Although we may not want to look back and remember the 2019 growing season as it brought all different kinds of challenges, we are still feeding the forages and with warmer weather coming we still need to be prepared for the continuous challenges that it may bring.  With the delay in 2019 planting due to wet conditions, a rainy growing season, and a late harvest due to uncooperative weather, putting up good forages came with additional challenges that were well out of our control.  As the weather starts to warm up, we could potentially see different undesirable organisms wake up and cause issues like reduced intakes, digestive upsets, and loss of production

This past winter when Ag Partners staff collected corn silage samples for the Corn Silage Benchmarking project for our Forage Club we looked at what our biggest challenges were last summer during the growing season and it largely came back to wet weather conditions which is a good environment for toxin development.  Besides testing for forage quality and fermentation products, we also tested for Vomitoxin (Deoxynivalenol – DON).

Although vomitoxin impact on dairy cattle alone is not well established, there are a few studies that have shown as association between vomitoxin and poor performance.  But what is more imperative is that it is believed that DON serves as a marker for the potential of mold growth and other types of mycotoxins to be present.

The graph below is the vomitoxin results from 136 corn silage samples taken from southeastern Minnesota and Western Wisconsin.   The results are in parts per million (ppm) and the colors are coordinated to the type of corn silage variety.  Every sample came back with a detectable amount of vomitoxin present, and every variety type was affected.  We did see small improvement in those that applied a fungicide, and those that applied a well-researched inoculant.  An inoculant will not detoxify mycotoxins but will ensure a quick fermentation to reach a low pH and ensure stable silage.

As we feed through the summer it is extremely important to manage your forage bunkers, piles, and bags well to minimize aerobic instability and prevent a change in pH.  If oxygen is present in your forages, it will initiate these undesirable organisms to grow.  This can be prevented with proper feed out rates, keeping the face clean and using a defacer to not disrupt the face and allow air in.

Below are some links to some loose feeding guidelines for toxins in your TMR.  Every cow could respond different dependent on their intake, stress level, and stage of lactation. Please consult with your Ag Partners nutritionist if you have any concerns.

Rock River Lab Mycotoxin Guidelines:

Dairyland Mycotoxin Guidelines:

By: Courtney Duxbury

Ag Partners Dairy Nutritionist