Beef and Dairy Cattle Nutrition

Mycotoxin Risk Holds Steady in 2025

Mon, 23 Feb 2026 19:49:10 GMT

According to the dsm-firmenich World Mycotoxin Survey , which assessed the global mycotoxin threat, 86% of North American samples tested above the recommended threshold for at least one mycotoxin. While mycotoxin levels haven’t necessarily escalated from 2024 to 2025, there was a shift in the distribution, which has some implications for cattle and swine operations.

“The 2025 results show a continued mycotoxin challenge, with contamination rates rising for both aflatoxins and zearalenone and average levels increasing across all major mycotoxins,” said Ursula Hofstetter, head of mycotoxin risk management at dsm-firmenich, in a press release.

The Major Players

Mycotoxins are toxic metabolites produced by fungi, most commonly Fusarium, Aspergillus and Claviceps species. They develop in the field and can persist through harvest and storage. Weather stress, hybrid selection and storage management all influence which toxins dominate in a given year.

The primary mycotoxins shaping North American livestock risk in 2025 were:

Deoxynivalenol (DON)
A Type B trichothecene produced by Fusarium species. Commonly found in corn and wheat. Often referred to as ‘vomitoxin’.
Zearalenone (ZEN)
Also a Fusarium toxin. Structurally estrogenic and frequently present alongside DON in corn and small grains.
Fumonisins (FUM)
Produced by Fusarium verticillioides and related species. Predominantly found in corn.
Aflatoxins (AFLA)
Produced by Aspergillus species. More common in drought- or heat-stressed corn.
Ergot alkaloids (ERGOT)
Produced by Claviceps species. Typically associated with small grains.

These toxins rarely occur in isolation. Co-contamination often shapes the reality producers see on the farm.

What Changed from 2024 to 2025

The 2025 North American mycotoxin prevalence in raw materials compared to 2024 shows the following shifts:

DON: 74% → 76%
ZEN: 73% → 78%
FUM: 46% → 55%
AFLA: 15% → 17%
ERGOT: 44% → 9%

Trichothecenes remain deeply entrenched, with DON prevalence increasing slightly. Most of this increase is a result of an increase in wheat (73% → 93%). Meanwhile, fumonisins rose meaningfully and ergots dropped sharply.

Cattle: Rumen Function, Immune Resilience and Production Losses

Cattle historically are considered somewhat more resilient to mycotoxins than monogastrics, owing to partial ruminal detoxification. However, evidence increasingly shows persistent exposure to Fusarium toxins like DON, ZEN and FUM, especially in combination, can exert significant effects on digestion, immunity and metabolic health.

When looking at global finished feed samples for ruminants:

DON was prevalent in 69% of samples and above the risk threshold in 53% of samples.
ZEN was prevalent in 73% of samples and above the risk threshold in 33% of samples.
AFLA was present in 34% of samples and above the risk threshold in 29% of samples.

Studies have demonstrated short-term exposure to Fusarium toxins, including ZEN and FUM, affects fermentation patterns and the microbial community, which in turn can reduce fiber breakdown and volatile fatty acid production — key drivers of energy supply in cattle. Even modest disruptions to the rumen microbiota can reduce feed efficiency and gain over time.

The immune system is also affected by mycotoxins. The immunosuppressive effects of common mycotoxins in ruminants have been documented , including alterations in cytokine gene expression, immunoglobulin production and macrophage function.

Further, individual toxins like AFLA have well-established effects on liver function and general metabolism in cattle. Chronic AFLA exposure has been linked to reduced appetite, lower weight gains and elevated liver enzymes, indicating compromised hepatic function that can impact production and health resilience.

These findings indicate how cattle performance and disease resistance can be eroded by the mycotoxin patterns reported in the 2025 data. Persistent DON and ZEN exposure, combined with higher FUM presence, places additional load on rumen fermentation and immune competence, potentially contributing to subclinical production drift.

Swine: Immune Disruption, Gut Barrier Injury and Performance Drag

In swine, elevated prevalence of DON, ZEN and FUM can exert systemic effects on immune function, gut integrity and reproductive physiology at both clinical and subclinical levels.

When looking at global finished feed samples for swine:

DON was present in 85% of samples and above the risk threshold in 41% of samples.
ZEN was present in 79% of samples and above the risk threshold in 19% of samples.
FUM was present in 44% of samples and above the risk threshold in 8% of samples.

