The challenge of mycotoxins continues apace

What we now know is that problem is particularly acute here in Northern Ireland and the performance of dairy cows has been specifically impacted.

What are mycotoxins?

Mycotoxins are natural substances produced by moulds and fungi. They are invisible, tasteless and toxic.

More than 500 different mycotoxins have been identified to date, and most animal feedstuffs are likely to be contaminated to some degree.

These include grazed grass, conserved forages (silage, wholecrop, maize, straw), homegrown and bought-in feed.

Each plant can be affected by more than one fungus, and each fungus can produce more than one mycotoxin.

When multiple toxins are present, they can interact with each other, increasing the chances of synergistic effects.

This is when the combined effects of two mycotoxins (even at low levels) are greater than the individual effects of each toxin.

Thoughts were that mycotoxins were a risk if forage was dry or had visible mould. Although this is true, mycotoxins can be present on any forage, of any dry matter, with no visible mould and excellent clamp face management.

Putting the challenge in perspective

Richard Dudgeon is regional manager for Alltech in Northern Ireland.

He explained that a healthy rumen can protect cattle against low levels of mycotoxins.

Richard added: "Mycotoxin contamination can take many forms. Sometimes they appear as visual moulds or fungi or cause a change in the colour of the feed face, but they can also be totally invisible.

"These hidden thieves can increase the risks associated with numerous undiagnosed health issues and may be a factor leading to abortions, severe scours and sudden drops in milk.

“For the majority of dairy cows, the presence of any mycotoxins is more likely to manifest as a subtle problem; the cows might not be milking as well as they should, their dung might be a little loose, their variable or cell counts may have crept up, or their fertility levels may be on the decline.”

Dairy cow diets typically contain several concentrate and forage ingredients, increasing their risk of exposure to multiple mycotoxins.

Forages (both grazed and conserved), fermented feeds and by-products all represent a significant risk to cattle depending on the level of soil contamination, the forage harvest date, pit management, diet feed-out and management, the origins of the purchased feed and the on-farm feed storage conditions.

Mycotoxin sources

Mycotoxins in forages (e.g., grass, hays, silages, straw) pose the greatest threat to cattle.

A recent survey conducted by Alltech’s 37+® mycotoxin analytical services laboratory of the grass silage produced this year highlighted a significant risk due to the level of mycotoxins present.

The results of the survey revealed an average of 4.5 mycotoxins per sample, with 100% of the samples containing two mycotoxins or more.

While the number of mycotoxins present is cause for concern, the amount of each individual mycotoxin presentis even more troubling.

Penicillium mycotoxins continue to be the main mycotoxin group of concern, following the same trend seen in previous years.

Richard Dudgeon again:“The average level of Penicillium mycotoxins found in the samples was twice as high as what would normally be considered high-risk, illustrating the seriousness of the current mycotoxin challenge.

“These results show dairy farmers that mycotoxins are a real and evident threat to the health and performance of their dairy cows.

"Mycotoxins can impact an animal’s immune system, and an impaired immune system can be linked to many issues.

“For instance, immuno-compromised animals can be at higher risk of infectious or metabolic diseases, gut issues, feed intake depression, reproductive abnormalities (e.g.,cystic ovaries), irregular cycles and embryonic abnormalities.

“The presence of Penicillium mycotoxins can, therefore, impact an animal’s dry matter intake DMI, milk production, digestion, gut health, liver function and immune response.”

Managing the risk

In the event that the symptoms outlined above are verified as being the result of mycotoxin contamination, there are a number of ways to deal with the problem.

First off, mould formation should be eliminated by improving storage and management. Affected forages/feeds should not be fed and all spoiled feeds should be discarded.

And, finally, a mycotoxin binder - such as Mycosorb A+® - should be included in the diet.

The farmer experience

Mark Lewis milks 135 pedigree Holstein cows near Tandragee in Co. Armagh. His Rosevale Farm herd currently averages 12,000 litres at 4.15% butterfat and 3.25% protein.

Mark’s cows calve year-round and are milked courtesy of two robots that were installed in August 2020.

He is a recent convert to milk production, as the Lewis family had previously produced beef, with a herd of suckler cows serving asthe main driver of their business.

“When my father and uncle retired, the decision was taken to switch to dairy,” Mark explained.

“An investment in new housing facilities and two robots were at the heart of the transition to milk,”

Mark continued.“I was also keen to get into pedigree breeding from the get-go. Up to now, this investment is delivering for the business. The cows took to the robots very well. This frees me up to concentrate on the day-to-day management of the stock in a more precise manner.”

Mark quickly learned about the factors that can influence the performance of dairy cows.

“Breeding the right type of the cow for the production system on the farm is important,” he says.

“I am looking to breed cows with good udder placement and the ability to produce large volumes of high-quality milk. The type of cow is also important.”

