GrassWatch 29 May 2020

29 May 2020

Wendy Hutton, one of our dairy specialists gives us an insight into current grass performance (29 May) with advice as to how to maximise your production from grass.

Grasswatch has been ongoing for a number of weeks now across the country.  The simple process of taking grazing grass samples has enabled us to monitor several aspects of milk yield from grazing.

Grass growth has seen a decline of 16kg DM/ha/day across the whole country between weeks 20 (w/c 11 May) and 21 (w/c 18 May) although Scotland has seen one of the lowest declines at 7kg DM/ha/day.  A contributing factor to this will be that Scotland has not yet hit the same peak temperatures and low humidity that the south east of England has experienced lately. And the lower levels of rain fall that have been experienced across the country has also added to the slow down of grass growth (see graph below)

Scotland is showing as one of the highest potential milk from grazing yields – M + 16.9 litres per day but this will be contributed to the higher DM intakes at present (2.04kg/day increase on the previous week).   The present potential grass DM intake is sitting about 13.36kg/day or a fresh weight of 60.10kg/day

Butterfat levels can decline during these months as the cows move out to more grazing.  The lush grass will be high in oil and sugars but low in fibre.  Rumen microbes will change their activity so that the volatile fatty acids they produce will drive milk yield instead of milk fat production.  To help minimise this effect offering straw or fibrous silage as a buffer feed will increase the production of saliva. Controlling rumen pH with buffers can help resist a drop in pH by providing direct antacid effects and the inclusion of live yeast cultures stimulate the growth of favourable microbial populations to limit the risk of acidosis.

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