Be mindful of High Nitrates when cutting Grass early

Be mindful of High Nitrates when cutting Grass early
With ever more pressure to maximise milk from forage the temptation to take your first cut very early could be a big risk.

Why? What is at risk? High nitrate levels = poor fermentation


The very variable weather experienced this spring may have delayed nitrogen utilisation in grass plants, which can easily be seen in fresh grass analysis results. This could mean high nitrate levels in grass when it is due to be cut for silage.

Grass with high nitrates can result in poor silage fermentation and reduce cow forage intakes. Cows eating larger amounts of nitrates can also lead to an increase in early embryonic death, seen as lower conception rates.

Nitrate levels in grass increase following nitrogen applications because they are taken up by grass plants rapidly and stored within the plants until they are ready to make it into plant protein. Therefore, the time and growth rate between nitrogen application and cutting will affect levels in grass. So, a fresh grass analysis, which will not cost a lot, could be particularly valuable in the Spring to help prevent silage quality and cow performance issues.


Ideally grass should not be cut before nitrates have decreased to safe levels, below 0.10%. Between 0.15 and 0.25% nitrate N, there is some risk to silage quality, but this may be limited when sugar and dry matter levels are at optimal levels. Above 0.25% Nitrate N cutting should be delayed and another fresh grass sample should be taken after 3-5 days.

As always careful planning and analysis will ensure you do get the maximum.

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