Corn harvest for silage is underway for Southern growers and about to kick into high gear for many Northern dairy forage growers and farmers. As the season moves along, crop and harvest management opportunities are coming into focus.
The crop looks to be worth roughly $50 to $85 per ton this year when benchmarking against $5 to $6.50 or greater per bushel corn. The financial incentives to optimize the crop harvest timing and quality, preserve every ton possible through ensiling to feed-out, and optimize rumen starch digestibility are as strong as ever.
While the growing conditions are beyond our control, there are several key management considerations to stay on top of as your corn crop comes into the harvest window. Monitoring crop health, watching for tar spot, and managing to harvest silage with both optimal whole-plant moisture and kernel maturity are now our focal points. Make no assumptions this year — get active with your advisory team.
In line with Aaron Maassen and Bill Mahanna’s comments summarized by Abby Bauer in the Hoard’s Dairyman Intel article, “Consider this advice when using bunkers,” get out and walk your fields looking for ear and stalk disease pressure. In recent text conversations with the University of Wisconsin’s Damon Smith, he let me know that tar spot is cropping up in more and more locations. Tar spot is not a mycotoxin and health concern, but it can rapidly infect fields and kill plants quickly. The dead plants begin drying at the same rate, regardless of relative maturity, and can shorten the harvest window dramatically due to many acres drying at the same pace.
Another area to watch passed along by Damon was to ensure you and your agronomist are aware of your pre-harvest interval if you applied fungicide later in the season. Given ear and stalk rot concerns, as well as tar spot, some have applied fungicide later this year. Overall, the next couple of weeks will be telling of this disease pressure. With an extremely valuable crop standing in the field, we need to prioritize walking fields above other less impactful tasks and then begin checking moisture and kernel maturity.
Historically, we’ve used whole plant chopped corn moisture as both an indicator of kernel maturity as well as a fermentation potential factor. Missing the harvest window on the dry side cannot be an option on your farm, recognizing that drier corn silage tends to be more mature, with less digestible fiber and grain, and does not pack or ferment as well. Taken collectively, these three outcomes equate to substantial milk losses and feed stability problems. Corn silage is a great crop for consistency in the ration; however, if we miss our harvest targets, the corn silage will consistently be a yearlong headache.
To avoid silage that feeds poorly, target around 65% whole-plant moisture. Check numerous spots and from numerous fields. Take at least five to 10 stalk samples from well within the field if you are not running the chopper into the field to open fields and check moisture.
Whether you’re opening fields or taking hand cut stalk samples, break ears open and look at the kernel maturity. While moisture and kernel maturity have been correlated for decades, seed genetics and plant health are changing. Stay green genetics have contributed to kernel maturity and whole-plant moisture, a disconnect for many farmers.
In 2022, do not assume whole-plant moisture is the only harvest timing indicator for your farm. We may need to move our target moisture window according to kernel maturity, as 2021 highlighted how adequate moisture can correspond to less than ideal kernel maturity and silage starch digestibility. This cost many dairies substantially for months.
Kernel maturity matters to cows
Setting whole-plant moisture aside, one-half milkline kernel maturity is the sweet spot for balancing corn silage starch content and digestibility. The further the milkline moves, the more starch is laid down in the grain but it’s also harder and less digestible. Last year, 65% moisture looked to match up with greater than one-half-milkline kernel maturity and harder grain. This was clearly visualized in silage starch digestibility analysis. This was the subject of many articles, webinars, and conversations with nutritionists and dairy farmers, including my recent Hoard’s Dairyman webinar, “Make the most of this year’s corn silage,” where I highlighted how challenged starch digestibility was for 2021 silage relative to 2022.
The net outcome?
The 2021 silage didn’t achieve its full feeding potential until nearly spring 2022. In hindsight, we may have benefitted by beginning harvest at a bit wetter moisture level to achieve optimal energy value per ton in silage.
Here is my advice . . . stay on top of your silage corn kernel maturity this year. If 2022 shapes up in the field like 2021, consider beginning harvest slightly sooner to balance kernel maturity and whole-plant moisture.
Drawing to a close, I am expecting a variable crop in yield and quality due to growing conditions. Conditions ranging from drought to excessive rainfall have been recognized across the U.S. Hay and haylage quality has been as wide as we’ve experienced in the past five years, and silage will likely follow suit. Make an effort to squeeze the most milk out of your silage by staying attentive to impactful factors discussed here. And lastly, please be safe.