Three-quarters of dairy farmers ‘feed contaminated rations’

Farmers need to test for mycotoxins and bacteria at the feed face of clamped forage to help avoid cattle health problems, a survey has shown.

Total mycotoxin levels were found to be at “worrying high levels” in 42% of maize silage samples and 24% of TMR samples.

Three samples were taken from 50 farms across the south-west of England, one from a TMR and two from silages that were included in the TMR, between March and April 2014.

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Silage and feed management, ration formulation, milk output and major animal diseases were also recorded at the time of sampling.

The research was carried out collaboratively between Bristol Vet School, the University of Nottingham, Duchy College, Micron Bio-Systems, Mole Valley Farmers and AB Vista and was revealed at the Dairy Show at the Bath and West Showground in Somerset.

“Severe health problems from mycotoxin-contaminated feed are rare in cattle. However contaminated feed can contribute to a range of common issues such as lower feed consumption and feed conversion, increased reproductive problems, lower health status and falling production,” said Micron Bio-Systems’ Mark Cox.

“Conditions such as sub-acute rumen acidosis can also impair the cow’s own natural mycotoxin defence system,” said Mr Cox.

Ms Liz Norton, Micron Bio-Systems technical support co-ordinator, explained why the levels were high this year.

“These [mycotoxins] are produced in the crop whilst it is still growing, prior to harvest, so it would have been influenced by the weather conditions during summer 2013.

“The reason why we’re seeing higher levels in maize and not in grass is due to the length of time the crop is left to mature.

“Grass is generally cut before the mould has a chance to infect it and produce toxins.

“Maize, on the other hand, is on the ground for several months, including during August and September, which last year was cool and wet – perfect conditions for fusarium mould proliferation.”


To start with, farmers must have the feed face tested for mycotoxins and bacteria, so they know what they’re dealing with before a drop in production is seen, said Mr Cox.

Ms Norton said there are simple steps that farmers can take to minimise the risk of contamination, including power washing out the mixer wagon, avoiding soil and slurry contamination and implementing good food hygiene.

Mycotoxins occur naturally in a variety of moulds that grow on food crops. The amount and type varies according to the environment. Temperature and humidity have an effect, as do insects, weeds and the way the crop is harvested and clamped.

“I think we just have to accept mycotoxins are going to be present in maize and cereal crops. The best approach would be to use a mycotoxin remediation product,” she added.

However, a key thing to remember is that toxins typically seen as part of the mycotoxin remediation product can’t be easily bound by clay mineral-based products, said Ms Norton.

They either require transformation to expose the binding site on the toxin or breaking into smaller substances that can then be bound to a clay binder, she added.

High risks were classified as being overall counts higher than 500ppb, and medium risk as those higher than 200ppb.