Additives a step towards better silage

Unpredictable weather means more farmers may be turning to grass silage additives in a bid to boost quality, as Sarah Trickett found out

Grass silage additives may have been marketed in the past as “magic fairy dust” used to transform even the poorest of cuts, but they should not be seen as the only solution, according to Biotal forage product manager, Nick Berni.

“Additives are not a silver bullet when it comes to producing quality grass silage; it is just one step in a chain of events to make sure you end up with a quality product. Harvesting at the right time, clamp management as well as use of additives are all important steps,” he says.

And with forage the cheapest feed out there, it makes sense to invest a little money to get a better end product. “When you can improve the quality of forage this will not only have a knock-on effect on production, but also on fertility,” he explains.

But using an additive isn’t as easy as just chucking a product on at harvesting, as wet silage requires a different product to dry silage, explains Mr Berni.

“With wet silage there are issues with preservation so you have to produce more lactic acid to lower the pH and stabilise the silage. When a rapid pH drop is achieved, it is not only beneficial for nutrient preservation, but also for a reduction in anaerobic bacteria that cause secondary fermentation and as a result palatability problems.”

However, with a high-DM silage the challenge is to make it aerobically stable, he says. “High DM silage can be particularly prone to aerobic spoilage which means it is vulnerable to a rapid growth of yeast and mould when exposed to air.”

And because the condition of grass determines what additive is used, it is important a grass analysis is conducted prior to cutting. “Doing a combination of checks prior to harvesting will not only make sure grass is harvested at its optimum it will also help determine what additive to use.”

Relying on natural fermentation to produce quality silage can be uncertain, warns Mr Berni. “Research has suggested relying on natural fermentation can be risky. Take the wine industry as an example; they use yeast to push fermentation for alcohol and it’s a similar analogy for silage.”

And research from Frank Wright Trouw Nutrition has found, on average, grass silage quality hasn’t improved in the past 10 years, says the company’s technical director John Allen.

“In 10 years, even though we have better technology and knowledge about silage making, on average the fermentation and quality hasn’t improved.”

Dr Allen believes additives do help improve grass silage quality. “There are a number of decent-quality additives that, when used correctly and at the right rate of application, do have a role in improving fermentation quality and also feeding quality.”

However, he warns that silage additives do not make up for bad silage-making techniques.

Additives are applied during the harvesting process, with most applied via a sprayer as the crop passes through the forager, explains Mr Berni. “So applying an additive isn’t any more time consuming as it is done at the point of harvesting.”

Irving Carter: Chippenham, Wiltshire

Additives are nothing new for dairy farmer Irving Carter, having used them on his grass silage for many years. However, since investing extra money in a more expensive additive, he has noticed dramatic changes in his herd of 200 milking cows.

“I’ve always used additives but, up until last year, I was just using a cheap product that wasn’t really having much effect. However, since investing more money in a better product yields have gone up 1000 litres a cow, because silage is feeding out better and we are seeing less spoilage at the feed face, too,” he says.

Grass samples are taken before cutting to determine what additive is required and this also helps make sure grass is cut at its optimum. “Last year was the best silage we ever made in not the best of years to make silage. Cows are now eating more as it is more palatable because it has conserved better and is more stable in the clamp, which has resulted in increased milk yields.

“At first I did question whether I would see any difference, but was shocked to see such a change. The increase in milk yield more than pays for the cost of the additive,” explains Mr Carter.