GrowthWatch: Ample rainfall drives grass growth

By Teagasc’s Seán Cummins and James Fitzgerald

Rainfall levels over the past week have varied greatly depending on location with rainfall being very localised in many cases.

As a result, grassland management decisions need to be made based on the rainfall levels you received on your farm.

Continue to aim for:

  • 18-21 day rotation (25 days if insufficient rain received);
  • Post grazing height of 4cm;
  • Pre grazing yield of 1,300-1,400kg DM/ha.

For the majority of the country, ample rain has been received to give a good level of grass growth over the next number of weeks. However, there are some areas that need to receive more rain in the coming days and weeks in order to maintain high growth rates.

Now is a very good time to quantify the silage reserves you have on your farm and the yield you expect to get from your second cut.

Compare this to the quantity of silage you think you will need for the winter and act accordingly if there is a deficit. The fodder budgeting tool on PastureBase Ireland is very helpful in completing this task.

The options available to you if a deficit is present include:

  • Keeping less stock for the winter through finishing cattle early or culling non-productive stock;
  • Close a proportion of your ground for a third cut of silage;
  • Spread more fertiliser now so that more surplus bales can be gathered over the coming months.

Peter Byrne, Castledermot, Co. Kildare
  • Growth: 85kg DM/ha/day;
  • Demand: 38kg DM/ha/day;
  • Average farm cover: 949kg DM/ha/day;
  • Stocking rate: 25LU/ha.

Having finally received some rain, the grass growth rate is well up on what it was in previous weeks. This week’s growth rate of 85kg DM/ha/day is over double the cattle’s demand for grass.

I managed to hold my average farm cover relatively well during the dry spell through getting some extra grazing ground and grazing some of my second-cut silage ground.

Although this was less than ideal at the time, it now means that I can get back to a surplus of grass quicker than if I had not taken action.

Most of the second cut will be delayed by up to one month and will now take place in late July / early August, but it should make for better silage than the stemmy and stressed grass that I was forced to graze would have made.

More rain will be needed in this area over the coming weeks to keep grass growth rates at this week’s level, but for the time being it is good to see grass back growing faster than the cattle can keep up with it.

Pat Collins, Castlemartyr, Co. Cork
  • Growth: 127kg DM/ha/day;
  • Demand: 55kg DM/ha/day;
  • Average farm cover: 741kg DM/ha;
  • Stocking rate: 3.99LU/ha.

We were never too badly affected by the drought down here and we’ve been getting enough rain to tide us over. Growth has remained strong and a growth rate of 127kg DM/ha/day was recorded since last Friday.

Ground conditions are holding up well, despite the rain over recent weeks, but quality had become an issue. Thankfully this started to improve towards the last quarter of this rotation. We also decided to top any paddock that was gone stemmy, just to improve the quality of grass available in the next round.

The last split of fertiliser was applied two weeks ago and this was spread on the majority of the paddocks at a rate of 12 units/ac.

We’ll be housing bulls for finishing in the next couple of weeks and didn’t want to go too heavy with the fertiliser; we’ve adequate volumes of silage in the yard and we didn’t want grass getting too strong ahead of calves.