The detrimental effects of mycotoxins

Overlooking the smallest detail can have a detrimental effect on feed use efficiency and performance – something which one Gloucestershire dairy farm found out to their cost.

Rob Costello and Tom Rowe of Rowe Farm, Whittington, suddenly witnessed a drop in milk output – something that was later attributed to mycotoxins.
Our milk yields were inexplicably dropping and the cows started to scour, says Mr Costello, who milks 180 Holstein Friesian on a high-input/high-output system.
“Looking closer, we saw that dry matter intakes (DMI) had fallen by 2%. Our adviser explained that mycotoxins were the cause and that the slight moulding on the top and shoulders of the clamps was the most likely source of the problem.”

• WHAT ARE MYCOTOXINS?
Mycotoxins are a very real problem on all farms, says Jules Taylor-Pickard, global research manager for Alltech.
“Originating in fungi on crops, these poisonous compounds can be found in what appears to be high-quality feedstuffs – particularly cereal silage – and to a lesser extent bedding.”
Mould doesn’t even have to be visible for there to be mycotoxins present and, just as there are hundreds of different moulds, there are hundreds of mycotoxins. Some of the most common affecting ruminants are deoxynivalenol, zearalenone and ochratoxin.

• A NATIONAL PROBLEM
Mycotoxins can be found throughout the UK. Studies undertaken on 38 samples of UK maize and wholecrop wheat silages for harvest in 2007 showed high levels of widespread mycotoxin contamination with no specific geographical bias. In fact, more than 60% of samples registered a “high” content of mycotoxins, presenting significant productivity risks. 
To put this into perspective Johanna Fink-Gremmels from the University of Utrecht, The Netherlands, advises that “25% of an animal’s genetic potential is stolen by mycotoxins”.
The effects associated with mycotoxicosis in dairy cattle can be diverse, difficult to diagnose and include:
• Reduced feed intake
• Scouring/bloody faeces
• Reduced milk production
• Reduced fertility
• Increased somatic cell count
• Increased disease susceptibility.
Even small amounts of mycotoxins can produce a dramatic effect as Mr Costello can confirm: “The face of the clamp is small and we get across it in two days, but the problem lay on the shoulders. There’s not much mould to see. However, one mouthful and the effects are obvious”.

• MYCOTOXIN BINDERS
Mycotoxins will develop on any growing or stored feedstuff given the right conditions, so long-term strategies concentrating on farm hygiene are essential, says Dr Taylor-Pickard.
“But when you suspect a mycotoxin problem there are more immediate options. Mycotoxin adsorbents are feed additives that can prevent and treat mycotoxicosis in animals. They are called binders because they work by ‘binding’ to harmful mycotoxins, preventing them from being adsorbed.”
While reviewing his mycotoxin management strategy, which included regular cleaning of water troughs and the feed passage, Mr Costello started to incorporate a mycotoxins binder. “The results were immediate. The cows were milking better than before, they had stopped scouring and their DMI was up,” he says.
 Mycotoxin binders do vary greatly, explains Dr Taylor-Pickard. “There are inorganic binders, made, for example, from clay, and organic binders. These additives will bind efficiently to a wide range of mycotoxins, reducing mycotoxin adsorption within the animal, but without affecting vitamins and minerals.”
At Rowe Farm Mr Costello is philosophical about his learning curve in dealing with mycotoxins. “Now when we’re doing TMR everyone knows what goes in and it is timed accurately to ensure consistency throughout the diet. Just because we can no longer see visible mould on the silage we don’t stop treating for mycotoxins – we know they are present and that a proven treatment regime will mean one less thing to worry about.”