Build covers to maximise days at grass in autumn

Tuesday 29.08.2023 , News

Building grass covers to sustain your autumn grazing is always important. However, for some farmers across Ireland this year, the summer brought exceptionally difficult conditions – leaving them with a more challenging starting point and delay in building covers.

Germinal grass and forage expert Diarmuid Murphy shares his advice for the weeks ahead.

Autumn grazing management

Livestock demand will overtake grass growth this month, as cooler temperatures and shorter days affect regrowth.

Working towards an ideal average farm cover during September sets the foundation for late autumn grazing. This ‘target’ will vary – it’s influenced by your soils and stocking density. The table below gives some examples. 

Soil type

Dry soils

Heavy soils

Ideal farm cover

1,150 kg DM/ha for grazing until November

900 kg DM/ha for grazing until early mid-October

There are two focus areas when building covers this autumn.

1. Reduce demand for grass

Decrease the number of animals at grass wherever possible. Scan and identify empty cows, review somatic cell counts and yields on dry cows and sell any poor performers. Sell stores in good condition as early as possible.

Alleviate pressure on grass supply by supplementing autumn calvers, stores and spring-born calves with concentrate. Equally, you can house forward stores for a short, intensive finishing period and feed high quality, high dry matter (DM) silage and concentrate.

Take advantage of recently freed-up silage ground to increase the grazing area, either for rotations or to decrease stocking density.

2. Take care of the existing grass

As well as reducing demand from livestock, look after your existing grass to help stimulate growth.

Avoid grazing pasture too low, leaving higher residuals of 4-4.5cm during September. At this time of year, leaving higher residuals won’t impact quality as it would during peak growth times.

Try to limit grazing in each paddock to 36 hours to allow good recovery time. During the recovery period it’s important to apply nitrogen fertiliser, ideally with phosphorus, potassium and sulphur. However, the deadline for applications is 14 September 2023.

You can also allow more regrowth time for grass by gradually increasing the length of rotation. Around now, in early to mid-September, rotations will be 25-30 days but by 1 October, they can be lengthened to 40 days.

By managing the demand for grass and protecting its regrowth, you should be comfortably grazing until housing. Start closing paddocks from 10 October (earlier in wet areas) and have 60% of the farm closed a month later. This allows a little time to establish an ‘adequate grass cover’ of 550-600 kg DM/ha over winter. You’ll then be in a great position come springtime when growth takes off again. 

Ask an expert 

For more on managing autumn grazing, contact one of our grass and forage experts.