Animal nutrition expert offers advice on dealing with mycotoxins

Fungi waste product can cause numerous problems among cattle, from reduced milk yield and fertility to leg swelling

Charlie Maclaren of the National Beef Association
Charlie Maclaren of the National Beef Association

A board member from the Hexham-based National Beef Association has warned North East farmers to be wary of the dangers posed by mycotoxins.

Formed from the waste product of fungi found naturally on grasses, straw and most living plant life, these toxins are fast becoming a major talking point among the industry due to the detrimental effect they can have on stock.

Found throughout the growing season, mycotoxins are microscopic and cannot be seen in forage, so it is impossible to identify them with the naked eye.

However, animal nutrition and management expert Charlie Maclaren said there were a number of tell-tale signs that they had been consumed by cattle.

The problem is most obvious among milking dairy cows, who may consistently fail to achieve expected milk yield or suddenly stop producing as much milk as usual.

Loose dung and rapid weight loss can also be observed, with symptoms affecting newly calved cows more aggressively

Beef cows can also be affected, with the mycotoxins causing problems with calving - including stillbirths - and a number of other issues connected with the animal’s immune system.

“It is worth noting that a suckler cow’s diet is based predominately on silage, unlike the modern dairy cow, so the effects can be even more severe,” Mr Maclaren said.

Other common effects of mycotoxins include: variable feed intake, reduced fertility, scouring, acidosis-type symptoms, lethargy, poor rumen function, muscle tremors, bloody faeces and lower leg or teat swelling.

Mycotoxins can also cause generally unsettled cows and all-round poor performance without any alternative explanation.

This year Zearalenone is the most prevalent mycotoxin, being found in forages, barley and straw, and causing a range of characteristic symptoms: abortions; decreased embryo survival; infertility and mammary gland enlargement of virgin heifers; oedema and hypertrophy of the genitalia in pre-pubertal females; vaginitis; vaginal secretions; and feminisation and infertility in young males.

Until now, testing for mycotoxins has been expensive and relatively ineffective since, despite the fact that there are hundreds of different strains, farmers were asked identify the specific toxin they wanted to look for.

Now, a simple test has been created for the two most commonly found toxins - Zearalenone and Deoxynivalenol - often known as Zon and Don.

This can be completed as farmers are sampling their silage for feed value or at any other time with a pit-face sample, highlighting potential problems before animals are affected.

Another method, commonly used by dairy farmers, involves adding a mycotoxin binder to the cow’s diet at 50gms per day.

Within several days, an increase in milk and a firming of the dung will usually be observed.

Mr Maclaren added: “It is so important that we get in front of these toxins, as if you try to play catch-up you will be too late.”

For more information, Mr Maclaren can be contacted on 07711 849 474, 01644 470 206 or


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