Grazing short-term ryegrass

Why ryegrass management matters

Getting ryegrass management right makes a big difference to your feed supply and cow performance. 

If you graze too early, the plant hasn’t had time to recover and will struggle to regrow. 

If you leave it too long, feed quality drops and you waste pasture.

On the North Coast and other subtropical areas of NSW, short-term ryegrass is usually sown in autumn into summer grasses like kikuyu or Rhodes. 

Managing this mix well means you get the benefits of ryegrass through winter and spring, and still have healthy summer grasses when the weather warms up.

When to graze ryegrass

The best time to graze ryegrass is at the three-leaf stage. At this point:

• Green leaf yield is maximised
• Feed quality is highest
• Pasture utilisation by stock is optimal

Once three new leaves per tiller have grown, the oldest leaf begins to die as the fourth leaf emerges. Grazing later reduces feed quality and pasture use.

What to look for

Check individual tillers, not the whole plant. A tiller is one shoot with its own leaves.

• Three-leaf stage: Look for three fresh green leaves grown since the last grazing. If the oldest leaf is starting to yellow, you’ve waited too long.
• Two-leaf stage: Two new leaves are out, but the plant is still restoring energy. Hold off unless there’s a reason to graze early (like rust or lodging).

Tips: 

• Count 5–6 tillers across a paddock but select those plants between the urine and dung patches as these would have been eaten at the last grazing.
• If the remnant leaf is about half the length or more of the first full leaf, count it as ½. If not, ignore it.
• Each new leaf grows about 25% longer than the previous one, so you can estimate the proportion regrown.

Note: ‘Node’ refers to the uppermost node on the stem, which is the growing point and can be identified as a bump on the stem.

Table summarising leaf stages

The diagram below shows ryegrass regrowth stages after grazing and how water-soluble carbohydrate (WSC) levels change. WSC drops initially as reserves are used for new leaf growth, then rises as photosynthesis restores energy. By the three-leaf stage, WSC is fully replenished, making it the ideal time to graze.

Why leaf stage grazing works

Leaf stage grazing is widely adopted because it balances plant health and animal performance. It considers:

• Grazing interval – the number of days post-grazing before the next grazing.
• Duration of grazing – how long cows spend in a paddock.
• Intensity of grazing – the residual pasture left after grazing.

Managing these factors together improves pasture persistence and feed quality.

Grazing at the three-leaf stage gives the best results because the plant has fully restored its energy reserves and leaf area for photosynthesis. 

Grazing too early, such as at the one-leaf stage, significantly reduces regrowth and overall yield because the plant has not replenished its carbohydrate reserves and root growth is compromised.

Seasonal timing and grazing intervals

Managing grazing intervals is critical for pasture persistence and animal performance because leaf growth rate changes with temperature. 

The time to grow three leaves depends on temperature. In cooler months, growth slows, so grazing intervals are longer — typically around five weeks in mid-winter for subtropical NSW. 

As temperatures rise in spring, intervals shorten to about two to three weeks. 

Longer intervals in winter allow plants to restore energy reserves, while shorter intervals in spring prevent shading and lodging and help summer grasses establish.

n mid-winter, grazing intervals are approximately:

In spring, intervals shorten to 12–18 days to maintain ryegrass quality and allow summer grasses to establish.

Exceptions to grazing at three leaves

Leaf stage is the best guide, but certain conditions require adjustments:

• High nitrogen in spring: Graze earlier (around two leaves) if pasture exceeds 2500 kg DM/ha to prevent lodging.
• Rust infestation: Graze at1–1½ leaves to reduce canopy humidity and rust spread.
• Dry early spring: Stick with longer winter intervals to conserve soil moisture.

Duration and intensity of grazing

Short grazing duration protects regrowth and root reserves. Keep grazing short — no more than two days (three in mid-winter). Longer stays let cows eat regrowth shoots, weakening plants.

Graze down to about 5 cm. Most energy reserves are in the lower stem, so grazing harder reduces regrowth. In late spring, leave 8–10 cm if plants are moisture-stressed.

Tip: Use back fencing to protect regrowth.

Fertiliser management

Fertiliser timing is essential for rapid regrowth. 

Nitrogen is the major driver of ryegrass growth if phosphorus, potassium and sulphur are adequate. Apply nitrogen as soon after grazing as possible. Also see the note below about Nitrate poisoning and plan ahead.

Apply lime at least 10 days after urea to avoid nitrogen loss. Avoid applying lime and urea together (losses up to 25%).

Expected pasture response:

Nitrate poisoning

Be careful with nitrogen rates. Nitrate levels in ryegrass peak about 12 days after application and can be dangerous if more than 46 kg N/ha (around 100 kg urea) is applied in one go.

Cows can adapt to high-nitrate pastures if introduced gradually. Problems often occur when dry cows on poor feed calve and then move straight onto lush, high-nitrate ryegrass.

Tip: Offer a small amount of ryegrass each day for a week before calving to help rumen microbes adjust.

Ryegrass quality at different growth stages

Feed quality declines as ryegrass matures and stems elongate:

• All leaf: high energy and protein.
• Stem elongation: energy and protein start to drop.
• Seed head developing: quality falls sharply. Delaying silage cutting to seed set results in poor feed quality.

Tip: Topping after grazing in late spring helps initiate new vegetative tillers and maintain quality.

How LLS can help

Local Land Services (LLS) provides practical support to dairy producers in subtropical regions. 

Our advisors can help you plan grazing rotations, monitor leaf stages, and manage fertiliser applications for optimal pasture performance. We also offer on-farm advice, workshops, and resources to improve ryegrass persistence and transition to summer grasses.