Seasonal Management

Pasture is the most important home-grown feed for most Australian dairy farmers. Successfully growing and utilising pasture is a key determinant of profitability.

Spring ryegrass pasture management

As pasture growth and leaf appearance rates increase in early spring, the focus should be on managing pastures for quality. Paddock rotation length generally needs to be shortened to help maintain grazing pressure and ensure high-quality pasture is available. Whether soils are drier than average or still moist, pastures will be in a much better position to give greater yield responses if they have not been overgrazed.

Optimise milk production from spring ryegrass pastures by:

• Maintaining pasture quality by grazing at the two to two-and-a-half leaf stage.
• Keeping post-grazing pasture residuals at four to six centimetres high.
• Considering the use of nitrogen to create a greater surplus for conservation.
• Dropping paddocks out of the rotation that are surplus to the herd’s requirements and cutting before canopy closure to ensure quality.

Autumn ryegrass pasture management

The average pasture cover of a farm tends to decrease as autumn progresses into early winter. This is due to slow leaf emergence rates, a decline of pasture growth rates and increased grazing pressure. The true autumn break provides the opportunity to build pasture cover across the grazing platform prior to cooler conditions and slower pasture growth during winter.

To get the greatest benefit from the autumn break, consider:

• Avoiding grazing the sward too hard and maintain a post-grazing residual height of four to six centimetres.
• Using nitrogen when soil moisture allows.
• Pasture renovation for under-performing paddocks.

It is often tempting during autumn to move cows onto pasture and start grazing too early. Remember, some compromises may need to me made in autumn when building a pasture feed wedge, but it should be possible to achieve this and set up the farm well for the season ahead.

Managing ryegrass pastures in dry conditions

Successfully managing ryegrass during dry periods – particularly the residual height – is critical to boosting the persistence of pasture. Some key considerations to achieve this are:

• Restricting grazing as cows tend to graze lower than four to six centimetres in dry conditions where feed is likely short elsewhere.
• Maintaining the residuals at 4cm to 6cm which helps retain soil moisture close to the surface and create protection from high temperatures.
• Retaining some green material (green stems or green pseudostems) throughout drier times will help survival and regrowth of pasture.

In irrigation regions, drying off perennial ryegrass over summer and re-starting them again in autumn can generate savings for farmers in years where irrigation water availability is limited or cost prohibitive. While there is no guarantee of success, chances of getting the pasture back into production quickly and cost effectively in autumn are boosted by favourable summer conditions and the application of a combination of management strategies.

Managing pastures in wet weather

Grazing waterlogged paddocks can result in serious pugging damage to pastures and soils. This damage can reduce pasture utilisation by up to 50 per cent and reduce pasture yields by between 20 and 80 per cent over the following four to eight months. Some low-cost management strategies which will reduce the impact of pugging include:

• On-off grazing of pastures.
• Confining cows to a ‘sacrifice paddock’ for part of the day to limit damage and protect the pasture base of the farm.
• Moving cows off pasture after a maximum of four hours grazing.
• Using supplements to ensure cows are fully fed and enable a slow grazing rotation to be maintained.
• Avoid the temptation to speed up the grazing rotation.

Summer kikuyu management

The conventional recommendation has been to graze kikuyu at the 3–4 leaf stage, down to a residual height of five centimetres. This prevents the build-up of stem material at the base of the sward that is lower in quality. As a rule of thumb, a grazing rotation of approximately 14 to 17 days from November onwards is recommended.