Research has shown DON and FUM alter the gut epithelial barrier, impair immune defenses and increase bacterial translocation from the gut, making pigs more susceptible to infections even when properly vaccinated. In the immune tissues themselves, DON exposure has been linked to changes in the gene expression of key antimicrobial and inflammatory regulators, implying a weakened ability to respond to disease challenge at the cellular level.

ZEN adds another layer of complexity. Beyond its well-known estrogenic effects (i.e., swelling of reproductive tissues and altered estrous cycles), ZEN has been shown to suppress antibody production in porcine immune cells, reducing levels of IgM, IgG and IgA. These immunoglobulins are important for protective vaccine responses. This explains why farms employing what should be effective vaccination programs still report breakthrough disease.

Collectively, these mechanisms mean widespread DON and ZEN exposure is a disease vulnerability issue. When the gut barrier is compromised and immune cell function is suppressed, pigs are less able to defend against respiratory pathogens, enteric bacteria and systemic infections alike, and their response to vaccination may be diminished.

Mycotoxin Co-Contamination Defines 2025

The defining feature of mycotoxins in 2025 is not a single toxin spike, but co-contamination. Feeds routinely contain multiple mycotoxins at once and their effects overlap, creating steady biological pressure.

The result is rarely dramatic toxicosis, but production drift is reflected in reduced gains, narrower reproductive margins, lowered health resilience and increased performance variability.

With persistent DON, rising ZEN and higher FUM prevalence in North America, ingredient-level vigilance and close monitoring of performance trends are important. The mycotoxin burden did not spike, but it did rearrange.

Rust in the Ration: How to Combat Southern Rust’s Impact on Corn Silage

Thu, 04 Sep 2025 14:04:48 GMT

With the warm and wet conditions this season, southern rust is on the rise in Midwest corn crops. It may be time to start considering the impact that could have on corn silage and preparing to adjust rations accordingly. While southern rust is not a direct threat to herd health, it has been shown to lower the nutritional value of silage and can compromise feed quality.

Southern rust, a fast-developing fungal disease caused by Puccinia polysora, does not itself produce toxins, but it weakens the plant and provides the opportunity for other diseases to move in. These opportunists include various Furasium species, which produce mycotoxins (fumonisin and deoxynivalenol) that can be harmful in feed.

Southern Rust and Corn Silage Quality

Southern rust is known to impact corn silage quality. A study from the University of Florida showed increasing rust infestation resulted in increased dry matter and fiber fractions, but that dry matter digestibility decreased by 13%. Further, high rust silages had lower neutral detergent fiber digestibilities than medium and no rust silages. Southern rust also affected the concentrations of lactate and volatile fatty acids, causing both to decrease with increasing infestation. These results indicate decreased nutritive value.

The observed increased dry matter also reduced silo packing effectiveness. If moisture levels are too low at harvest, it is difficult to achieve adequate packing, which leads to poor fermentation and an increased risk of mold growth.

Because southern rust coverage reduces the photosynthetic area of the leaf, grain fill is often hindered, leading to a lower energy and protein content in the silage.

Southern Rust Silage Management

There are a handful of strategies producers can apply to counteract the effects of southern rust:

Adjust harvest time based on moisture content. Southern rust can cause corn to dry down faster than normal. Monitor moisture levels closely to ensure the proper fermentation of silage.
Consider a silage inoculant. Inoculants improve fermentation, and the rapid pH drop can inhibit mold and yeast growth.
Ensure good packing and storage. Pack silage well to limit oxygen exposure and prevent mold growth. Cover bunkers immediately and weigh down coverings thoroughly.

Feeding Southern Rust Silage

To counter the nutritional challenges of feeding southern rust-infected corn silage, dietary supplementation may be necessary.

Prior to inclusion, test all potentially infected silage for mycotoxins. This will allow you to determine the safety of the feed and avoid potential health issues. If mycotoxins are high, the incorporation of a mycotoxin binding agent into the ration will help reduce toxin absorption in the animal’s digestive tract. Additionally, supplementation with antioxidants, such as vitamin E and selenium, could help animals by countering oxidative stress caused by mycotoxins and supporting immune function.

If grain fill was affected and starch levels are low, you may need to incorporate an additional energy course to compensate. Further, poor grain fill could reduce the already low protein content of corn silage, and protein supplementation may be required.

