Webinar highlights challenge of mycotoxins in Irish silage


The 2021 POST-HARVEST surveys conducted by Alltech confirmed a high presence of mycotoxins in silages sampled in Northern Ireland, Munster and southern Leinster.

So far, forage samples across the rest of the country appear to be relatively problem-free — at least for now.

Mycotoxins are invisible to the naked eye, as are most molds that produce them. Their presence will not be reported in the standard silage analysis. Specially equipped laboratories are needed to carry out the required mycotoxin tests. Therefore, farmers may not be aware that they are feeding their dairy and cattle herds diets that can have a serious impact on overall animal health and performance.

The first sign that mycotoxins are affecting herd performance may come in the form of a significant drop in milk production levels without warning. Somatic cell count may also increase, again without any obvious discernible cause. For beef cattle, mycotoxins will cause significant production declines. Problems related to acidosis may also be apparent.

“On farms that have already identified a mycotoxin problem in their grass silages, the problem will only get worse as winter progresses,” confirmed Alltech mycotoxin specialist Dr. Max Walker. “It’s the result of oxygen in the air having access to an open face of the silo and the silage layers directly adjacent to the clamp surface.”

Dr Walker spoke at a recent silage webinar hosted by Alltech, revealing the results of the Alltech 2021 European Crop Analysis, undertaken to quantify the impact of mycotoxins in grass silage currently fed on dairy and cattle farms across Europe.

A wide selection of Irish silages have been specifically tested for the presence of mycotoxins at the Alltech 37+ Mycotoxin Testing Laboratory in Dunboyne, County Meath. The facility is unique on the island of Ireland in that it is able to test for the presence of up to 54 different mycotoxins.

“Weather conditions will have a major impact on molds that produce mycotoxins,” Dr. Walker continued. “Penicillium molds tend to

appear mainly in grass silage. They prefer relatively high

humidity levels and cooler temperatures.

“Specifically, with respect to grass, higher trash levels in the grass will predispose the resulting silages to mold infestation.

“Delays in harvesting crops will also promote mold growth in grass silages, as will the moisture content of fresh grass and the ambient temperature on the day of silage.”

According to Dr. Walker, Penicillium molds only require trace levels of oxygen in a silage claw to grow and reproduce.

“Achieving the required level of compaction at the time of ensiling is critically important when it comes to reducing the threat caused by Penicillium moulds,” explained Dr Walker.

“At the exit, it is important to

implement effective face management techniques. Any spoiled fodder should be excluded from animal feed.

Alltech 2021 European Harvest Analysis found that all grass silage analyzed contained an average of 2.9 different mycotoxins per sample.

“Multiple mycotoxins may have more impact on animals,” Dr. Walker said. “But, in most cases, that level of forage inclusion is manageable.”

Richard Dudgeon, pictured left, Alltech Regional Manager for Northern Ireland, also spoke at the webinar. He confirmed that the rumen can break down mycotoxins, but not on all occasions.

“Dairy cows that produce large volumes of milk are already under a significant level of metabolic stress,” Dudgeon explained. “As a result, they may not be able to fend off a mycotoxin challenge, as it represents an additional stressor.

“And the same principle applies to performing meat animals.”

Mr. Dudgeon then discussed the impact of the three main mycotoxins present in Irish grass silage: Penicillium toxins, deoxynivalenol (DON) and fusaric acid.

“Penicillium toxins will act to reduce milk and meat yields,” Dudgeon continued.

Rumen function will also be compromised. This can present as a form of acidosis, which can be accompanied by a significant reduction in milk fat levels.

“Fusaric acid can lead to the creation of swelling in the leg in tandem with feed refusals and general lethargy.

“DON will act to reduce dietary intake and overall production levels.

“Many molds and mycotoxins are invisible to the naked eye. They are also odorless and tasteless. But just because they can’t be seen doesn’t mean they aren’t there.

“In many cases, it is animal action that is the telltale sign that toxins are present.”

Mr. Dudgeon then discussed the properties of an effective binder against toxins.

“Myco-

toxin-binding solutions are available,” he explained. “These must be proven by independent research organizations, have a low inclusion rate and be stable over a wide range of pH values.

“Binders must also have a high affinity to absorb high and low levels of mycotoxins in complete diets.

“However, it is of crucial importance that they do not interact negatively with minerals and vitamins.”

Mycosorb A+ is a proven broad-spectrum binder from Alltech, designed to meet the challenges of high-risk mycotoxins. The product is made from yeast cell wall fractions. It interacts with mycotoxins within minutes while supporting animal immunity.

In addition, Mycosorb A+ con-

tributes to a healthy intestinal environment. The binder is stable over a wide pH range, effective at low inclusion rates, and does not negatively interact with minerals and vitamins in the diet.

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