US feed crop testing shows high mycotoxin load

By Aerin Einstein-Curtis

- Last updated on GMT

© iStock/endopack
© iStock/endopack

Related tags Wheat Mold

Mycotoxins levels are being found in samples from the US feed crop harvest and raise concerns for 2016, says expert.

Alltech released an initial report about the potential for mycotoxin load in fall (autumn) feed crops last week. It found only about 2% of the 100 samples the company tested did not have any mycotoxins present.

The information is being offered now as a reminder for farmers and feed users to be aware of mycotoxin presence, said Max Hawkins mycotoxin expert at the Kentucky based feed additives producer. The 2016 crop is expected to be large, but feed crop quality also needs to be considered, especially if more grains are stored.

“We are finishing up the 2015 crop and we know that the 2015 crop ended up with more problems and issues from a mycotoxin standpoint, [than] when it was harvested,” ​he told FeedNavigator. “Things tend to not store as well.”

The growing season started well, but in late July many regions had excess heat, humidity and moisture, he said. “We’ve seen already the plants have lots of mold infestations, [and] that is a precursor – the enemy this year is heat and moisture,” ​he added.

“All mycotoxins are produced by molds that are soil born that’s where they’re from, but there are a variety of molds,”​ said Hawkins. “As weather effects a plant, as we stress a plant, it’s more susceptible to mold infestation.”

Rain late in the growing season also means that crops may be in fields longer, which increases the possibility of mold growth, he said. “Typically years where we have a late harvest, it’s not a good year for mycotoxins and grains,”​ he added.

Wheat samples tested came from across the US, reaching as far west as Montana but not beyond the Rocky Mountain region, he said. Corn samples were more focused on the Midwest and eastern part of the country.

Mycotoxin type

The most prevalent mycotoxins found in the sampling process were type B trichothecenes and fusaric acid, which were in 83% and 92% of samples, respectively, said Alltech. About 18% of samples had levels of 6-7 different mycotoxins, 42% had 4-5 types and 35% had 2-3 varieties of mycotoxins.

Producers should pay attention to how many types of mycotoxins are present in a feed or feed ingredient as there can be a “synergistic effect”​ when multiple ones are present, which is why Alltech tests for more than 30 varieties, said Hawkins. “[There’s] no safe limit of any mycotoxin, they can all produce negative impact,”​ he added.

Type B or Deoxynivalenol (DON) sees a magnification of effect when fusaric acid is also present, he said. “We do know they magnify each other – one plus one is not two, it’s greater than two,” ​he added.

“Some of the first signs are a big impact on feed intake and gut health, and more looseness more diarrhea,” ​he said. “Those are the things that we’re looking for – anything that reduces the animal’s normal dry matter intake or normal health protocols, those are the things to watch for.”

Other symptoms that a dairy or beef herd is seeing a challenge from DON and fusaric acid mycotoxins in the feed include cattle anorexia, depression, udder edema, enlarged mammary glands, infertility, lameness, reduce milk production, skin lesions and stillbirths, reported Alltech. Mycotoxin levels found in some samples could result in a loss of 0.5 liters in milk production per day for a dairy cow.

Mitigation strategies

There are however several steps that farmers can take to minimize the negative effects of mycotoxins, and there are ways to reduce the risk of toxin levels increasing in stored grains, said Hawkins.

Producers interested in using the feed grains should test the products to establish mycotoxin levels, said Hawkins. “We can do some dilution by using less of that ingredient in the diet and by knowing the amount and number of mycotoxins it allows you to put a more complete management program in place,”​ he added.

“A dairyman’s got to feed what he has,” ​he said. “So you have to figure out how to do that.”

For producers looking to add wheat to their ration, especially for swine, it is important to watch for amounts of DON and zearalenone, said Hawkins. The price may make it an attractive option, but it will be important to know what the mycotoxin levels are.  

“In the upper plains, what they’re seeing this year with mycotoxins in spring wheat is like what we saw in winter wheat last year – the millers don’t want to buy it to make flour,”​ he said.

Additionally, groups including farmers, co-ops and grain storage facilities need to do a better job of watching stored grains, he said. “I understand that grain producers are trying to monitor cost, but a lot of times the grain doesn’t get dried enough,”​ he added.

Although tested grain may have reached 14.5% or 14% moisture levels, producers need to ensure that the samples offer a complete picture of the grain load, he said. “You’re likely at 12% with some and 17-18% with other grain, and [anything] over 14% that is where you get into problems – we need to make sure that the samples are representative,”​ he added.

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