Feeding mycotoxin contaminated forages

Mold spores are everywhere – in the air, on your skin and on the plants we harvest for animal feed. Certain weather conditions during the growing season can promote the growth of molds.

Mycotoxins are produced by mold that is actively growing in the field and in storage. The conundrum:  Molds can be present and growing without mycotoxin formation, and mycotoxins can be present even though mold growth is not readily visible. Only testing can determine whether mycotoxins are present.

Prevention of mold growth starts in the field. The following sets the scene for the lowest chance of mycotoxin production:

• Ensure healthy growth of plants through adoption of sound agronomic practices.
• Harvest at the proper moisture content.
• Intensely exclude oxygen at ensiling; molds need oxygen to grow.
• Promote aggressive fermentation with proven inoculants to ensure rapid and extensive silage acid production; molds grow best when pH is above 4.5.
• Remove moisture before baling and apply buffered acids as a preservative.

You can’t rule out storage-derived mycotoxin contamination due to improperly stored silages. Air infiltration and secondary mold growth can be an issue. Punctured silage bags, inadequate bunker coverings and leaking upright silos all allow air infiltration.

While corn silage and grain are typically the major mycotoxin culprits, alfalfa- and grass-based silages can also be a source.  In most of the United States, it is uncommon that field-sourced mycotoxins reach concentrations that cause widespread effects in ruminants, but it can happen when nature stacks the deck. Grain, chiefly corn, and grain co-products are typically the major source.

What are your options if the cards are not in your favor and your forage is found to contain levels of mycotoxins that are causing health and performance reductions?

1. Maintain healthy rumens with proven TMR and feedbunk management processes and ration formulation. The rumen is the first-defense as a thriving microbial community can vastly reduce mycotoxin levels. Likewise, a robust immune system – supported by a low-stress environment – helps combat metabolic challenges mycotoxins can impose.
2. A solution to pollution is dilution. Dilute high mycotoxin silage with clean on-farm silages. Current forage inventories may not allow for an efficacious change in silage ratios. Have an accurate understanding of your inventories before employing this strategy.
3. Purchase of forage fiber may be required. Lower-quality “forage extenders” can be coupled with non-forage fiber sources. Make sure that any corn co-products are not a potential mycotoxin source, adding fuel to the fire.
4. Mycotoxin remediation technologies are available and do work. Do your homework. Ask for data and involve a trusted and knowledgeable advisor. Some technologies are limited in efficacy while others are more encompassing in their ability.

Work with your nutritionist to develop a plan to minimize mycotoxin risk and effectively address mycotoxin challenges.