Mycotoxins: Are they undermining your herd's potential?
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- 4 Feb 2025
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Fluctuations in weather conditions across the UK have correlated with high levels of mycotoxins present in maize silage, particularly that of Fusarium mycotoxins. The contamination of animal feeds and forages can negatively impact cow health and performance.
The effects can include:
- Reduced dry matter intake and milk production
- Reduced function of the immune system
- Fertility issues, ultimately reducing herd profitability
What are they?
Mycotoxins are secondary metabolites that develop either in field or in storage conditions, produced by fungi species including Aspergillus, Fusarium and Penicillium. There are over 500 different species that all vary in toxicity, identifying the level of contamination in animal feeds is important to understand the effects on your herd, as well as food safety concerns.
Fungi produce toxins as a natural survival mechanism in response to stressors, including extreme weather or insect attacks. Variation in weather conditions over the 2024 growing season has provided desirable conditions for mould growth and therefore mycotoxin proliferation, particularly that of Type B Trichothecenes produced by Fusarium species.
The 2024 Mycotoxin Survey
A survey carried out by Wynnstay and Alltech involved the mycotoxin analysis of fresh maize silage from farms across England and Wales.
Several samples were collected and analysed using the Alltech 37+ mycotoxin test which identified the differing types and concentrations present in the maize silage. The results also predicted the milk yield reduction and somatic cell count increase as a result of feeding contaminated maize silage.
What We Learned from the Survey
Results from the 2024 Survey revealed that across all samples, 100% contained 2 or more mycotoxins, with an average of 5.9 detected per sample, ranging from 2 to 13 toxins per sample. 77% of samples were classified at a moderate or higher contamination risk, indicating the abundance of mycotoxins for the 2024 harvest.
Type B Trichothecenes were the most prevalent group detected, followed by Emerging Mycotoxins and Fusaric Acid. Type B Trichothecenes were detected in 100% of samples, contributing 86% to the total population on average. The highest concentration of Type B Trichothecenes detected was 17,664 ppb (average 1605 ppb), nearly eight times the higher level of 2000 ppb. Emerging mycotoxins, produced by various fungal species, were the second highest types of mycotoxins identified in 77.4% of samples, with an average of 65.3 ppb and a maximum concentration of 637 ppb. Fusaric Acid, another major mycotoxin, was detected in 71% of samples, with an average of 110.4 ppb and a high of 869 ppb, attributing 6% to the toxin population. Fumonisins, particularly Fumonisin B1, occurred in nearly 70% of samples, averaging 16.8 ppb, with a maximum of 95 ppb. Type A Trichothecenes, including T-2 Toxin, were present in 22.6% of samples at low levels, an average of 3.6 ppb. No Aflatoxin contamination was detected in the survey, as UK-grown maize is produced in a climate unsuitable for aflatoxin B1 production, which typically thrives in tropical climates.
The prevalence of Fusarium-produced mycotoxins at a significant 95% of the total population indicates the challenges for feeding maize silage to cattle this year. The route cause for the high Fusarium prevalence in the 2024 maize growing season could be attributed to various biological and environmental factors including high moisture levels during flowering, warm and humid conditions, crop genetic susceptibility, or delayed harvest, which may have all been observed in this crop.
Risk Equivalent Quantity (REQ) refers to the toxicological risk of multiple mycotoxin exposure within a sample, averaging 164.9 in the UK wide survey for dairy cattle, above the higher contamination threshold of 150. The greatest REQ calculated was 1454, nearly ten times the upper limit. Potential milk yield reduction, as a result of contamination, averaged -0.38l/cow/day, with a 54.78% increase in somatic cell count, highlighting the direct influence of mycotoxins on yield and milk quality, and significantly reducing farm profitability.
What impact will the Mycotoxin challenge have on Cow Health and Performance?
Mycotoxicosis (mycotoxin poisoning) can present itself through a wide range of symptoms and can therefore be difficult to detect without testing your silage. However, a few of the main symptoms and observations include:
- Reduction in feed intake - Type B Trichothecene Deoxynivalenol/DON causes irritation and inflammation in the lining of the intestinal tract, resulting in the animal feeling unwell, therefore enhancing reluctance to eat. There is also potential for cattle to associate mycotoxin-contaminated feed with a state of nausea and therefore refuse to eat or sort through the TMR.
- Reduced milk yield or daily live weight gain due to the reduction in dry matter intake and nutrient absorption.
- Poort fertility - Zearalenone mycotoxin causes hormonal imbalances which leads to irregular or difficult-to-detect heats, reducing conception rates. Aflatoxins and Ochratoxins can also cross the placenta and toxify tissue and the developing foetus, reducing blood flow and limiting foetal growth which can result in abortion.
- Loose Faeces due to fungal toxins causing an increase in intestinal lining permeability and therefore excess volume of water in the intestines.
- Reduced immune system function can occur as a result of phagocytic function and white blood cell production suppression, increasing pathogenic abundance and susceptibility to disease.
What is the financial Impact?
Do you know the potential cost implications this could be causing for your herd?
The average milk yield reduction of -0.38l/cow/day along with other associated health and fertility issues indicates the negative financial impact on profitability. To quantify this impact, using an average milk price of 43.5ppl (December 2024) and a 50g/cow/day feed rate of Mycosorb A+ at 9.3p/cow/day, the average milk price loss for a 200 cow herd over 30 days equates to a staggering £992.
Mycotoxin poisoning can be expensive to treat, so it's important to take steps to prevent it. One way to do this is to use Mycosorb, a product that can help to bind mycotoxins in the gut and prevent them from being absorbed into the bloodstream.
The cost of Mycosorb over this period to negate the impact of mycotoxins on milk production is £558, highlighting the importance of including a binder in contaminated feeds. These figures do not take into account the cost of fertility or other mycotoxin-associated health issues that occur, therefore the true cost of mycotoxin contamination is much higher!
How to identify a mycotoxin problem on your farm
Contamination can take various forms. In cases of sudden and unexplained low productivity, mycotoxins could be the issue.
- Visible mould in forage and feed – however, mycotoxins can still be present even if no mould is visible
- Sudden drops in intake
- A sudden drop in milk yield
- Loose/inconsistent muck
- Increased somatic cell counts
- Reduced reproductive performance
Enhancing Performance with Mycosorb A+
Mycosorb A+ is a broad-spectrum mycotoxin binder that starts binding within 10 minutes post-consumption. It contains modified yeast cell wall extract which possesses an extensive surface area (1g=20m2 surface area) for effective mycotoxin binding, as well as algae which increases the range of toxins that can be adsorbed. Mycosorb A+ reduces the absorption of secondary metabolites in the gastrointestinal tract, negating the damaging effects on cow health and production.
Key benefits & features of Mycosorb A+
- Superior binding capabilities with a broad adsorption profile
- Avoids interactions with other minerals and nutrients
- Stable over a wide pH range
- Rapid support within 10 minutes
- Effective at regular low levels of inclusion
- Proven by scientific research – 155 peer-reviewed published papers
Feeding Mycosorb A+:
Mycosorb A+ costs 9.3p/cow/day at a feed rate of 50g/cow/day. For herds with fewer than 150 cows, feeding Mycosorb A+ at 50g/cow/day over 14 days would be more cost-effective than paying for the £225 Alltech 37+ test. Elevated dry matter intake and milk yield after the 14 days are potential indicators of contamination in the silage.
Mycosorb A+ can be supplied as a farm pack which can be added to the mixer wagon or top dressed over the ration.