With the cows on his farm housed year-round, Mark commits to producing high-quality silage throughout the grass-growing season. Four cuts are taken on an annual basis.

“Three cuts are destined for the silo; the fourth crop is baled,” he explained.

“This year, we hope to grow a crop of maize on the farm. Up to this point, we thought maize was too expensive to grow — but given the current circumstances in world feed and fertiliser markets, it may well turn out to be a cheap enough option.

"But all of this is dependent on the crop growing well enough.”

Mark has always been deeply committed to the production of exemplary-quality silage. Under normal circumstances, the investments he has made to help ensure the high quality of his silage would be fully reflected in the performance of his cows.

However, that all shifted at the beginning of last August.

“We had just changed from the inclusion of third-cut back to first-cut silage in the TMR fed to a batch of freshly calved cows,” Mark commented.

“Our anticipation had been that milk output would rise accordingly. But instead, the polar opposite happened. Milk volumes floored, and it became very obvious, very quickly, that the cows were not well at all.

“Fertility levels dropped; the cows looked very twitchy and started losing condition.”

In light of everything taking place, Mark sought veterinary advice.

The silages from Mark’s farm were analysed at the Alltech 37+ laboratory in Dunboyne, Co. Meath, where it soon became obvious that mycotoxins in the grass silage were at the heart of the problem.

“Analysis of the silage confirmed that the forage contained five-times the level of Penicillium mycotoxins that would normally be found in grass silage,” Mark explained.

Equipped with this data, Mark decided to take action by incorporating Mycosorb A+ into his feeding regime

“Mycosorb A+ is a binder based on a specific strain of yeast,” explained InTouch feeding specialist Aislinn Campbell, who was a recent visitor to the Lewis farm .

“It is a broad-spectrum binder that tackles mycotoxins rather than dealing with individual mycotoxins.

"As it is a yeast-based binder, it will bind more efficiently to a greater range of mycotoxins, reducing mycotoxin absorption without affecting vitamins and minerals.”

Mark Lewis again: “I had previously specified the inclusion of a mycotoxin binder at a preventative level.

"But this was not proving sufficient to deal with the scope of the contamination present in last year’s first-cut forage.

“The decision was then to taken include Mycosorb at an enhanced rate was then taken. This approach remedied the problem.”

The mycotoxins-related losses incurred by Mark Lewis over an eight month period were more than significant.

“The drop in milk output was one thing, but the impact on fertility will take years to recover from,” he explained.

“I consistently use sexed semen on the cows and heifers.

“Last autumn, I was getting around two confirmed pregnancies from every 20 straws of semen used. Normally, the conception rate to a sexed cow would be around 60% and possibly higher.”

Mark wants other producers to know that even if they are committed to producing the best silage possible, they could still be thwarted by mycotoxin contamination.

“Finding out that I had a very significant mycotoxin problem was a total shock to my system,” he admitted.

“The most alarming aspect to all of this is that I genuinely make an effort to make very high-quality silage. A top-class inoculant is consistently used on the grass, and every effort is made to implement the best-possible silage-making practises.”

The bigger picture

What took place on Mark Lewis’ is happening on farms across Northern Ireland at the present time.

The reality is that mycotoxins can affect any animal at any stage of production. Problems can be ongoing or can flare up suddenly, even on the same pit of silage. This could be the result of hitting pockets of mycotoxins in the silage clamp.

The threat of mycotoxins can never be fully eradicated, and the risk is especially great for producers in Northern Ireland right now — which makes implementing a mitigation strategy more important than ever.

But even more worrying is the fact Northern Ireland seems to be unique in throwing up mycotoxin-related problems in silages at the present time.

Alltech has sampled many silages made in other parts of Ireland.

And, yes, mycotoxin related issues have been identified. But not to the same extent as is the case in this part of the world.

It’s hard not to conclude that a systemic issue is casing this problem. It could be arising in the field or it could relate to clamp management practises.

The fact is that no one knows what the issue is and how it is arising in the first place. Is it not time that we found out?

About Alltech:

At the heart of Alltech is an entrepreneurial journey.

In the 1970s, founder, Dr. Pearse Lyons, immigrated to the United States with a dream: to sustain our planet and all things living on it. As an Irish scientist, he saw an opportunity to apply his yeast fermentation expertise to animal nutrition challenges, and his dream became a reality when he founded Alltech in 1980 with just $10,000.

Today, a global team of more than 6,000 people around the world shares this vision of sustaining and nourishing the world’s plants, animals and people.

Alltech deliver on this vision by improving plant, feed and food quality through nutrition and scientific innovation, particularly yeast-based technology.

What are mycotoxins?Putting the challenge in perspectiveMycotoxin sourcesManaging the riskThe farmer experienceThe bigger picture