“Our weather is unpredictable, so plan in advance and be ready to make silage when good weather provides the opportunity.”

That’s the key message from Michael Garvey of the College of Agriculture, Food and Rural Enterprise (CAFRE). In its latest management notes he said: “Walking through your standing crops of grass will allow you to make an assessment of grass growth stage and dry matter.”

Garvey stressed: “Growth stage at cutting has the greatest effect on the quality of silage made. As a guide cut before there is 50% ear emergence in the sward. Each weeks delay after this requires the feeding of an extra 2kg of concentrates to achieve the same level of milk output.”

He said: “It is possible to predict when grass crops will reach 50 per cent ear emergence. For swards based on early perennials, such as Moy and Impala, cut around May 10. Swards based on mid-season varieties, such as Spelga, Magella and Napoleon, will be ready to cut around 20 May. Cut late varieties, such as Gilford, Portstewart and Navan in the first days of June. Walk your crops prior to these dates and check for ear emergence so that you can plan a cutting date.”

silage grange (Small)

A light crop of grass, cut in good weather that has been spread after cutting should be rowed within 24 hours to prevent the crop becoming too dry

Silage dry matter (DM) has a major influence on silage intake and its ability to produce milk. Garvey advised farmers should aim to cut grass and wilt it quickly to the target dry matter. He said: “If you want a 25% DM silage do not leave the cut grass to dry for longer than 24 hours.”

The dry matter of the grass before mowing will have an impact on the amount of wilting required. If your boots are wet when you walk through your standing crop the grass has a dry matter of less than 20 per cent and will benefit from:
• Mowing in dry weather
• Mowing when sunshine is forecast
• Spreading the crop evenly after mowing
• Using a conditioner on the mower

Garvey commented: “If your boots are dry the crop has a dry matter of approximately 20 per cent and will require less active wilting. A light crop of grass cut in good weather that has been spread after cutting should be rowed within 24 hours to prevent the crop becoming too dry.

“If you have doubts about the weather at cutting time use a well tested inoculant to improve the fermentation. During filling spread the grass evenly over the pit and roll continuously. If there are unavoidable stoppages, cover the pit,” he commented.

In terms of what the ideal pit should look like he said: “Shape the top surface to allow rainwater to run off. Seal the pit immediately after filling. Fold in the cover at the walls and cover with two top sheets. Use sandbags or other methods around the edge and weigh down the remainder to reduce surface waste.”