By Dr. David Davies
Senior Research Scientist at the UK’s Institute of Grassland & Environmental Research (IGER).

Despite predictions of a UK heat wave to rival that of 2006, this year’s summer was one of the wettest on record, with flash floods devastating grassland and stalling silage production. Dr. David Davies, Senior Research Scientist at the UK’s Institute of Grassland & Environmental Research (IGER) believes this growing trend for extreme and unpredictable weather, means farmers will have to change their approach to forage.

According to Dr. Davies, climate change brings a threefold challenge to silage production: “Winters in the UK have gradually got warmer, meaning higher levels of microbes survive on forage, which can lead to mould. This problem is compounded by extreme weather conditions that reduce the quality of the yield and also make it difficult to bale forage at the traditional time.

“In the UK, for instance, the hot weather in 2006 produced a low forage yield, whereas this year the problem was more to do with timing - many farmers had to hold out for the weather to improve, meaning baling occurred when grass was past its best.”

Overcoming adverse conditions

To maximise the nutritional quality of silage baled in poor conditions, Dr. Davies strongly advocates following the guidelines that have always been recommended by IGER and Dow: “It’s more critical than ever to exclude oxygen from the point of making silage, to the point of feeding.”

“We recommend wrapping silage with six layers of film, as this provides an optimum barrier to oxygen, preventing mould and yeast growth. This is particularly important when grass has been harvested late, after a poor season. Mature forage provides an especially good habitat for many of the wrong microbes to grow and survive in, and the grass is often coarser and prone to puncturing bale wrap.”

‘Stressed’ forage that has suffered the effects of extreme weather, also has a stronger propensity to develop mould, which can lead to high levels of mycotoxins. Also this year’s flooded grassland contained a lot of silt and many thousands of undesirable bacteria per gram of grass. In such cases, Dr. Davies recommends using an additive to ensure good fermentation.

Dr. Davies also stresses that wrapping should happen as soon as possible after baling - ideally within two hours - to prevent surface level aerobic processes. He also maintains that bales should be handled and stored very carefully: transported cautiously; stored in a flat, shady area not at risk from flooding; covered in netting to protect against damage from birds and wildlife.

Be Prepared to Play Safe

IGER also highlights preparation and flexibility as equally important as baling and wrapping: “There are a lot of farmers who still make silage on the second week of the season, every year, because that’s the way their fathers did it – with changing climate conditions, this attitude has to go.”

Dr. Davies suggests farmers stop trying to predict the weather and gambling for a higher yield: “This year, those farmers who made silage in April when the weather was good, fared well – whereas those who held on for a higher yield, lost out. The weather is a lottery and it now makes more financial sense to play it safe, even if this means compromising slightly on yield”.

Whilst Dr. Davies acknowledges that certain factors can inhibit forage flexibility – such as if fertiliser has been applied – he urges farmers to think flexibly and prepare to make silage at least a week earlier than usual.

“The old adage, ‘Make Hay Whilst the Sun Shines’ can definitely be applied to silage these days – provided there’s no residual fertiliser. The experiences of recent seasons demonstrate the need for farmers to follow best practice for baling and wrapping, and be prepared, flexible and ready to react quickly to take advantage of good weather”.

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