During a Manitowoc County (Wisconsin) forage council meeting several years ago, I was invited to come out and talk about forage management strategies. Inevitably, we got into seed genetics discussions, but this time around, we were talking about kernel processing. A custom harvester asked if there were any research studies evaluating seed genetics’ impact on corn kernel processing for silage. This question spun up quite a peer group discussion among our group as the experienced harvester described his experiences. In his view, seed genetics and hybrid clearly impacted kernel processing and diesel usage in his high-powered machine. I’ll never forget this discussion, and we’re now seeing a larger scale silage phenomenon this year that I believe trends with this gentleman's observations several years ago.

Crop quality discussions start with fiber and starch comparisons, then they transition to considering fiber digestibility. However, as we continue to better understand the impact rumen starch digestibility has on dairy performance and health, we have to account for silage rumen starch digestibility in our quality assessments. The range in corn silage 7-hour rumen starch digestibility — from as low as 60% with new crop silage to over 90% with extensively fermented silage — will impact rumen fermentation and energy, health, and performance.

With another couple of months and many more feed samples tested, the 2024 corn silage grain hardness and subsequent starch digestibility are shaping up to be notably different and regionally dependent. For example, Midwestern corn silage rumen starch digestibility is greater for the 2024 crop relative to the prior three crops at the same point time (see graph below). Eastern silage doesn’t seem to fit this trend (data not shown), which warrants a bit more future discussion. The same can be said for Western silage kernel processing scores (KPS), where the 2024 crop looks to have taken a step back relative to the prior few years. The West still leads the pack, but for some reason, the KPS trend is a bit down.

Coming back to focus on the Midwest, at the same time rumen starch digestibility is markedly up, corn silage KPS is also trending up for 2024 silages. While we can’t necessarily imply cause and effect here, I believe they’re tied together. I’ve been speculating that the softer kernels in 2024 corn equated to easier kernel processing. I’m also hearing from some grain farmers that corn test weights are down and it might be grinding easier. Again, I think these observations are all tied together. Thinking back to the custom harvester’s observations relating seed genetics to kernel processing, the growing environment also dramatically impacts corn quality. So, while there likely aren’t dramatic differences in hybrids year over year, the growing season was certainly different and looks to have affected corn grain this year.

There’s more to this story. We can dive into agronomic factors to help explain a lighter test weight, softer endosperm, and more digestible and easier-to-process grain. I believe the 2024 silage outcome we’re covering here was at least partly due to changes in plant-available nitrogen this year relative to last. The grain quality change is stemming from the soil and earlier season excessive rainfall. Stay tuned as we’ll expand on this discussion later. We’ll continue connecting agronomy to nutrition in the weeks and months ahead. But for the near term, if your farm is feeding 2024 crop, take a look at your silage rumen starch digestibility and kernel processing score. This year’s silage looks to be feeding like it’s been fermenting a bit longer for many farmers according to the trends we’re covering here.