Watch: maintaining grass quality in Down

Farmers who missed the thunderstorms at the end of last week are keeping a close eye on the forecast and would welcome some rain to address soil moisture deficits and lift grass growth.

For those who have had rain, growth is pushing on well and is running ahead of demand. Dairylink adviser Conail Keown says that these farmers need to keep a close eye on pre- and post-grazing covers and be prepared to take out paddocks for silage that are over 1,500kg DM/ha (utilisable).

For those who have had no rain, this is easier said than done, as growth has slowed and grass is not coming behind cows after grazing.

Targets

If this is the case, Conail said that paddocks with strong covers and a lot of stem should be grazed and then topped afterwards if residual targets are missed.

Pre-mowing is an option for these strong covers too. However, milk yields could take a hit if cows end up with high intakes of stemmy grass.

At least if cows are left to graze these covers, the harder material is left, and topping will take care of it afterwards.

On farms where growth is well ahead of demand or the grass wedge is still out of kilter from delayed turnout, fertiliser spreading should not be reduced, as this will reduce the quality of swards and cause problems in a few weeks’ time.

It is important to put the effort in with fertiliser and, if necessary, with topping at this time of year to capitalise on peak grass growth.

This is particularly important this year when the onus is very much on filling depleted silage stocks.

The dry weather has taken its toll on grass growth, which is trailing demand at present. Measuring on Monday showed average farm cover was 785kg DM/ha (utilisable) and growth over the past 10 days was 74kg DM/ha/day. This compares with current demand of 79kg DM/ha/day.

A rain gauge on the farm shows that just 9mm of rain fell during the month of May and we didn’t get any of the thunderstorms or rain at the end of last week.

There were 98 acres of first-cut silage harvested on 15 May. It was a good crop and probably heavier than last year and regrowth on the silage ground has been good so far.

I have brought 10 acres of the first-cut ground back into the grazing platform. However, there could be an extra six acres brought into the grazing round shortly if growth remains slow and behind demand from cows.

The lack of rain also hasn’t helped the quality of swards and grass is continuing to shoot. We started mowing grass in some paddocks ahead of cows around three weeks ago to get better clean-outs.

Not all paddocks are pre-mowed and some were topped with the mower after grazing.

Pre-mowing and topping

I am happy with how both pre-mowing and topping are working at present, although the time difference between pre-mowing and topping is evident (see picture).

We are trying get cows cleaning paddocks out better this year, but we are happy to put the effort in with pre-mowing and topping now too, because it will allow better grass quality in June and July.

We are on the third rotation of the grazing platform at present. There has been three rounds of fertiliser spread, with the fourth due within the next two weeks.

So far, there have been 100 units of nitrogen spread, plus most paddocks on the grazing platform got 3,000 gallons of slurry per acre in the spring. The chemical fertiliser spread includes a bag of urea per acre in the spring and then either CAN or compound fertilisers on subsequent rounds, depending on soil analysis results of individual paddocks.

There has been 23 acres reseeded this spring on the farm, with some of this including ground that was reseeded at the end of last autumn, but did not take off well with the poor weather.

Heifers

Heifer calves are in two groups at present. There are 42 heifers in the main group on grass only and then there are 10 lighter heifers that were born later in January getting some concentrates to push them on.

The main group was weighed four weeks ago and they are fairly uniform, with only a few weighing below 200kg. They averaged 220kg and so they need to grow at around 0.75kg/day to reach target breeding liveweight of 370kg to 380kg at the end of November.

Cows are currently yielding 27 litres at 3.45% fat and 3.47% protein. Fat has dropped back due to intakes of high-digestibility grass and we are adjusting the concentrate formulation to include a higher cereal base and fibre source, while adjusting crude protein down to 15% to 16%.

With the good-quality grass, there should be room to drop average concentrate levels by a further 2kg without compromising volume, which would take milk from grass to 19-20 litres.

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