Growing Beef Newsletter
October 2025, Volume 16, Issue 4
A combine’s trash, cattlemen’s treasure: what is different in 2025?
Beth Reynolds, IBC program specialist
Cattle have the opportunity to convert a low dollar residue into a high dollar pound of beef. Various publications on both corn residue and soybean residue address how much feed is available, and tips to build a supplementation plan to meet nutrient requirements. However, every growing season is unique and the 2025 growing season resulted in a few things to keep in mind when grazing this fall.
Fungal presence
Southern rust, tar spot, and other fungal diseases thrived in 2025. Fungi are living organisms and consume various plant components to survive and grow. This ultimately has two impacts producers should consider.
First, the fungi on residue have been consuming and digesting the most digestible components of the plant, reducing the total nutrients available as the residue makes its way through the ruminant’s digestive tract. This is ultimately shown in a lower NDF digestibility and sugar content available for the cow.
Second, because fungi have already started consuming and breaking down residue in the field, and will continue to do so, the “weathering” effect is expedited. This means the more digestible plant components, like leaf and husk, are expected to break down faster.
Combined, these two factors result in corn fields that may need a supplementation program implemented earlier, and at higher nutritive levels than in other years. Typical recommendations indicate that mature cows can maintain body condition grazing corn residue, but with low quality residue as expected this year, this may not hold true. Soybean residue already has significantly lower protein and energy content compared to corn residue, and the feed program should reflect that difference.
When fungi and molds are present, mycotoxins become a topic of concern. The main fungal issues observed this growing season are not known culprits of mycotoxin production, however fungal diseases weaken the plant and can make it susceptible to other plant diseases that do produce mycotoxins. If mold presence is high on your farm and you have concerns, call your nutritionist or a laboratory to assess your operation’s risk and determine if testing for mycotoxins and altering the feed plan is warranted.
Rapid dry down
One common report of harvest 2025 is that things dried down fast. On the bright side, bin dryers will not be needed as often, but unfortunately, harvesting at drier grain conditions increases the likelihood of leaving more grain in the field. In addition to the typical, pre-grazing scout for grain piles that a cow could overeat on, a recommended practice is to calculate an estimate of beans or corn on the ground from shatter loss or equipment mishaps before grazing. Corn on the ground prior to grazing can be estimated through a simple method described in the article “Estimate corn on the ground prior to grazing cornstalks.” If excess corn is left in the field, grain overload/acidosis is the primary nutritional risk. There are strategies to adjust bred cow diets up to a higher proportion of grain or allow growing calves or fed cattle already adapted to higher starch diets to flash graze prior to bred cows.
While bean residue is not frequently grazed intentionally to provide nutritional value to the cow herd, often cows have access to both types of residue. Due to the nature of bean residue composed primarily of stems and pods, with a small proportion of leaves, the residue is high in lignin and frankly, unpalatable. However, soybeans themselves often give a nutritional boost at about 40% crude protein. Beans are also high in fat, near 20%, and excess fat in the diet greatly hinders rumen function and fiber digestion. Total intake of raw soybeans should be restricted to only a few pounds per day. A fast dry down this year suggests shatter loss on beans could be high, so fields should be scouted prior to turnout.
Weeds
In addition to the ideal growing conditions for various fungi, weeds thrived in 2025 anywhere where there was not a healthy stand of grass to outcompete. Herbicide and other methods may have effectively controlled the weed pressure in the field, but what about in waterways and field edges? Take time to scout the field prior to grazing and ensure there are no areas infested with toxic weeds. Many toxic weeds, like cocklebur are not very palatable, and if adequate palatable forage is available, issues are not likely. However, if planning to winter feed in that area or wanting to get cattle to clean up as much residue as possible, some of these weeds can cause issues later in the season. In a previous newsletter article, “Toxic pasture weeds to watch for,” ISU forage specialist Shelby Gruss talks about most of the weeds likely to be present in pastures, which would have similar expectations as field edges and waterways.
Many annual weeds, like pigweed, are considered nitrate accumulators when growing in areas with a surplus of N available. Depending on the weed presence and whole field forage availability, it is one more consideration worth noting. For many of the potential nutritional issues, providing adequate acres and forage availability for the cow to selectively graze is a simple method to mitigate risk.
The last thing I’ll mention is to check the labels of previously applied herbicides and ensure there are no grazing restrictions. These are all factors that can be managed so that livestock producers can take advantage of the tremendous grazing opportunities crop residue provides. Being aware of potential challenges unique to the growing season before grazing, allows producers to be proactive rather than reactive, and have plans in place to best utilize the forage without sacrificing animal health or performance along the way.
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