IMPROVE DAIRY FEED QUALITY AND HYGIENE TO COUNTERACT MYCOTOXINS

By Kevin Kouri, PMI product manager, dairy

In recent years, environmental conditions have caused crop stress, resulting in inconsistent forage quality and leading to heightened concern about mycotoxins in feedstuffs.

Part of the increased concern stems from more awareness of the challenge at hand; we have better, more accurate tools to detect mycotoxins in forages and grains than ever before. As margins have continued to shrink in some livestock sectors, byproduct feeds have become a tool to help offset these smaller margins by lowering feed costs. But, these feeds have increased the exposure risk to the animal due to a tendency of higher mycotoxin levels. We’re also paying more attention to the animal health and productivity challenges that mycotoxins can cause.

The concern is warranted. Even at low concentrations, mycotoxins in diets can:

• Reduce dry matter intake
• Lower feed efficiency
• Decrease disease resistance
• Increase reproductive issues
• Lower overall production (milk, average daily gain, days to slaughter)

Each of these issues can negatively impact economic return by reducing efficiency, reducing production or increasing the cost of veterinary services.

Higher concentrations of mycotoxins in feed can cause clinical mycotoxicosis, or disease caused by mycotoxins. Symptoms vary by toxin but can include: 

• Lesions in the liver, kidney or intestines
• Significant production losses (less milk, weight loss, reduced feed efficiency)
• Metabolic challenges or reproduction issues, ranging from delay in estrus, conception issues and potentially abortion

Healthy animals that are not immune suppressed, receive proper nutrition and are well managed and cared for tend to tolerate low levels of mycotoxins in feed. Surveying livestock operations over time, one would find periods where low levels of mycotoxins are present, but no clinical signs are being presented to farm management, nutritionist or veterinarian. However, high-producing cows and cows challenged by other issues such as lameness or heat stress are more sensitive to mycotoxins.1
 
How mycotoxin exposure affects animals

Mycotoxin levels in feedstuffs rise and fall depending on the environment. Molds that are the precursor to these toxins are present in the soils. Environmental conditions (drought, pest challenge, excess moisture) throughout the growing season can proliferate the mold, inoculate the crop during the growing phases and be present upon harvest. But, even when mycotoxins are at low levels, cows are not immune to their influences. That’s because mycotoxins have a cumulative effect over time within a herd.

Sustained mycotoxin exposure compromises cell wall integrity in the gastrointestinal (GI) tract. Reduced cell wall integrity eventually allows environmental pathogens such as salmonella, E. coli and Campylobacter to escape GI containment. That “break in the fence” means these organisms can pass through the GI tract into the bloodstream where they can cause infection, disease, or impair nutrient absorption and digestion, putting the animal in a challenge state.

These fence breaks occur with greater frequency in times of high mycotoxin exposure. But, don’t let down your guard when exposure is relatively low. Over time, the impacts of low exposure can add up. Mycotoxins can also be transient over time in the same feedstuff; periodic testing may expose varying levels that can range from harmful to manageable, and this transient pattern can create undetected risk levels.

Mycotoxins can also cause a pH swing in the rumen, negatively affecting fiber digestion and protein synthesis, which drive cows to produce milk. Swings in pH can lead to cow health challenges and lower milk production.

Take steps to confront mycotoxins

Mycotoxin impacts are complicated, so a single, simple solution likely won’t do the trick.

Here are some steps you can take to confront a mycotoxin challenge:

1. Ensure you’ve taken all steps to maintain feed quality and proper storage. These efforts will help reduce mycotoxin levels in the ration. Strategies include:
          • Harvesting forage crops at optimal moisture and maturity levels
          • Using quality bacterial inoculants and silage management practices (fill fast, pack tightly) to optimize fermentation

2. Investigate which mycotoxins are present in feedstuffs. Work with your nutritionist to submit samples to a diagnostic lab for accurate, actionable results.

3. Develop a response if you identify levels of mycotoxins that could impact animal performance. Solutions could include:
          • Diluting affected feedstuffs with clean feeds to reduce the impact of a mycotoxin challenge
          • Feeding a combination of feed additives to support forage hygiene and respond to internal damage caused by mycotoxin exposure

Choose multifactorial solutions

Responding to a mycotoxin challenge with feed additives requires a multifaceted approach.

A strategic blend of feed additives, including absorbents (flow agents), dietary yeast (prebiotics), and direct-fed microbials (probiotics) can support rumen health and dry matter intake during a mycotoxin challenge.

Different additives do different jobs. Absorbents help remove the toxins from the animal. Prebiotics feed gut microbes, and probiotics balance the overall gut population. Both support optimal microbial balance after a challenge.

Other tools such as lactic acid bacteria promoters help with volatile fatty acid profiles to help the cow’s rumen return to normal function and pH balance.

Lastly, consider increasing dietary protein, energy, minerals (Cu, Mn, Zn, Se) and vitamins (A, E, B1) to offset challenges to gut health and mitigate the impact on health and performance.

Stay the course

It may be tempting to remove absorbents, prebiotics or probiotics from the ration once a challenge has been corrected, especially when margins are tight. However, it’s impossible to know the internal damage mycotoxins have caused to the animal. You will lose the long-term benefits if you include nutritional tools for a couple weeks and then remove them. To keep cows functioning at top levels, maintain use of feed additives.

Ready to address mycotoxins more efficiently and effectively? Connect with our team.

1 B.L. Goncalves, C.H. Corassin and C.A.F. Oliveira, 2015. Mycotoxicoses in Dairy Cattle: A Review. Asian Journal of Animal and Veterinary Advances, 10: 752-760.
2 G.A. Posadas, P.R. Broadway, J.A. Thornton, J.A. Carroll, A. Lawrence, J. R. Corley, A. Thompson, J.R. Donaldson, 2017. Yeast Pro- and Paraprobiotics Have the Capability to Bind Pathogenic Bacteria Associated with Animal Disease, Translational Animal Science, 1: 60–68, https://doi.org/10.2527/tas2016.0007.
 
 
 
   
 
 

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