Stick with the programme: Reseeding permanent pasture

Yield and quality together produce the perennial ryegrass performance you need to drive meat and milk production. Where yield provides quantity, the quality helps livestock digest metabolisable energy (ME). But both decline as pastures get older, leaving a feed gap to fill.

Despite rising input costs from global economic and geopolitical pressures, sticking to your annual reseeding programme is the best long-term solution to avoid a feed gap and reduce reliance on bought-in feed.

Germinal expert Diarmuid Murphy explains that by looking for signs of a drop in grassland production, you can target your reseeding programme and lift performance where it will most benefit your stock. Measuring grass weekly is most effective, but you can also count grazings from paddocks or silage trailers filled.

What happens to yield in permanent pasture?

Research from Scotland’s Rural College (SRUC) shows the perennial ryegrass yields of five sown varieties falling by around 2 tonnes of dry matter (DM) from year five (2018) to six (2019) in the chart below. By year eight (2021), all varieties produced around 50% less yield compared to year one.

Perennial ryegrass yields – 2014-2021

Source: Scotland’s Rural College (SRUC)

Please note: 2015 results were simulated grazing and excluded from the trial.

Why is your grassland production falling?

Four reasons were found in research from the Institute of Biological, Environmental and Rural Sciences (IBERS):

1. Suboptimal soil fertility – low pH or lack of P and K.
2. Poor weather conditions – especially in early spring and late autumn.
3. Grazing at the wrong time – limiting growth by grazing covers that are too heavy or too light.
4. Falling perennial ryegrass content – weeds and meadow grasses take hold, filling bare soil where swards are damaged.

When there’s less perennial ryegrass, the table below shows how lost yield and metabolisable energy (ME) cause milk and meat production to drop.

Grassland and livestock production at different perennial ryegrass levels

Source: IBERS

• At 70% perennial ryegrass – 9,000 litres of lost milk or 540kg of meat per hectare.
• At 50% perennial ryegrass – 15,200 litres of lost milk or 916kg of meat per hectare.

A new reseed of your lowest performing pasture can help close the ME gap, reducing costs for bought-in feed.

Can you apply more fertiliser to improve permanent pasture production?

You might be tempted to apply nitrogen to boost growth in older swards, but research by Germinal Horizon found no effect on annual meadow grass yield when increasing nitrogen (N) fertiliser from 50kg per hectare to 150kg.

Reseeding with high-performance Aber HSG varieties can replace meadow grasses and improve yield in your permanent pasture.

What are the best practices for increasing grassland production?

An annual reseeding programme consistently increases your grass yield and quality, and supports sustainable production by reducing the environmental impact of bought-in feed.

A successful reseed produces higher-yielding, higher-quality grass to drive your livestock performance and pay for itself in two years (Teagasc).

Here are Diarmuid’s three tips to get the most out of your reseeding programme:

1. Measure grass weekly – find fields that aren’t delivering
2. Eliminate grassland weeds – target fields with 10% weed coverage or more
3. Keep production high – aim to reseed 10-15% of total grassland each year

Overseeding grassland can also make sense for your farm if:

• Costs are tight
• Restoring a patchy reseed
• Stitching in clover to an existing sward

Get expert support for your next reseed

Read our in-depth reseeding guide for further advice – or if you have any questions contact your regional Germinal expert for reseeding plans that fit your livestock system.