Agronomy Advice
April 19, 2024

Walk your Fields

By: Philip Cosgrave

Throughout April and into May we’ll be focusing on optimising grass growth to meet the demands of our grazing cows so that we can maximise grazed grass in the diet.

Three people walking along a Scottish farm
Three people walking along a Scottish farm

But once we meet that magic day, our approach to managing growing grass has to change. Our priority is to ensure that we don’t lose grass quality as grass growth peaks. Whilst we still want to maximise grass growth, we need to be more reactive to what we’re seeing as we walk the grazing block.

It’s a mistake to think the more grass the better; we need to also consider quality, after all this grass feeds our cows. Too much grass can cause us problems, but it can be harnessed so that you can maintain quality at the same time as enjoying bumper grass growth. It just needs careful management.

How is too much grass a problem?

If pre-grazing grass covers get too heavy, cows’ intake will reduce as the grass is more fibrous and less digestible. This will inevitably have a negative impact on milk production. Additionally, when grass is too long, cows will struggle to graze it tightly enough, leaving higher residuals. We really need to be getting our cows to graze grass down to around 4 cm, anything higher will result in a reduction in quality in the following rotation.

Yara recommendation

There are plenty of things we can do to manage this situation but they all start with one thing: walk your grazing platform at least once a week! You need to see the situation and react accordingly because at this time of year, things can change quickly and once it’s gone too far it’s really difficult to pull back.

Once you do a grass walk, you’ll see what’s going on in each of your paddocks and can make various decisions to stay on top of your grass growth. Here are some of the things you can do to manage the surplus of grass you’re likely to see from May:

  • Use a plate meter to measure grass cover to assess how paddocks are performing.
  • Shorten your rotation length and move cows on more quickly, but this depends upon how efficient they are at grazing - you don’t want to move them on before residuals are at 4cm.
  • You might need to take paddocks out for silage. This will help you manage your grass wedge and keep pre-grazing yields below 3,000 kg/DM/ha.

AHDB recommends that ‘as soon as grass paddocks start to grow beyond 3,000kg/DM/ ha’ they should be ‘shut out and taken for silage immediately.’

Ultimately walking your grazing platform gives you the information you need to make better decisions in a more timely manner.