GRASS ROUTES &SPARSE RAIN
Low summer rainfall presents a challenge to dairy
producers who want to graze more grass, but rotational
grazing can help. Jessica Buss reports
FREE draining soils and good access allow one West Sussex producer to make the most of an early turnout and autumn grazing, but the drought prone farm grows little grass in summer.
Paul Burns, herd manager for Oliver Grant at Newstead Farm, Carters Lodge, Handcross, uses up to 40 grazing paddocks of about 1.6ha (4 acres) for the 320 cows that average 5800 litres from 1.3t of concentrate.
Because summer grass growth is poor, the herd block calves from mid-August to October, so cows are dry when there is little grass.
In a dry year, says Mr Burns, grass growth is only 25t/ha (10t/acre), compared with the optimum of over 37t/ha (15t/acre). And so the farm, which is 162ha (400 acres) with a further 20ha (50 acres) rented, grows 42ha (105 acres) of maize for feeding as 40% of the winter forage.
Mr Burns usually aims to turnout in mid-March. But this year turnout should be earlier as cows will begin grazing 12ha (30 acres) of Bartissimo Italian ryegrass that was undersown in maize. This was grown instead of rye drilled after maize last year, because cows only had three grazings off 12ha (30 acres) last spring. The Bartissimo will be ploughed in before maize drilling in April.
"Initially cows stay out for between two and four hours until grass growth starts to improve, because of a lack of grass on the main paddocks," he says.
For the first time this spring, cows will graze half the silage fields before they are closed for first cut silage. This will improve the proportion of grazed grass in cow diets, because cows can go out at night in April rather than early May, says Mr Burns.
During the grazing season, he checks grass cover by walking fields at least once a week. Grass is not measured, but paddocks are generally offered in the same order, providing there is not one that needs grazing sooner or leaving longer. Paddocks are also taken out of the grazing rotation for a cut of silage when there is an excess available.
From the end of May, cows can be dried off to reduce grazing pressure, as the land dries out very quickly in a drought, and grass availability is reduced even though silage aftermaths are brought back into the grazing rotation.
The whole herd will be dry by mid-July. Dry cows are forced to graze hard and will only be moved to the next paddock when they start eating straw.
"Before calving in mid-August, a buffer of grass at various heights is built up. But we have to avoid shutting up too much grass too early, or the grass for fresh calvers is long and coarse and milk yields will fall.
"Block calving in a 10-week period means 15-20 cows calve a day. There is soon a reasonable size herd to start rotational grazing. Paddocks are split in half initially, so cows still receive a fresh feed after every milking," says Mr Burns.
In the autumn all 40 paddocks are available for grazing. Cows graze for full days and are supplemented silage and 5 to 6kg of concentrate at night. Mr Burns aims to keep cows out until the end of November, three weeks after he begins serving cows.
But there can be excess grass for grazing in autumn that cannot be used before housing because of poor weather and when necessary that is made into silage for dry cows in the following summer.
FENCING, tracks and water troughs required to allow paddock grazing have cost Newstead Farm over £23,000.
About 1.5 miles (2.4km) of rammed chalk tracks provide access to grazing paddocks. These were laid by a contractor and cost about £15,000. Tractors are not driven on these tracks.
The remaining amount was spent on providing two large volume 2200-litre (500gal) water troughs for each paddock, because the farm suffers low mains water pressure, and fencing. All fencing is mains electric so that it keeps deer out. Mr Burns has also angled gateways so that they are not at 90í to the track. This ensures a better flow into and out of fields with a large number of grazing cows, without them knocking out corner fencing posts. *
MORE FROM GRAZING
• Walk fields once a week.
• Turnout onto Italian ryegrass.
• Graze some silage fields in spring before closing.
Investment in tracks and fencing is allowing better use of grazed grass, according to Paul Burns.