Farmers should not be tempted to cut grass silage too early this month unless there is a very good reason to do so, warns Nickerson forage product manager Simon Broddle, having noticed many contractors already busy forage harvesting.

“Grass silage made during May will produce highly palatable leafy silage that will be high in energy but low in fibre,” Mr Broddle explains. “While this will be ideal for feeding with wholecrop, it could be a problem if it is to be fed with maize, as this produces silage with a similar high energy, low fibre profile.

“The aim is to get a balance of forages in the winter ration which complement each other and do not upset the rumen function of the cow, or require bulk fillers like straw to be added to them.

“Another reason to delay was the combination of hot days and cold nights, which halted grass growth and the uptake of nutrients. As a result, nitrate levels within the plants could be high and this would compromise fermentation in the clamp.”

Yield penalty

Harvesting grass early will also reduce yield and cost more per hectare to harvest.

“With the significant rainfall we have had recently, swards shut up for silage could double in yield during May.

“For example, fields of Nickerson’s Red Circle, which consists of late perennials with similar heading dates, will retain their quality until the beginning of June and produce high yields of ideal material to feed with maize silage.

“There are other specific reasons for harvesting now – for example where maize is going in after a first cut, or where swards have a high Italian Ryegrass content, such as Nickerson’s Green Circle. This has a high stem to leaf ratio and therefore more fibre, ideally accompanying maize silage in the winter ration.  And farmers who are paddock grazing should consider cutting paddocks where grass growth is getting ahead of the cows, to maximise the feeding quality in the next grazing rotation.

“There is nothing wrong with harvesting early if it is a strategic decision made to produce the right type of silage to feed to meet the targets for animal performance next winter,” concludes Mr Broddle. “But don’t rush out and do it because the sun is shining and your neighbour has done his. It may pay to wait.”