Global mycotoxin contamination report 2023:
Key findings for ruminants

The "Global Mycotoxin Contamination Report 2023" by Selko provides an in-depth multispecies analysis of mycotoxin contamination in various raw materials and animal feeds worldwide. The report, based on data collected from January 1, 2023, to December 31, 2023, includes analysis results from over 66,000 samples across 35 countries and was presented on February 18, 2024, during an online webinar. This article highlights key findings from grain byproducts, ruminant feed, and silages, shedding light on the contamination levels, prevalence, and implications for dairy farming.

The review is based on an extensive dataset, encompassing 66,280 analyses conducted across 35 countries. This dataset includes 44,680 raw material samples (67.4%) and 21,600 complete feed samples (32.6%). The mycotoxins analyzed include Aflatoxins (AFLA), Ochratoxin A (OTA), T-2/HT-2 toxin (T2HT2), Fumonisins (FUM), Deoxynivalenol (DON), and Zearalenone (ZEA).

The animal industry faces the challenge of feeding a growing human population amidst declining resources. Given the ubiquity of mycotoxins, it is crucial to understand the risks they pose to ruminant health and performance to use raw materials judiciously. Selko has developed practical mycotoxin guidance values specifically for dairy cows (Table 1.).

Ruminant feed, which includes a mix of grains, byproducts, and forages, is a critical area of focus in the report. The findings indicate significant mycotoxin contamination that can affect the health and productivity of dairy cows:

• Overall contamination: The report shows that a high percentage of ruminant feed samples were contaminated with mycotoxins exceeding the safe zone for mycotoxin concentrations (Figure 1.).
• Impact on dairy cows: Contaminated ruminant feed can lead to a condition known as "leaky gut," where the intestinal barrier is compromised, allowing toxins to enter the bloodstream. This results in systemic inflammation, reduced nutrient absorption, and overall poor performance in dairy cows.
• Key mycotoxins in ruminant feed: DON, ZEA, and FUM were the most common mycotoxins found in ruminant feed (Table 1.). These toxins can impair rumen function, reduce feed efficiency, reproduction and ultimately lower milk yield. The report emphasizes the importance of regular monitoring and the use of mycotoxin binders to mitigate these effects.

Unlike grains and protein meals, analyzing mycotoxins in silage requires special attention due to the high fiber content and pigments that can interfere with results. A specialized extraction step is necessary for accurate analysis. As shown in Table 3, the average concentrations of DON (deoxynivalenol) in silages were higher than FUM (fumonisins), which is the opposite of what is typically seen in other raw materials and finished feeds. Elevated DON levels in silages can increase its presence in total mixed rations (TMR), putting more pressure on the health and performance of dairy cows. Mycotoxins in silages result from both field contamination of crops and suboptimal silage quality. Good silage practices that ensure anaerobic conditions can help reduce mold growth and subsequent mycotoxin production. Besides DON, the levels of T2/HT2 and ZEA (zearalenone) in the tested silages can also contribute to increased toxicity in TMR.

• Contamination levels and risks: The contamination levels in silages were found to be significant, with many samples exceeding safe thresholds. High levels of ZEA and DON in silages can lead to reproductive issues and digestive disturbances in dairy cows, impacting their overall productivity and health.
• Management practices: The report highlights the importance of proper silage management practices to minimize mycotoxin contamination. This includes using high-quality forages, ensuring proper fermentation, and utilizing silage additives that can inhibit mold growth and mycotoxin production.

Table 3. Mycotoxin contamination in silages

Grain byproducts are essential components of ruminant diets due to their high nutritional value and cost-effectiveness. However, they are susceptible to mycotoxin contamination, which poses significant risks to animal health and productivity. The 2023 report reveals the following key points:

• Prevalence and types of mycotoxins: The report highlights that grain byproducts are frequently contaminated with mycotoxins such as aflatoxins (AFs), deoxynivalenol (DON), fumonisins (FUM), ochratoxin A (OTA), T-2/HT-2 toxins, and zearalenone (ZEA). Among these, DON and ZEA were the most prevalent.
• Contamination levels: The average contamination levels for DON and ZEA in grain byproducts were significantly high. This can lead to reduced feed intake, impaired immune function, and lower milk production in dairy cows.
• Regional variations: The contamination levels varied across regions, with some areas showing higher incidences due to climatic conditions favorable for mycotoxin production. For instance, regions with higher humidity and temperature were more prone to aflatoxin contamination.

The findings from the report underscore the ongoing challenge of mycotoxin contamination in dairy farming. Mycotoxins in grain byproducts, ruminant feed, and silages can severely impact the health and productivity of dairy cows, leading to economic losses for farmers. Key implications include:

• Health issues: Mycotoxin-contaminated feed can cause a range of health problems in dairy cows, including reduced feed intake, digestive disorders, immune suppression, and reproductive failures. These issues not only affect the cows' well-being but also their milk production and quality.
• Economic impact: The economic losses associated with mycotoxin contamination are substantial. Reduced milk yield, increased veterinary costs, and lower feed efficiency all contribute to the financial burden on dairy farmers.
• Need for monitoring and management: Regular monitoring of feed ingredients for mycotoxins is crucial. Implementing effective mycotoxin management strategies, such as using mycotoxin binders, enhancing feed storage conditions, and adopting good agricultural practices, can help mitigate the risks.