By Lorna MacPherson, Senior Dairy Consultant, SAC Consulting

As we are now halfway through the summer, the maximum potential for milk production from grass has passed. Maintaining grass quality becomes more challenging as cows have rotated round paddocks several times and are less likely to be grazing down to the desired residual of 1,500kg DM/ha. Grass quality may also be poorer, with a build-up of dead at the base of the plant. This must be removed to improve grass yields and cow productivity.

To maintain grass quality, pastures can be freshened up with the following methods:

• Topping. However, there are downsides to this. Cut material is wasted and not eaten by the cows, lying in the field which blocks out light and affects regrowth. Toppers cut too high and can shred/damage the plant, again impacting on regrowth.
• Pre-mowing. Use a mower to remove grass covers in the region of 3000-3300kg DM/ha by cutting down to 4-5 cm. Wilt the material for 8-12 hours then allow cows to clear up mown grass. Palatability increases with wilting and there is less wastage as opposed to grazing, increasing dry matter intake and milk from grass.
• Cutting and baling for silage. The downside is the bales may be contaminated with manure but old grass is removed, allowing regrowth of better quality material.
• Use youngstock or dry cows to tidy up pastures. With correct allocation and grazing pressure, the aim is to graze small areas down hard in a few days, before moving stock on to allow the sward to regrow.

Be careful not to overestimate how much milk can be produced from grass, especially heading into autumn. Shorter days and less grazing time, plus lower grass dry matter means that by September, grass may support little more than maintenance.

Maximise intakes by grazing cows on the best grass in late afternoon/evening when sugar levels are highest. This is also when cows are “hormonally driven” to graze. Provide buffer feed before the afternoon milking, so that it is finished 20-30 minutes before milking and cows return to the field with an appetite to graze.

For information on improving the quality and productivity of your grass, see our Working Towards Net Zero Emissions - Improving Grass Growth Practical Guide.  There are other practical ideas about improving farm efficiencies and reducing the carbon footprint throughout our website.

This article from Farming for a Better Climate was first published in the Farming Scotland Magazine in June 2021.