When incorporating infected silage, ensure it is thoroughly mixed into the TMR to dilute potential ‘hot spots’. Inclusion levels of contaminated silage in the feed may need to be limited or removed entirely for sensitive animals, including lactating or breeding animals. Livestock should be monitored closely for symptoms of mycotoxin toxicity, such as reduced intake, weight loss, digestive issues or reproductive challenges. Be prepared to respond if issues arise.

When feeding corn silage infected with southern rust, caution is essential to protect livestock health and performance. The thoughtful use of compromised silage can help minimize risk while maintaining efficiency and animal well-being.

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All The Details: Inside John Deere’s New F8 and F9 Forage Harvesters

Fri, 06 Jun 2025 18:20:36 GMT

John Deere is rolling out two new forage harvesters for North American dairy producers and custom harvesting operations.

The brand new F8 and F9 Series feature three factory-installed operator cab options, a technology stack that will one day enable autonomous operation, and enhanced feed quality via an integrated inoculant dosing system.

How are F8 and F9 different?
The F8 Series (425PS to 645PS) is a narrow base model that takes the place of Deere’s 8000 Series forage harvester, while the F9 Series (700PS to 1020PS) replaces the 9000 Series. Within the F9 Series is the F9 1000, which is Deere’s largest forage harvest machine to date.

(Editor’s Note: “PS” stands for Pferdestärke, which is the German term for horsepower. PS to horsepower is not an apples-to-apples equal ratio. The F9 1000, for example, features 1020PS which equates to 1,006HP, according to the manufacturer.)

The F9 is available in two engine options:

John Deere 18X (no DEF required)
Liebherr V12 24L

It has five horsepower options, while the F8 comes with the JD14X engine and can be configured across six horsepower options.

The manufacturer last rolled out completely new forage harvesters in 2019.

How much will each new model cost?

The feed rolls on John Deere’s F8 and F9 forage harvesters have integrated metal detection to keep unwanted material out of your feed.

(Matthew J. Grassi)

John Deere is not sharing its pricing just yet, but the two new models are built at its Zweibrucken, Germany, factory. John Deere dealers will begin taking orders for the aggressively styled, technology-packed harvesters this fall, with final delivery in time for the 2026 forage harvesting season.

Deere representatives declined comment on what effect, if any, the still-developing U.S.and E.U. tariff situation could have on its launch plans.

Ahead of the launch, Farm Journal went to Madison, Wisc., to kick the tires and learn all about the new machines. The F8 and F9 harvesters we viewed and climbed into were the first finished production units off the factory line. Deere says several units will be field tested with U.S. customers ahead of the full fall launch.

“We’re really excited about the new cab and the technology we’ve added to these machines like central tire inflation, ground speed automation and the new kernel processing units,” says Bergen Nelson, go-to-market manager, combines and forage harvesters.

Here’s some of what we learned about the new forage harvesters:

(Matthew J. Grassi)

Cab Comforts: The same three operator cab options offered with Deere’s X and S Series combines — Select, Premium and Ultimate — are available on the F8 and F9 Series. A smoothly swiveling captain’s chair, as well as an all-new corner post display that shows real-time machine data, are among the additions. Operators who spend long hours in the cab will also appreciate integrated entertainment like SXM Radio and an optional mini fridge.

(Matthew J. Grassi )

Foundational Deere Tech Stack: Each new forage harvester in the series includes Deere’s baseline precision tech enablement stack — which consists of its G5 display, Starfire 7500 receiver and JDLink modem.

Central Tire Inflation System: A completely new feature (top left inset photo) within the G5 display allows the operator to adjust front tire PSI up or down from the cab.

John Deere Inoculant Dosing System 2.0

(Matthew J. Grassi)

Inoculant Dosing System 2.0: New on both the F8 and F9, a high-volume 85 gallon inoculant tank and integrated pump allow the user to accurately adjust silage inoculant dosage rates from the G5 display in the cab. The system is easy to pump and prime as well with the touch of a button located at the rear of the machine.

Ground Speed Automation: This cruise control-like option reads RPMs and throttles the harvester up or down based on crop conditions. For example, harvesting corn at higher moisture levels will increase power output, so the machine will automatically slow down to ensure it doesn’t plug up or do a sub-optimal job harvesting. This feature comes standard on all base models for both series and does not require a yearly subscription unlock or per-acre fee.

