Maize silage is a valuable resource for many farmers, providing high-energy feed that supports milk production and overall herd health. However, hidden threats can silently reduce its quality and impact your bottom line. Among the most concerning are mycotoxins in maize silage. These are toxic compounds produced by certain moulds and fungi that can develop both in the field and inside the clamp.
In this article, we’ll explore where mycotoxins come from, how they affect your silage and cattle, and what practical steps you can take to manage these risks effectively.
What Are Mycotoxins in Maize Silage?
Mycotoxins are naturally occurring toxins produced by fungi growing on crops under certain conditions. In maize, these toxins develop when the crop is stressed by weather factors like drought, humidity, or pest damage. Once formed, they don’t just disappear; they persist through harvest and into the silage.
These compounds are invisible to the naked eye but can cause serious health issues in cattle, including reduced feed intake, poor digestion, immune suppression, fertility problems, and ultimately lower milk yields.
In-Field Mycotoxins: The First Challenge
Mycotoxin contamination often begins before harvest, right in the field. Fungi infect maize plants primarily under stress conditions such as:
- Drought
- Insect damage
- Excess moisture or humidity
- Delayed harvest
Some of the main in-field mycotoxins found in maize include:
- Fumonisins (including Fumonisin B2): Produced by Fusarium species, common in stressed crops, linked to impaired liver function and reduced fertility.
- Zearalenone: Also from Fusarium, it mimics estrogen and disrupts reproduction.
- Deoxynivalenol (DON or Vomitoxin): Causes reduced feed intake and immune suppression.
These toxins form while the maize is still growing or maturing. Importantly, they survive the ensiling process and remain present in the silage, so managing them early is critical.
In-Clamp Mycotoxins and Spoilage
After harvest, silage can develop additional problems during storage, especially when oxygen enters the clamp. This exposure allows aerobic moulds and yeasts to grow, leading to heating, dry matter loss, and the formation of new mycotoxins.
The key in-clamp mycotoxins that increase due to aerobic spoilage include:
- Mycophenolic acid: Produced by certain Penicillium and Aspergillus moulds during silage spoilage, it can depress immune function.
- Roquefortine C: Another toxin from spoilage moulds, it affects the nervous system and can reduce feed intake.
- Ochratoxin A: Sometimes found in spoiled silage, it affects kidney function.
Visible signs like mould patches, warm spots, or sour smells often indicate spoilage, but the real danger lies in these invisible toxins continuing to build up and harm cattle health.
How Mycotoxins Affect Your Herd
The presence of mycotoxins in maize silage can have far-reaching consequences for your herd’s productivity and health. Some of the key impacts include:
- Reduced feed intake: Cows can detect spoilage through smell and taste, often refusing silage that contains high toxin levels. This reduces energy intake and milk production.
- Impaired digestion: Mycotoxins disrupt rumen microbes, lowering feed efficiency and nutrient absorption.
- Lower fertility: Toxins affect reproductive hormones and overall fertility, leading to longer calving intervals and fewer calves.
- Weakened immunity: Animals exposed to mycotoxins are more vulnerable to infections and diseases, increasing veterinary costs.
Because cows often show no obvious symptoms until damage has already occurred, mycotoxins represent a “hidden” threat that is costly and difficult to reverse.
Practical Steps to Manage Mycotoxins in Maize Silage
While completely eliminating mycotoxins is impossible, you can reduce their impact by following these key practices:
1. Manage Crop Health in the Field
- Harvest maize at the optimum time to reduce stress and fungal growth.
- Control insect pests and minimise physical damage to plants.
- Use resistant maize varieties where available.
- Avoid harvesting wet crops which can encourage fungal growth.
2. Ensure Proper Harvest and Storage
- Chop silage at the right moisture content to promote good fermentation.
- Fill clamps quickly and compact tightly to limit oxygen entry.
- Cover clamps immediately with high-quality sheets and seal edges to keep air out.
3. Control Aerobic Spoilage at Feed-Out
- Minimise clamp face exposure by feeding out in thin layers.
- Use biological inoculants designed to rapidly consume oxygen and suppress moulds and yeasts.
- Monitor silage temperature and smell regularly to spot early signs of spoilage.
The Role of Biological Solutions
Recent studies highlight the benefits of using biological inoculants to manage spoilage and reduce mycotoxins. For instance, SiloSolve® FC contains patented strains that work together to rapidly remove oxygen and produce acids that inhibit harmful microbes. In a 2018 study (Gallo et al.), maize silage treated with SiloSolve® FC showed a toxin reduction of:
- Roquefortine C by 87%
- Mycophenolic acid by 81%
- Fumonisin B2 by 36%
This means better silage stability, less toxin formation, and healthier cows.
Conclusion: Stay Ahead of Mycotoxins for Better Silage and Herd Health
Mycotoxins in maize silage pose a hidden risk that can quietly erode your farm’s productivity. Understanding how these toxins develop both in the field and inside the clamp is crucial. By combining good crop management, careful storage, and targeted spoilage control, you can protect your silage quality and keep your herd performing at its best.
Ultimately, staying proactive with your silage management not only safeguards your investment but also supports your cows’ health, fertility, and milk yield, keeping your farm running strong season after season.
