‘Maize silage slump’ risk when opening clamps early

Farmers forced to open maize silage clamps earlier than expected this year are being warned to keep a close eye on livestock.

A challenging season for grass growth has seen more farmers than usual feeding maize silage straight after harvest due to tight forage stocks. But doing so can lead to rumen problems, say animal health experts.

When maize silage is fed too early, inadequate fermentation time can affect rumen balance and digestion. This can lead to a maize silage slump for the animal, says Mole Valley Farmers nutritionist Kerensa Hawkey.

This can result in decreased milk production, inability to reach production targets, reduced feed intakes and loose dung, says Dr Hawkey.

New crops should be in the clamp for at least a month – and ideally not be opened until the new year.

Quality issues

“The longer the crop is in the clamp, the higher starch degradability you’ll get, leading to higher levels of fermentable carbohydrates (starch) to be utilised by the rumen in production of volatile fatty acids.

“When there is low starch degradability, there is reduced fermentable carbohydrates (starch) and increased bypass starch.

Fresh new crop maize is often high in fermentable sugars, this can lead to acidic conditions in the rumen and can contribute to sub-acute ruminal acidosis (SARA).

“The switch between old crop and new crop can put the rumen under a lot of pressure, which can result in reduced rumen function,” says Dr Hawkey, who advises farmers to introduce new crop into the ration gradually where possible.

Test silage

“Look carefully at the ration to ensure the energy and protein are balanced well, with enough total fermentable carbohydrates.

“Testing new crop silage for dry matter and nutrient composition is vital to ensure ration is supplying what you think it is.”

Additional sources may be required to balance energy within the rumen, says Dr Hawkey. Feeding yeasts such as X1-LIVE can help support the rumen bugs and improve fibre digestion.

“Yeast helps to enhance digestibility and stabilise rumen pH when transitioning onto new crop maize.

“I’d also recommend farmers consider a mycotoxin binder such as Rumi-TOX as an insurance policy in case of a mycotoxin challenge,” she adds.

As maize silage can represent a major part of the ration, understanding the degradation of maize silage is vital. Adjusting the diet accordingly using precision nutrition can increase milk production by around 1.5 litres per cow per day.

“Always monitor silage regularly and make gradual ration changes when changing silage clamps,” says Dr Hawkey.

Rumen activity warning signs

• Drop in milk yield or milk quality

• Reduced cudding, The target should be for 60 to 70% of cows to be cudding at any one time, with a cudding rate of about 60 to 70 chews per cud

• Reduced rumen fill. Check the ‘hunger triangle’ on the left of the cow. If it’s hollow or full, it indicates if cows are being adequately fed

• Change in dung consistency. Dung or slurry which is too thick or thin could indicate a rumen imbalance. So too can slime.

Reprieve for maize seed treatments

Emergency authorisations have been granted for three seed treatments for the 2024 growing season.

It follows a submission from the Maize Growers Association which argued that the seed treatments were critical for the industry. The move means growers can plan for the coming season in the confidence that drilled seed will be protected.

The three seed treatments involved are bird repellent Korit, fungicide Redigo M and wireworm product Force ST. Their use as seed treatments in imported maize seed would have been illegal at the end of 2023 had the authorisation not been granted.

MGA agronomist Jon Myhill said: “We were able to successfully convince policy makers of the importance of maize production to the livestock, dairy and biogas industries, and we can look forward to a vibrant maize growing industry for years to come.”