think of this interaction like fueling up your tractor with aged or contaminated diesel — the horsepower can’t be fully unleashed.
Disease may have been avoided
Reflecting back to July and early August, I was in fairly regular communications with plant pathologist and agronomist thought leaders. We were in the midst of a super soggy start to the growing season, and we were seeing higher plant disease in wheat. Mycotoxin levels in wheat and cereal grain were starting to give us concern about what the later corn harvest may carry. In conversations with Damon Smith in Wisconsin and Joe Lawrence in New York, we all echoed that the disease triangle conditions were setting up for disease potential. Then the water turned off, and we entered a late season drought.
In years past, wheat mycotoxin contamination has served as a beacon for the corn crop to follow. That didn’t happen this year. Smith and Lawrence both shared with me the view that disease pressure and mycotoxin potential fell off relative to our concerns earlier in the year. The current thought is that disease prevalence was held at bay as the weather component in the disease triangle fell off. This is welcome news, especially for eastern U.S. dairy producers that experienced higher disease pressure and mycotoxin contamination in the 2023 crop.
I tend to hold off until November or December to firmly assess the new corn silage and grain hygienic quality, though Rock River Laboratory mycotoxin analysis results are beginning to paint a cleaner silage picture for the new crop. The graph below highlights how mycotoxin results for Eastern and Midwestern corn silage samples seem to trend down for September and October. We’ll continue to watch these trends and report updates.
More digestible starch
Circling back to nutritional quality, the one additional unexpected outcome that I’ll preview is notably higher starch digestibility for new crop corn silage in the Midwest and Eastern regions. The graph below shows a roughly 5-unit increase in rumen in situ 7-hour starch digestibility, and there is a wider spread to results. Of note, “rumen in situ” means that corn silage samples are incubated in lactating cows’ rumens for seven hours. This approach and these results give us an outstanding estimate of rumen starch digestibility. I expect the starch in corn silage to feed better than in years past as we open up silos.
I think the trend in starch digestibility can be tied back to soil fertility. In 2024, plant-available nitrogen was likely lesser compared to prior years given the heavier rainfall early in the season coupled with roots being shallower due to the wet conditions. Bear with me moonlighting as an agronomist, but I contend lesser plant available nitrogen can equate to less crude protein in the grain, and then less protein can relate to a lighter test weight and more digestible starch.
We’ve focused on Midwest and Eastern growers here, but there are notable trends out West this year as well. Fiber digestibility looks to be trending up, but I’ll stop short of diving further into new crop silage quality. Watch the recording of the November Hoard’s Dairyman webinar with Hutjens and Hay & Forage Grower’s Mike Rankin for a more thorough corn silage quality preview. You can also look forward to more new crop silage content from my desk in the weeks to come.
