The more grazing days a producer can get, the more feed cost savings can be realized. Grazing is considerably cheaper than feeding stored hay or silage, so extending grazing into the winter months can significantly reduce costs. One option that fits well in the Midwest is grazing corn stover. With over 10 million acres of corn in Iowa, stover is an abundant and often underutilized resource that can provide meaningful feed value when managed correctly.

How Much Feed is Available?

Corn stover typically provides enough forage to support one cow per acre for 30 to 60 days depending on weather and other factors. Cattle are selective grazers and will target the grain, husks, and leaves first, which are the most digestible parts of the plant. On average, each bushel of corn grain yields about 16 pounds of husk and leaf material. For example, a 200-bushel corn crop leaves behind roughly 3,200 pounds of dry matter per acre.

Nutritional Quality

•  Grain, husks, and leaves: Up to 75% total digestible nutrients (TDN)
• Stalks: Around 30–40% TDN

Because the more digestible components are consumed first, careful stocking rates and timely rotations are essential to maximize nutritional value. Once the grain, husks, and leaves are consumed, cattle need to be moved or supplemented. Weathering and trampling also reduce the quality and availability of feed. For more on this topic, check out this Grazing Corn Residue playlist on the Iowa Beef Center YouTube channel.

This Year’s Corn: Southern Rust

Across Iowa this season, many fields have dried down earlier than expected, and when walking through the field you may notice orange dust all over your clothing. The culprit: Southern Rust. How could this impact corn residue grazing? Well in short, we do not know, but here are some things that I would consider when grazing corn stover impacted by rust. While the disease itself does not produce toxins, it weakens the plant and could increase the risk of stalk rots such as Fusarium and Gibberella, which can produce harmful mycotoxins.

When grazing stover, southern rust raises a few considerations:

• Plant integrity: Infected plants may break down more quickly, shortening the window for palatable forage.
• Palatability: Rust infections have been linked to reduced intake and animal refusal.
• Digestibility: Research suggests infestations can increase fiber content and lower digestibility by up to 13%. This means stover may not provide the same feed value when impacted by rust, so supplementation may be required sooner at increased amounts.

At this point, we do not fully know the long-term implications of southern rust on residue grazing. What we do know is that careful observation and timely management will be key this fall and winter.

Final Management Considerations



• Timing: Begin grazing once fields are ready, ideally when soils are dry enough to avoid compaction.
•  Ear Drop: Monitor for ear loss. If more than 8–10 bushels per acre [BR3] are on the ground, a careful plan is needed to avoid grain overload and digestive issues. Here is a guide to help estimate losses or grain on the ground: “Profitable Corn Harvesting.”
• Duration: In most situations, corn stover can extend the grazing season by 60–90 days, making it a valuable resource during the winter feed gap.

Take-Home Message

Corn stover grazing is a very cost-effective winter feeding strategy available to Midwest cattle producers. This year, with higher disease pressure and the presence of southern rust, it’s important to be extra diligent, walk fields, monitor animal performance, and be prepared to supplement sooner if forage quality declines. With the right management, corn stover can continue to stretch feed resources, reduce costs, and provide flexibility in a challenging season.

Southern rust has become a widespread and severe problem for Iowa’s corn crop in 2025. 

This article was originally published online at https://hayandforage.com/article-5446-Pick-the-right-hay-sampling-tool.html

Most inaccuracies of hay test results can be attributed to the fact that the sample taken was not representative of the hay lot.

“Grab samples only represent the quality of about 1 square foot in the field, which doesn’t capture the natural variability across a hay lot,” Mary Drewnoski says. “Quality can vary not only from bale to bale, but also within a single bale, with outer layers often differing from the interior, especially for round bales that have been stored outside.”

Drewnoski, an extension beef specialist with the University of Nebraska, notes that using a hay probe is the only way to obtain a sample that accurately represents a lot of hay. She recommends coring at least 20 different bales, collecting samples that best represent field variation. When the 20 subsamples are combined, the cores should total about one-half pound of forage, providing a reliable sample for testing.

Hay probes differ

Available hay probes differ in design, ease of use, and durability. Drewnoski suggests hay probe buyers consider the following features before making a purchase decision.

Length of the probe: Select a probe 14 to 24 inches long so it will reach well into the bale and sample all layers. Shorter probes risk under-sampling the bale’s interior.

Diameter of the tube: A tube diameter of 3/8 to 5/8 inches works well, according to Drewnoski. Smaller tubes don’t collect enough material, while larger ones can be difficult to push into dense bales.

Cutting edge design: Look for a sharp, hardened, or serrated tip. Blunt or dull edges compress or shred hay, skewing results toward leafy portions. Probes with replaceable tips or ones that can be sharpened are best for long-term use.

Sample collection system: A collection canister or side window makes it easier to empty cores into a sample bag. Avoid probes that require emptying out material each time you probe — they slow the process and may lead to under sampling when fatigue sets in.

Power source: For sampling one lot, hand-driven probes may be adequate. Hand-driven probes are simple, reliable, and always ready. For multiple hay lots or frequent use, probes that attach to a heavy-duty drill can save time and energy, reducing the risk of under-sampling.

Hay probe marketers

Drewnoski offers the following list of companies that manufacture or market hay probes. She points out that this list is not exhaustive and is provided for reference only. For more extensive information on sampling hay, visit the National Forage Testing website.

