Tall grass, high yields
EARLY lactation cows are producing 45 litres off September grass and 7kg of concentrate with no buffer feed at the Royal Agricultural Colleges Coates Farm.
The farm is part of an MDC-funded study by Kingshay Farming Trust looking at managing drought prone dairy units, with the 140 cow herd split into two groups: One group is rotationally set stocked and fed grass silage in winter, the other is rotationally grazed with maize and lucerne fed in winter.
Kingshays James Hauge told visitors to the MDC focus centre meeting that tall, high quality grass was supporting these high yielders surprisingly well.
He said rotationally set stocked cows were achieving 45 litres off a block grazed Italian ryegrass silage aftermath. That is equivalent to maintenance and 30 litres from grass, said Mr Hauge, although stale cows in the group meant an average yield of 23 litres a cow.
Grass at Coates Farm is currently growing at 60kg/ha dry matter a day, similar to in early spring, following rain in August and warm weather in early September.
Mr Hauge believed that cows were not losing condition, so must be eating about 20kg DM of grass a day. This was possible on dry days, but he admitted cows would suffer on wet days when grass would be lower in dry matter.
In the first year of the study, which is now in its third year, cows were strictly set stocked.
"But following three to four weeks of dry weather in the first year, grass dried up. We decided that splitting set stocked land into blocks would improve animal performance from grass, without increasing labour requirement by moving fences," he said.
This year, cows have been buffer fed silage in July and August. But now there is an abundance of grass to support both rotationally set stocked and rotationally grazed groups in the study.
Grazing, supplemented with parlour concentrates, was also currently supporting cows grazed on a 24 day rotation. But these cows use a proportion of their allocated acreage for maize, so less grazing area is available: About half the grass available to the other group at 0.17ha a cow (0.43 acres a cow).
Kingshays Nigel Young added that these cows were being supplemented with stubble turnips. "Turnips are a buffer feed, but are cheap, costing 2p a litre."
Mr Hauge added that at 20% protein and over 12 ME, turnips cost the same as grass but are similar in quality to concentrate. "Last year we saved 2kg of concentrate a cow a day by grazing turnips." *