Earlier first-cut silage buoys milk yields

Improve nutrition for dairy herds

Dairy farmers who take first-cut silage during April often  end up with better quality forage, says a specialist.

Sticking to a traditional May cutting date for making first-cut grass silage could be putting winter milk yield at risk, claims Amanda Clements, Ecosyl technical business manager at nutrition specialists Volac.

Recent seasons indicate that dairy farmers who take first-cut grass silage during April or very early May, rather than at the traditional timing of 10 May onwards, can end up with better overall silage quality, she adds.

Key factors

“We saw this in 2024 – but we’ve also seen it in previous seasons,” says Ms Clements, who believes it could be due to two key factors.

“First, with the generally mild winters we get nowadays, grass growth doesn’t seem to truly stop. So by the time mid-May comes around, swards can contain a lot of overwintered, dead or dying grass in the base.”

This thatchy material is of poor nutritional quality for milk production, says Ms Clements. But it is also likely to contain increased numbers of unwanted bacteria. These can interfere with how well the silage ferments.

“The second reason is if you set out with a target cutting date of around 10 May, but cutting becomes delayed due to contractor availability or poor weather, grass can rapidly go to head at this time of year.”

When this happens, grass becomes more stemmy and fibrous, and therefore less digestible, and its metabolisable energy (ME) might fall from 11.5 to 10.5, which could lose 5-6 litres of milk/cow/day, says Ms Clements.

”Stemmy grass is more difficult to consolidate, which can add to fermentation problems and lead to silage heating in the clamp.”

Taking a slightly earlier first-cut can reduce the chance of these problems occurring, as well as removing the poorer quality, old and overwintered grass, and stimulating fresher sward growth for the next cut.

“An early first-cut could be especially beneficial if you haven’t grazed off old grass with sheep over winter – or have an excess of overwintered growth,” says Ms Clements.

An early first-cut might not produce a lot of yield in some cases, she adds. But it paves the way for a better second cut, and farmers who follow this approach can get into a position where they already have two cuts completed by June.

Momentum

“If you’re able to maintain this momentum of taking each cut before grass turns stemmy, you stand to harvest grass that’s higher in digestibility, and therefore ME, for the rest of the season.

“Younger grass also tends to be higher in protein, and because each cut will be lighter than if leaving grass to bulk up, it should wilt faster. This means less chance of being caught out with mown grass lying in the field if it rains.”

Cutting earlier might mean you increase from taking three cuts to four or five cuts over the year. But cutting more often yielded more grass over the season, and the value of the extra yield and quality outweighed the extra contractor costs.

“If the quality of one cut does become affected by the weather, it will also represent a smaller proportion of the total amount of silage made. And by using different cutting dates to other farms in the area, it can improve contractor availability.”

Timely cutting remains particularly important during a hot summer because grass goes to head and becomes stemmy even sooner. But it is a proven additive can help to retain or even improve forage quality.

This can increase fermentation speed and preserve more dry matter and better silage ME. Feeding cows a range of silages preserved with Ecosyl in independent trials also boosted average milk yield by an extra 1.2 litres/cow/day.