Forage for Knowledge

Grass growth is now ahead of demand

Grass growth is increasing and, if not managed, average covers will rise along with entry covers.

As entry covers rise, residuals can become a casualty of too much grass. I have seen this over the last couple of weeks.

On top of falling behind the wedge, grass dry matter is also high. If we over allocate, poor utilisation becomes more likely.

Once grass is leading or controlling decisions, systems feel complicated. It doesn’t need to be.

High covers are already affecting utilisation

Average covers of 2,600 kg DM/ha or more are now being seen, even where silage has been taken. This means entry covers are well above target.

When this happens, utilisation suffers, and utilisation is a profit driver. Poor utilisation will be paid for later through lower grass quality and reduced available yield.

Late heading perennials head in the first two weeks of June, and poor grazing management now often shows up then as poorer quality, slower growth and rejection.

Surplus grass can be corrected by baling, pre-mowing or post-mowing, but this is all costly in a year where profit margins are being squeezed.

Good grazing management helps protect profit if milk prices drop. Poor management quickly becomes expensive.

Start with a simple calculation

One way to get control is to start with a simple calculation, then check and fine tune it.

Those on lighter land should be more cautious in the current dry conditions. Assess soil moisture and consider how long the current covers will last.

The BBC long-range forecast is suggesting continued dry weather for a couple of weeks, followed by a shift to cooler and wetter conditions before mid-May.

If this feels likely, the approach below should work. If not, you may need to remove the top of the wedge, but less aggressively.

You can also use historic growth data to guide decisions. Look at your growth data from last spring, which was also dry, or refer to the 2025 growth curve on Forage for Knowledge to see how growth rates changed.

Using growth and demand to set a cutting target

I was on a farm earlier in the week with a high average cover, growth of 72 kg DM/ha/day, demand of 54 kg DM/ha/day and very poor residuals.

The calculation is straightforward:

• Demand is 54
• Growth is 72
• Demand as a percentage of growth is 75%

This means planning to cut the top 25% of the grazing platform as silage as soon as you can. Cutting early allows regrowth to start quickly and gives more options.

This calculation usually removes paddocks above 2,800 kg DM/ha.

Fine-tune the plan

Once this guide is set, it needs refining.

Ask the following questions:

• What is your total cow demand
• How many hectares per day are needed to meet this
• How many days will it take to get around the 75% that isn’t cut

Then consider regrowth:

• Will the cut area have regrown enough to be ready to graze by the time the uncut area has been grazed
• On the cut ground, grazing should restart at around 2,500 kg DM/ha, plus or minus 50

Check how your post-grazed paddocks are performing. Growth will be slower in the first week after cutting, then accelerate as leaf area develops.

This gives a good indication of post-cut growth rates.

If the system feels tight, try the calculation using 20% cut rather than 25%.

Use growth to your advantage

At this time of year, growth rates are rising and are likely to continue increasing for the next month.

Unless soil moisture becomes limiting, grass supply will keep building.

Run your numbers. Use growth to your advantage, rather than letting it drive decisions for you.