Pro Touch Harvest: Another new feature within the G5 display allows the operator to shift the machine from road transport mode to harvest mode in a single click. It can also be used to quickly engage AutoTrac and ground speed automation once the operator arrives at the edge of field.

This all-new XStream 305 Kernel Processing (KP) unit is built by Scherer in Sioux Falls, South Dakota.

(Matthew J. Grassi)

New Kernal Processing (KP) Units: The new harvesters feature two completely redesigned KP units, the Ultimate 250 (also made in Germany) and the Scherer XStream 305, which is made in Sioux Falls, S.D. An integrated winch and internal rail mounting system makes switching the machine from corn forage to hay forage in the field quick and simple. The number signifies each KP unit’s roll diameter width in millimeters.

“Both KPs will go in both machines and have four different roll options depending on how aggressive the dairyman wants their end feed quality to be,” says Shane Campbell, product marketing manager, forage harvesters.

(Matthew J. Grassi)

Integrated Harvest Lab 3000: This on-demand constituent sensing module pulls over 4,000 samples per second with +/- 2% accuracy, and John Deere says it can save dairy operations time and money versus collecting and sending samples to a lab. The sensor tech (available as an add-on option) enables accurate measurement and documentation of dry matter, starch, protein, neutral detergent fiber and acid detergent fiber for both harvested forage and manure. The data can be stored, organized and shared via Deere’s Operations Center. Within Operations Center, users can take geo-referenced data and build out spatial starch content — as well as moisture and protein — maps for hybrid selection and fertility management. Because if you can’t measure it, you can’t manage it.

Active Fill Control 3.0: Using sensors and cameras on the grain spout, this tech feature automatically detects the trailer or grain cart next to the forage harvester and begins filling it with a preselected fill strategy. This reduces the number of times an operator has to adjust the spout manually and also lessens fatigue and neck strain, according to Deere.

(Matthew J. Grassi)

New Operating Modes: Several of the models within the F9 Series offer what Deere is calling its “Engine Power Plus” feature — which gives a sizeable horsepower boost when the machines senses it needs a little extra chopping power to the harvesting head. There is also an ECO mode that can be toggled on when the machines don’t need the extra torque.

Ease-Of-Access: Both models have side and rear panels that easily open to grant full access to the inner workings of the machines, making the new forage harvesters much easier to service and maintain without a lift or other heavy specialized equipment. The machine is setup so techs and mechanically-minded farmers will not have to climb underneath it to perform daily maintenance.

“At the end of the day, we know it’s all about the cow, and these machines will put out quality feed,” Nelson says. “We’ll have these out at the farm shows this summer, including Farm Progress Show, World Ag Expo, World Dairy Expo and the U.S. Custom Harvesters Convention.”

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Maximizing Profit and Opportunity: Sell, Keep or Buy Open Cows?

Thu, 10 Apr 2025 19:51:32 GMT

The goal for every cow should be to produce a calf every 365 days. One of the hardest decisions at pregnancy check time is deciding what to do with open or late-bred cows.

Kansas State University veterinarian Bob Larson says cows that don’t rebreed or that calve late are often sold because they no longer fit into a producer’s management program.

When deciding which option is best for an open cow, it is important to consider multiple economic and management perspectives.

Larson explains there are two producer approaches to open cows:

Detail-oriented, tight breeding program. He says these managers “run a really good, tight ship.” These producers calve early, keep costs under control, sell all opens and even late bred cows because they don’t fit their tight management system.
Risk-takers, opportunity seekers. “The other group who are pretty economically viable are guys who will do anything,” Larson says. “They are looking for undervalued cattle to add value to them.” These producers will keep or even buy open or late bred cows with the goal to increase value and profitability.

During a recent “ Beef Cattle Institute Cattle Chat ,” Larson and his K-State colleagues Brad White and Brian Lubbers, veterinarians; Phillip Lancaster, beef cattle nutritionist; and Dustin Pendell, ag economist, discussed cull cows. The team shares these considerations when evaluating cull cows.

Reproductive factors. Lancaster says an important question to consider is if an open cow results from a reproductive biology issue or a nutrition problem. The consensus by the Beef Cattle Institute team was that determining the exact cause can be challenging and each cow requires individual assessment. White says first-calf heifers can be a challenge due to nutrition needs and the fact they’re still growing.
Economic analysis. Pendell emphasizes the importance of putting pencil to paper and calculating costs of keeping an open cow versus selling. The cull cow market tends to have seasonal value changes. For example, White says in the fall the cull cow market tends to be lower because of the large influx of open spring-calving cows.

