FARMERS are being urged to pay close attention to clamp management to reduce the potential for mycotoxin contamination which poses a serious threat to animal health and performance.

Louise Clarke, South-West technical manager for Alltech, said there is potential for silage to become contaminated with several different types of mycotoxin-producing moulds, including those originating from the field, they saw particularly high levels of penicillium moulds in the 2016 silage samples they tested.

She said: “Penicillium moulds build up in the clamp if conditions aren’t carefully controlled to ensure an anaerobic environment.

“They’re associated with the production of several different types of toxins, which are known to significantly impair rumen function resulting in acidosis type symptoms, such as diarrhoea. Subsequently, production drops, most notably yield and butterfat levels.”

Dr Dave Davies, from Silage Solutions UK, said simple measures, such as improved consolidation and better sealing of the clamp can significantly help reduce the risk of in-storage moulds developing.

He advised that when rolling grass in the clamp, producers should aim to achieve a target density of 750kg of fresh matter/m3 or 220-250 kg of dry matter/m3.

“A high density can be achieved by layering the forage in the clamp in layers no thicker than 15cm and rolling each layer between loads,” said Dr Davies. “This will result in an aerobically stable silage, that shouldn’t heat up, therefore reducing the risks of mould growth and mycotoxin formation.”

Following compaction, it’s important to sheet the clamp properly to ensure an air tight seal.

He said: “I would advise using a side sheet, oxygen barrier film and top sheet. Sufficient top weight should then be applied to form a firm seal. The junction between the wall, the top sheet and the ramp, are often problem areas and require particular care.”

Miss Clarke said silage remains the cheapest option for winter feed. “However it’s critical that grass is harvested and ensiled properly, to ensure production of a high-quality feed that presents a low risk of mycotoxin contamination,” she said.

“While taking precautions at harvest will lower the opportunity for contamination with mycotoxin producing moulds, it’s always advisable to carry out a mycotoxin test once the clamp is opened.

“Preferably, a sample should be taken from the total mixed ration (TMR), to give an accurate picture of the overall mycotoxin risk.”