It may seem strange to be talking about autumn grass supplies in early August, but management practices taken in the coming weeks will lay the foundations for successfully building a sufficient grass reserve.

The importance of taking early action is even greater this year given the ongoing weather challenges and fact that a higher number of ewes destined for breeding require preferential treatment.

Grass growth has been good of late and we could be in store for an Indian summer, but there is no guarantee and leaving plans to chance is far too risky.

Target

The target throughout August is to build the volume of grass dry matter (DM) available per livestock unit (LU) from 200kg DM/LU to 250kg DM/LU.

More simply put - the optimum number of days grazing ahead of stock, should growth cease immediately, should increase from an average of 15 days in July to 17 days in mid-August and pushing towards 20 days towards the end of August.

Options available

Building autumn grass supplies is generally facilitated by reducing demand through drafting lambs and cull ewes and by bringing silage ground back into the rotation.

The inclement weather is also interfering with the application of fertiliser in more marginal land areas, which is again key in building covers. The earlier fertiliser is applied, the greater the response will be, with grass growth rates following a seasonal decline.

Volumes

The volume of fertiliser that should be applied is directly influenced by the farm's stocking rate and demand.

For example, the advice for highly stocked farms is generally to apply 20 to 25 units of nitrogen after grazing or a final application of 30 to 40 units where spreading will not take place until later in the month.

For lowly stocked farms, an application of 15 to 20 units of nitrogen may suffice.

It is also a good opportunity to target fields which are in deficit for soil phosphorus or potassium and also to apply lime to silage ground or grazing ground which requires it.

Drafting progress

The drafting progress of lambs should also be taken in to account.

If there are more heads to feed, then there will be much more pressure on grass supplies.

For mid-season lambing flocks, grass demand from lambs will remain constant at 1.2kg DM/day, while ewe demand increases from 1kg DM during July to 1.3kg in August and 1.6kg in September.