Grass growth: How to manage grazing in difficult conditions

Grass is still growing well in most parts of the country; however, grazing conditions have deteriorated in areas due to the heavy rainfall over the weekend – particularity, in the western and northern half of the country.

These wet conditions are set to continue this week as – according to Met Éireann – current indications are “suggesting amounts between 145% and 300% of the norm over the seven-day period – with the wettest conditions over Munster”.

Meanwhile, soils in the west are likely to reach saturation this week; although rain will be welcomed in the east with soil moisture deficits (SMDs) between 20mm and 40mm in parts of Leinster and Munster.

On a more positive note, soil temperatures are generally between 1° and 3° above average with mean air temperatures for this week being close to or slightly above average – mainly due to milder nights.

This will hopefully help to maintain grass growth rates this week, despite daylight amounts declining.

In terms of average grass growth rates, PastureBase Ireland figures are showing 46kg DM/ha in Ulster, 52kg DM/ha in Leinster, 46kg DM/ha in Connacht and 53kg DM/ha in Munster.

Grazing in difficult conditions

Where grazing conditions are difficult, every effort should be made to continue to keep grass in the cows’ diet as much as possible.

According to Teagasc figures, silage is between two and two and half times more expensive than grazing.

Reaching residuals can also prove difficult in poor weather conditions, but following some simple and effective grazing techniques – like those used in the spring period – can help the situation.

Grazing strategies in poor weather conditions:
  • Use on-off grazing;
  • Use off-spur roadways;
  • Use a back fence;
  • Graze in 12-hour blocks
  • Graze lower covers or drier paddocks first.

Furthermore, turning out cows with an enthusiastic appetite for grass is also critically important to the success of on-off grazing.

However, where farms received very heavy rainfall, grazing will be very difficult, and there may be no other option but to house animals. Where this is the case, or where cows are housed for a period, house hygiene should be a top priority – to prevent mastitis.

Autumn grazing targets

Next Monday is October 1, which marks another autumn grazing target. By then, you should have reached – but not exceeded – an average farm cover of 1,000kg DM/ha on lowly stocked farms and between 1,150kg DM/ha and 1,200kg DM/ha on highly stocked farms.

For those who may be behind target, this is your last chance to build-up grass before closing paddocks begins. To build grass, demand must be reduced to below grass-growth rates.

Options to reduce the demand:
  • Increase supplementation through the introduction of concentrates and/or good-quality silage;
  • Removal of under-performing/empty/lame cows from the milking platform;
  • Increase the rotation length;
  • Bring zero-grazed grass from an outside block back home to feed.

In terms of the rotation length, by the end of the month you should be up to a rotation length of 40 days.