To overcome this potential loss in value producers could retain ownership. Larson explains winter feeding costs could be up to $2 per day. If low winter-feeding options are available, retaining ownership and feeding to add weight and trying to re-breed for next-season calving could add value to the cow. The producer could then sell as a bred cow or keep.

Another option discussed was feeding the cow as a feeder. Larson explains previous research investigating the use of a growth implant and putting the cull cow on the corn diet. He says this is a good option if the cow is thin, as she will gain efficiently and could add profit to the cow compared to selling during a lower market.

Open cows can be viewed as either a loss or an opportunity, depending on a producer’s management approach.

White summarizes the cull cow strategy by saying: “Producers don’t have to make a knee-jerk reaction. It might not be the same every year, depending on feed cost and forage availability. Do the math and decide.”

Listen to the podcast .

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Get a Rare Look Inside Iowa State University's Advanced Kent Feed Mill and Grain Science Complex

Mon, 07 Oct 2024 21:28:50 GMT

Take a tour through Iowa State University’s Kent Feed Mill and Grain Science Complex, and you’ll encounter state-of-the-art technology advancing the feed industry.

“This is our thermal processing treatment. Our feed is mixed in batches and undergoes heat treatment. The high heat and extended retention time help eliminate salmonella and E.coli, improving feed quality and nutrition,” explains Lexi Lambros, a master’s student in agricultural engineering.

The facility is not a commercial feed mill, but rather a teaching facility located at the edge of Iowa State’s Ames campus.

“We aim to increase student awareness of career opportunities in the broader feed and grain industry. This project is designed to drive that,” says Dirk Maier, Director of the ISU Kent Feed Mill Grain Science Complex.

Valued at $35 million, the project began in 2015 and has since developed into a fully automated system, providing students with hands-on experience, while also being precisely placed.

In 2023, Iowa ranked as the top corn producing state in the country, churning out 2.5 billion bushels of corn. What happens with all the crop harvested, and how it’s processed, is something they take seriously at Iowa State. September marked the one-year anniversary of ISU opening the Kent Feed Mill Grain Science Complex, a state-of-the-art teaching, research and extension grain facility, which is truly one-of-a-kind.

Automation and Scale at the Facility

“When you sum it all up, we have around 3,000 input-output points. These include sensors that control gates, motors, valves, and detect temperature and vibrations,” Maier states.

The size of the feed mill is comparable to commercial operations, though it runs on a smaller scale. Instead of processing 100 tons per hour, it handles five tons per hour, mirroring industry operations to train students effectively.

Current Capacity and Expansion Plans

With a monthly processing capacity of 1,000 tons, the facility is currently processing 200 tons weekly.

“We’re getting close to achieving our goal of processing 1,000 tons per month, and we’re on the verge of reaching that capacity,” Lambros says.

Iowa’s Prime Location

Situated in central Iowa, the facility is located in one of the world’s largest food production regions.

“If Iowa were a country, it would rank as the fourth largest corn producer globally,” Maier explains.

The facility supports the industry’s demand for future employees, training students for roles in feed mills, livestock, and poultry facilities.

Hands-On Learning for the Next Generation

The facility doesn’t focus on feed formulation, but students learn how to program different rations for various animals.

“We ensure the right ingredients are in place for the correct rations, following the instructions of animal nutritionists,” Maier adds.

As part of both the College of Agriculture and Life Sciences and the College of Engineering, students get to apply classroom lessons in a practical setting at the grain complex.

A Unique Educational Opportunity

“There are few institutions offering this kind of hands-on learning in feed science and technology, particularly in management and animal nutrition,” Maier emphasizes.

For Lambros, the facility offered a personal journey. As a second-year master’s student in agricultural engineering, her interest in food science shifted her focus.

“With my engineering background, I’m passionate about food science on a large scale, and I want to contribute to feeding the future by designing and producing food products,” she says.

After earning a bachelor’s degree in chemical engineering, Lambros sought a new challenge in agriculture, which she found through this program.

Expanding Opportunities for Students Across Disciplines

The facility opens doors for students from diverse backgrounds, from those new to agriculture to those who always knew this was their path.

“This facility offers great opportunities to bring together majors like animal science, nutritional science, agribusiness, and various engineering fields—mechanical, electrical, chemical, and agricultural,” Maier says.

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