December 02, 2023

Test silage for dry matter before chopping

WATERTOWN, Wis. — Dairymen have the potential to harvest some good corn silage this year even though the early part of the growing season was dry.

“In drier years, we get shorter plants that have more grain relative to stover,” said John Goeser, animal nutrition, research and innovation director at Rock River Laboratory.

“So, we’re expecting pretty high starch content and higher fiber digestibility, which is going to be really good for milk per ton,” said Goeser during a webinar hosted by Hoard’s Dairyman. “It may not be the biggest yields per acre, but we could have pretty good feeding corn silage.”

“Many have experienced smoke from the wildfires in Canada and our crops rely on light intensity for photosynthesis,” he said. “So, that has likely had an impact on crops.”

If a cornfield was flooded, Goeser said, it likely had an impact on fertility since nitrogen is quite mobile with rain.

“That could mean a crop with a little bit lower crude protein,” he said.

Dairymen are going to be challenged with widespread quality.

“Not only did we have a widespread to pollination, we also had a widespread to germination,” Goeser said. “So, it will be tougher to manage for timing.”

Therefore, it is important to chop the corn based on actual dry matter.

“Do whole plant dry matter and don’t use one field as a signal,” Goeser said. “You need to sample more fields and more spots within a field to understand where your crop is at with maturity.”

Avoid harvesting silage too early, the research director said.

“Target 65% whole plant moisture on the pile,” he said. “If you have fields that are not close, you may opt to split the forage into two silos or two piles.”

It is important for dairymen to walk their fields.

“Do not do a drive-by,” Goeser said. “Spend a little more time walking fields. It will pay off.”

Since Goeser is expecting a wide harvest window, he suggests dairymen should start walking their fields 40 to 45 days after the average tassel date.

“You might not be chopping until 60 days after tasseling,” he said.

In addition to whole plant moisture, Goeser said, consider the kernel maturity and plant health.

“I’m expecting pretty good plant health,” he said.

Dairymen with cornfields that have hail damage should talk with their agronomist, Goeser said.

“If it’s destroyed, treat it like a sorghum silage and keep this feed separate,” he said.

Decisions with drought-stressed corn can be based on the ear leaf, which is the leaf adjacent to the ear.

“If it is green, let the plant go,” Goeser said. “There is a potential for nitrate toxicity, so use a forage inoculant, which is a great investment to optimize fermentation efficiency.”

Test for nitrates in drought-stressed corn before feeding the silage, the animal nutrition director said.

“Fermentation can clean up the nitrates,” he said.

Nitrates will localize in the bottom portion of the stalk.

“When you chop a little higher, you expect less yield. But with tall corn, you will increase the starch content because you’ve got more grain and less stover,” Goeser said. “You also see an increase in fiber digestibility because there is less lignin in the silage.”

By raising the cut height 10 inches, you can get another one to two pounds of milk production per cow per day, Goeser said.

“That comes from the increase in fiber digestibility and starch content,” he said.

Goeser encourages dairymen to achieve a kernel processing score of 75% to 80 %.

“It is important for fields that are more mature,” he said. “You need to do everything you can to optimize starch digestibility, so it is really important to nail down kernel processing this year.”

Goeser has seen several corn silage piles that have collapsed.

“I think it is due to higher quality fiber from healthier plants,” he said. “So, if your dairy experienced a cave-in this year, consider making your cut length a little longer.”

Martha Blum

Martha Blum

Field Editor