AMS Hay & Forage Probe

Phone: (800) 635-7330

https://www.ams-samplers.com/hay-sampling/

Best Harvest Hay Sampler Probe

Phone: (888) 947-6226

http://www.bestharveststore.com/Hay-Probe-Samplers-c10

Colorado Hay Probe

Phone: (970) 482-2060

http://www.udyone.com/hayprobeinfo.htm

Oakfield Probe

Phone: (920) 583-4114

https://www.soilsamplers.com/collections/hay-samplers

Penn State Hay Probe

Phone: (607) 252-7540

https://dairyone.com/shop/penn-state-hay-probe-w-drill-adapter/

Sierra Hay Probe

Phone: (209) 333-3337

https://www.sierratestingservice.com/hay-probes

Star Forage Probe

Phone: (403) 471-0097

https://starqualitysamplers.com/forage-samplers/

Yankton Hay Probe (Frontier Mills)

Phone (605) 665-2441

https://frontiermills.com/

You can now follow Iowa Forage and Grassland Council on Facebook and help us promote profitable production and utilization of forages in Iowa! Follow along to:

•  Learn about forage field days & events
• Get updates about the growing season
• Hear about the latest forage research
• Promote the value of forages
• Engage in conversations about forage production, utilization, & marketing

Join I-29 Moo University and Northern Plains Forage Association on Sept. 17th for a deep dive into forage management! The webinar will be held from 7 - 8:30 PM CDT and include topics on managing weeds in hay, alfalfa quality trends & winter hardiness, and hay market insights. To learn more, visit: September Forage Webinar to Discuss Weed Control, Alfalfa Quality, Hay Market Outlook | News. 

Save the Date! A technology field day in Montgomery county will be held at the Mud Ridge Ranch near Red Oak on November 13, 2025. Real-time demonstrations will showcase cattle rotating cover crop paddocks with NoFence virtual fencing collars. A precision livestock technology trailer from South Dakota State University, packed with water monitoring technologies, animal health ear tags, and more will also be on site. For more information, reach out to Erika Lundy-Woolfolk, ISUEO Beef Specialist, at ellundy@iastate.edu.  

To learn more about how IFGC can provide financial support to forage field days, informational meetings and pasture walks, visit the IFGC website to learn more about our Education Grants Program. 

For National Soil Health Day on June 23, 2025, the Madison County Soil and Water Conservation District (SWCD) organized a Soil Health Field Day at McLaughlin Farms in rural Cumming, Iowa.

Dennis McLaughlin, a 5^th generation farmer on his family’s farm that was established in 1854, hosted the field day. The farm operation includes corn and soybeans, alfalfa, pasture, and 40 head of beef cattle (cow/calf herd). McLaughlin Farms provides many examples of management practices that incorporate the principles of soil health: minimizing disturbance, maximizing soil cover, maximizing the presence of living roots, maximizing biodiversity, and incorporating livestock.  

The field day began with approximately 50 attendees gathering in the shade on the farmstead for introductions. Everyone was encouraged to ask questions and share comments, which contributed to a rich discussion throughout the field day.

Presentations began with the Iowa Learning Farms Conservation Station. Alena Whitaker, a Water and Natural Resource Specialist with Iowa Learning Farms and Water Rocks!, gave a demonstration of the rainfall simulator. The rainfall simulator had trays representing Intense Tillage, Conservation Tillage, No-Till, Cover Crops, and Permeable Pavers (an urban/stormwater best management practice). After running the sprinkler system for a few minutes, attendees could see the difference in the amount of water runoff and infiltration from each land management example.

Next, Ruth Blomquist, the Area Soil Health Specialist for the Natural Resources Conservation Service (NRCS) in southwest Iowa, gave an overview of soil health. She discussed soil aggregates and the two things that create aggregation: biotic glues from soil organisms and exudates from plant roots. She also demonstrated the slake test to show the difference in aggregate stability for the same soil type under two different management systems.

Dennis shared information about the farm operation and how the McLaughlin family is protecting their farming legacy through an Agricultural Land Easement. Erin Van Waus, Conservation Easement Director with the Iowa Natural Heritage Foundation (INHF), explained more about the process of working with McLaughlin Farms on the easement.

After the presentations at the farmstead, attendees loaded onto hayracks to tour one of the pastures protected by the Agricultural Land Easement. Dennis McLaughlin spoke about the grazing operation, including the cattle waters and electric fence used for rotational grazing. Ruth Blomquist and Hillary Olson, NRCS State Soil Health Specialist for Iowa, discussed the qualities of the soil in the pasture, and Jeff Matthias, NRCS State Grassland Specialist, helped answer questions.

After the tour of the pasture, the hayracks returned to the farmstead where the Madison County Cattlemen provided burgers and all-beef hot dogs for lunch, and conversations continued over the meal.

While many soil health field days and workshops focus on cropland, this field day provided an opportunity to explore the topic of soil health in the context of pastures and grazing management.

Madison County SWCD would like to thank the Iowa Forage and Grassland Council, Iowa Natural Heritage Foundation, and Madison County Cattlemen for their support in making this field day possible. 

Jeff Matthias answers questions during the pasture tour at the

Soil Health Field Day on June 23, 2025.

Iowa Learning Farms Conservation Station with rainfall simulator at the

Soil Health Field Day at McLaughlin Farms on June 23, 2025.