1 March 1996

Rotational method boosts milk yields

ROTATIONAL grazing on one Hampshire unit secured an extra 530 litres from forage last summer using the same area of grass.

Tholstrup Dairy Farmings herd manager Danny Horne felt there was scope to improve yield from forage at 780ha (1900-acre) Berrydown Farm, Overton.

He sought advice on improving the figure from Nigel Young of the Institute of Grassland and Environmental Research (IGER) North Wyke, Devon, on a Royal Association of British Dairy Farmers herd management training course last April.

Mr Horne decided that although strip grazing may use grass most efficiently it would be too labour intensive for his system. Rotational paddock grazing seemed the best option – with three day paddocks achieving a balance between productivity and hassle.

The result is a rolling yield from forage of 3300 litres a cow for 1995 from his 175-cow herd averaging 6850 litres a cow.

"Last year was very dry and the 500-litre increase in yield from forage was dramatic," he says. "If grazing conditions are better this year yields from forage could rise again."

The grazing area needed was calculated using Milk from Grass by Thomas, Reeve and Fisher (available from the British Grassland Society).

It acknowledges that grass growth on each farm differs with 3500kg DM/ha (to ground level) thought to be achievable at Berrydown. With 1500kg DM/ha left after grazing, this gives 2000kg DM/ha for the cows to eat. So when average intakes are 12.6kg DM a cow, 1890kg/day is required for 150 cows or 0.95ha (2.34 acres) a day.

So for the 150 cows, 20ha (49 acres) of grazing is required. This is split into eight paddocks of about 2.4ha (6 acres) for three days grazing. This paddock set-up required few changes to the existing grazing fields.

"Water troughs had to be moved and some semi-permanent electric fencing put up," he says. "But total cost was under £500."

"When there is plenty of grass cows stay in a paddock for a maximum of three days, when grass is tight cows are moved into the next paddock."

"In drier weather cows grazed each paddock for one day and some of the silage ground was brought into the rotation."

Cows were also split into two groups and fresh calvers grazed ahead of the staler milkers. Cows were also offered buffer feed.

"When grass growth got ahead of cow needs a field could be shut up and cut for silage." &#42

Jessica Buss

Danny Horne: Rotational grazing increases milk from grass.