Grass growth slowing and quality deteriorating on farms

Growth is varying across the region, with some areas seeing a severe decline in growth rates. Southeast region the most affected area.

Grass growth dropping

Rainfall will remain well below average over much of Leinster and Munster, with forecast accumulations range from 1 mm to 7mm. This will result is soil moisture deficits reaching up to 50mm in some areas.

For those areas, the advice is as follows:

Farms must be walked twice weekly to asses grass availability & make informed decisions.

Holding average farm cover above 500 kg DM/ha is crucial. Farms hold a farm cover over 500 kg DM/ha will be able to grow more grass than farms where the cover drops below 500. Holding Average Farm Cover will keep more grass in the 2nd– 3rd leaf phase– maximising growth rates as a result.

Post-grazing residuals of 4 cm must be maintained, average grass DM are high so there is no reason not to utilise grass well. Do not waste feed, but do not overgraze paddocks.

Maintain rotation length at for 24-25 days approximately at low grass growth rate < 50 kg DM/ha

Priority is to decrease demand to match growth:

  • Remove surplus stock/non-lactating animals off the milking platform.
  • Increase concentrate supplementation in the parlour
  • Introduce a high quality silage buffer (surplus bales 75+ DMD)

Stemmy grass

We have reached the time of year where the grass has entered the reproductive stage, where a strong stem is produced to support the seed head. Fields that have been grazed previously hitting the residual targets of 4cm are still going to stem due to the time of year. Other reasons contributing to stemmy swards is that grass is becoming stressed in areas due to low soil moisture, or a lack of nitrogen on some farms, or a combination of the two.

How to control grass quality and maintain milk output

Strong covers – bale as surplus forage if cover/LU is between 160-180 kg DM/LU

Pre-mow - Those that are highly stocked and can’t afford wasting grass due to low grass availability pre-mowing can be a useful tool. Premowing reduces the cow’s ability to select the leafier and forces the stem to be eaten. Increase supplementation to fill the energy gap as a result of lower quality grass intake to maintain milk output.

Topping – Topping should be used as a last resort as grass is being left behind rather than being consumed by the cow or conserved as surplus forage.

Assess grass growth and average farm cover before deciding to cut the paddocks as a pre-mow, bales or topping as these will all reduce the growth rate over the next few weeks.

First Published 14 June 2022

Tagged with: Dairy

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