GrowthWatch: Focus turns to building grass covers for the autumn

By Teagasc’s Seán Cummins and James Fitzgerald

Over the last three months, grassland management on the Teagasc Green Acres Calf to Beef Programme farms has been focused on keeping to the general rules of summer grazing which are as follows:

• Keep the pre grazing yield close to 1,400kg DM/ha;
• Graze down to 4cm consistently;
• Keep the volume of grass available for grazing at 18-20 days ahead;
• Bale surplus grass when possible to maintain the above figures.

As we head into August, the way we manage grass needs to change slightly in order to ensure we begin to build up grass reserves on the farm to graze when growth rates slow down later in the autumn.

However, while doing this, we cannot afford to take our eye off the ball when it comes to grass quality, or livestock thrive will be compromised over the autumn period.

Making sure that you hit the above targets for summer grazing over the next seven-to-10 days will set your farm up well in terms of building up grass reserves from the right place.

Grass growth rates are well ahead of demand on most farms and – in most cases – the grazing rotation is currently more than 20 days.

[grass_growth_map from=”2020/07/22″ to=”2020/07/28″]

This means that a lot of farms will have to remove surplus grass in order to hit the summer grazing targets one last time.

It is also advisable to do this sooner rather than later, as higher rainfall levels and shorter day lengths will inevitably result in trickier ground conditions for heavy machinery as we move further into the autumn.

The same goes for any slurry, liming or reseeding jobs that are in the pipelines.

As of this week, what I expect to be the last of the surplus grass baled on the farm has been stacked in the yard.

This has helped me keep grass levels on the farm fairly well under control before I start to build up grass for the autumn.

I want to make a start on this in good time as the high amounts of rain we get here – and the relatively high stocking rate I am running – means that I am better off to start building up grass early and not bank on being able to keep cattle out grazing too late.

While grass growth rates have fluctuated over the last number of weeks, I am expecting to see better growth rates than this week’s 29kgDM/ha/day before the year is out.

The 30-month bullocks and spring lambs are currently being sold which is helping to reduce the demand for grass and build covers over the autumn. 

Growth has been slow over the last week and a growth rate of just 10kg DM/ha was recorded. This is back from 87kg DM/ha during the week previous.

With the low growth rate, the cattle have started to eat into the farm cover and it now stands at 404kg DM/ha.

However, second-cut silage ground will be coming back into the rotation this weekend and 60 of the yearling cattle will be moved off the home block; this will ease the pressure significantly.

We also plan on applying 27un/ac of nitrogen (N) on any of the grazed paddocks over the next while to help build grass cover moving into the month of August.

We have identified two of the worst-performing paddocks on the farm and these will be sprayed off later this week for reseeding in about two weeks.

We also plan on spreading approximately 40t of lime over the coming weeks and this will be applied at a rate of 2t/ac on some of worst paddocks in terms of pH.