When you pull into Bomaz Farms in Hammond, Wis., during silage season, what stands out isn’t just the chopper or the trucks. It’s what’s still standing in the field.
Corn stalks stand noticeably higher than what many producers are used to seeing after harvest. It’s a visual cue something different is happening in how the crop is being harvested. What’s left behind is just as intentional as what’s taken, all aimed at producing higher-quality feed.
A Hands-On Forage Program
Bomaz Farms sits about 15 miles east of the Minnesota border and is run by the Zwald family, who milk roughly 1,500 cows.
“We strive for high-quality cows that produce high-quality milk and components,” says Tom Zwald, one of the farm’s owners. “That all starts with what we put in front of them — because good cows are built on good feed.”
Zwald returned to the farm in 2012 after earning a degree in agronomy from the University of Wisconsin–Madison. While he remains involved with the cows, he takes the lead on the forage side of the operation, including cropping decisions, forage quality and equipment management.
Currently, the farm raises roughly 1,800 acres of corn and about 1,000 acres of alfalfa each year, all destined for the feedbunk.
“We do all of our own planting and harvesting,” Zwald says. “We hire the manure application, but all of the forages are completely done in house.”
Focused on Feed Value
Bomaz has cycled through several corn silage strategies over the years, including an early adoption of BMR hybrids in the 1990s and another run with them around 2016–17. After those trials, the family shifted back toward conventional genetics that better match their goals for both performance in the field and performance in the parlor.
Today, the selection process starts with how well a hybrid translates into milk.
“The biggest thing we focus on is the quality,” Zwald says. “We’re trying to maximize the amount of milk we can get from the cows.”
That means looking past traits that help grain travel around the world and instead dialing in on how that grain feeds a high-producing herd.
“Corn has been bred to make as hard of an endosperm as possible so it can export well,” he says. “When we’re in the dairy world, that’s not necessarily what we want.”
Rather than chasing yield alone, Bomaz is focused on getting more milk from every ton of forage. Genetics are only part of the equation, paired with management decisions like chop height, kernel processing and harvest timing. Together, those choices are aimed at improving the feed value in every load that comes off the field.
Moisture Still Comes First
At harvest, Zwald still points to one factor that comes before all others — moisture.
“Moisture really drives the fermentation process in silage, so getting that right window is critical,” he says. “If I miss on moisture, that can set the whole year back. That’s not a situation you want to be in.”
Once the moisture box is checked, then Zwald starts looking at the next lever he can pull: chop height.
“When I’m out sampling, I like to sample about where I think I’m going to be chopping at that year for height.”
This approach ties moisture and chop height together, instead of treating them as two separate decisions. And it’s a management decision the farm has adjusted gradually over time.
A Cut Above the Rest
Chop height on the farm didn’t go from “normal” to more than 20" in a single season. It was a slow build.
“We used to cut all of our fields at 8",” Zwald says. “Then we started thinking we could raise the bar a little. As we did, we kept seeing the feed and quality we were looking for.”
Rather than making a full switch at once, Bomaz treated chop height as an ongoing adjustment. Each year, they cut a little higher and paid close attention to how it showed up in the feed and in cow performance.
“When we first looked at higher-cut chopping, we actually sent in some samples at 6", 12" and 18", just to verify what we were doing was lining up with our goals for our feed,” Zwald says.
Those side-by-side samples gave Zwald and his nutritionist a better picture of what they were gaining — and what they were giving up — every time they raised the head. The results broke down to:
Find the Balance
As chop height increased, so did the trade-off between tonnage and feed quality. Zwald estimates that with higher cuts, the farm is leaving a meaningful amount of plant material in the field.
“I’m probably leaving a ton and a half out there of material,” he says.
But what goes into the bunker is more nutrient dense, especially when it comes to starch concentration.
“We’ve noticed that we’ve gained percentage points in starch,” Zwald says. “We’re still harvesting the same amount of grain off the cob, but we’re leaving more plant material in the field when we raise the cut.”
By removing more of the lower, less digestible portion of the plant, the harvested feed becomes more concentrated.
“If we increase the cutting height of silage during harvest, we are going to leave more of the more fibrous and less digestible part of the stalk in the field and we are going to increase the proportion of leaf and grain within the remaining silage that we harvest,” says Cole Diepersloot, Vita Plus forage specialist and dairy nutritionist.
However, Diepersloot notes the challenge of raising the cutter bar is deciding whether the quality gains are worth the tons left behind.
“If you were to increase cutting height by 10 cm, which is a pretty small increase, we would be decreasing our dry matter yield by over half a metric ton per hectare,” he says. “As you can imagine, that can be significant and adds up quickly if a farm decides to harvest all their corn silage at a greater cutting height.”
Equipment Sets the Ceiling
As Bomaz pushed chop height higher, equipment limitations eventually became part of the decision-making process.
“Last year we had a phenomenal growing season going into the year,” Zwald says. “We took it to the limit of what our chopper could do.”
With the corn growing taller, Zwald raised the cutting bar as high as it could go. But at a certain point, performance issues began to show up in the machine itself.
“We found out that once we got to about 25" to 26", we started opening up gaps on the bottom of the chopper where some plates met,” Zwald says. “So, we had to tone it back down to under 26".”
That range — roughly 25" to 26" — has become the ceiling for now, balancing forage goals with machine performance.
What’s Left Behind
Chopping silage at a higher height changes more than just what goes into the bunker. It also changes what’s left on the field going into the next crop year.
“There’s a lot of stalk hanging out there,” Zwald says. “You’ve got to make sure wires underneath tractors, choppers and trucks are all up and out of the way so they don’t get caught or ripped off.”
While the stalks break down some over the winter, the residue is still noticeable in the spring, especially when preparing fields for planting.
“They’re nice and brittle normally,” Zwald says. “But there’s definitely more stalk left out there when we’re going to plant it next year. You might have to set the trash whips a little more aggressive on the planter to make sure you’re moving that out of the way.”
Manure application and field operations can require adjustments as well, particularly in heavier residue fields.
“It’s not insurmountable,” Zwald says. “But you might have to change angle or how you’re running equipment across the field.”
A Trial Worth Taking
For producers considering higher chop heights, Zwald encourages a gradual approach rather than a full-scale change.
“Try a field,” he says. “Do half high, half low, take samples and compare.”
He says it’s a low-risk way to evaluate whether the system fits the farm.
“You don’t make big changes overnight,” Zwald says. “Try it, see if it works for your system, then decide how far you want to take it.”
Diepersloot agrees, noting higher chop heights can improve forage quality, but producers need to account for the yield they’ll leave behind.
“If you’re considering raising cutting height, you need a plan,” he says. “Whether that means growing more acres or finding another way to make up for the lost tonnage, it’s not a decision you want to make in isolation.”
More Milk From Every Acre
Conditions change every season, but the goal at Bomaz Farms stays consistent: turn every acre into the most milk-producing feed possible.
“Every year is different,” Zwald says. “But I don’t think we’re going back to cutting at 8".”
Leaving nearly 2' of stubble in some fields may turn heads, but for Bomaz, it is a calculated decision. By leaving behind the least digestible portion of the plant, the farm is focused on harvesting a more nutrient-dense forage, and it is paying off in forage quality and milk production.
For Zwald, fluctuating the chop height has become another tool in the forage management toolbox. And after years of fine-tuning the practice, the results have been enough to convince him there is no reason to go back.
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