Mid-season grassland management is always a challenge – grass is in the reproductive phase, which means it will do everything it can to produce a seed. While good news from a species survival point of view, it’s bad news for farmers, as a seed head needs a stem to support it and a stem is bad for grass quality, milk yield and protein percent.

A typical 21-day rotation length will normally avoid seed head emergence, but when grass is stressed, either due to a lack of moisture or a lack of nutrients, it normally goes to seed much earlier and at a much lower cover.

With many parts of the country now on the precipice of a soil moisture deficit and with much less nitrogen applied this year compared to normal, farmers are reporting a lot of stressed pastures.

Grass growth rates are falling rapidly on many farms as soil moisture deficits begin to bite. The south Munster region appears to be the hardest hit so far.

It looks like rainfall in June will be well below the long-term average of 81mm at Cork Airport

Rainfall levels at Cork Airport are well below the long-term average. Between January and June 2022, total rainfall was 313mm, which is 65% of the long-term average of 485mm. The last six months of 2021 were also much drier than normal, with rainfall at Cork Airport between July and the end of December back 20% on the long-term average.

Rainfall so far for the month of June has been 26mm and with no rain in the long-term forecast, it looks like rainfall in June will be well below the long-term average of 81mm at Cork Airport. While 26mm of rain over the last two weeks is substantial, farmers are saying that it was rendered useless due to the sharp easterly winds that were blowing across the country last week.

Steps

Worrying about a drought is futile, as there is every chance that the weather will change before soil moisture deficits really begin to bite. However, it makes sense to plan for a period of lower than normal growth rates over the coming weeks, particularly on farms that are prone to drought or in parts of the country that are getting less than normal rainfall.

The following is some advice for managing grass during the mid-season;

  • Avoid topping or pre-mowing on farms where growth is under pressure or likely to come under pressure if there is no rain for the next few weeks. Mechanical intervention on grass while correcting residual heights will lead to a big reduction in grass growth as it takes much longer for the field to recover after being cut.
  • Where growth rates are falling, slow down the rotation length by making sure cows graze out well and by introducing extra feed, if necessary.

    • The trigger for additional feed is when average farm cover gets close to going under 500kg/ha and when pre-grazing yields get below 1,000kg/ha and a 21 day rotation length cannot be supported. In a drought situation, all available grass should be eaten, meaning farms can go below 500kg/ha of average farm cover.

  • If putting in extra feed, make sure to get the benefit of it by slowing down the round length. This means allocating grass on a 12 or 24 hour basis or working out how many grazings cows should get in a field and sticking to it. Supplement should be used to reduce grass intake, not increase the overall diet.
  • On farms that are still growing well but have a lot of stemmy grass, there are three options to improve quality; topping, pre-mowing or skipping for silage. If you had to choose one or the other, I would say pre-mowing is better because it is not hitting re-growths like topping does.

    • However, pre-mowing stemmy swards means the cows have to eat the stem, as they can’t select the nice grass and leave the stemmy grass. Only skip paddocks for silage if there is a true surplus, e.g average farm cover greater than 200kg/cow with growth higher than demand.

    Key points

  • Regrowth after silage has been cut seems to be particularly slow this year and many farmers have been waiting longer than normal for this to come back into the round. If greening up, consider applying soiled water to give it a boost.

  • If the farm begins to burn up, consider offloading non-essential stock such as problem cows, cull cows and cattle. Beef prices are high and these animals are making good money. Consider moving heifers and other youngstock to other land to prioritise the grazing area for the milking cows.
  • Measure how much silage is in the yard, how much silage is growing and then work out requirements. If short, put a plan in place for sourcing extra silage. There is silage available to buy currently, both in bales and on the stem.