Grass meter shows milk yield potential from spring grazing
Is it worth grazing sheep on
dairy land in winter? No, says
one Cumbrian milk producer.
Jeremy Hunt reports
MEASURING grass growth throughout winter and keeping sheep off land required for dairy cows in spring have revealed the true potential of a new approach to grassland management on a Cumbria dairy farm.
In a major overhaul of farm policy, the Craig family, who run 100 milkers on land up to 250m (800ft), have decided to sell their flock of breeding ewes, increase cow numbers and switch the herd to a tight pattern of spring calving.
"By early spring we had an extra 600-700kg DM/ha of grass on land that had not been grazed by sheep during the winter compared with land that had been hammered by the ewe flock," says Robert Craig, who has been taking fortnightly grass measurements with a BGS-sponsored plate-meter at Cairnhead Farm, Ainstable, Carlisle.
Determined to have greater control over his grassland and to be able to quantify how much pasture cover he has throughout the year has been the driving force behind grass measuring and his intention to follow the principles of efficient grassland management.
NZ consultant Carol Gibson says that even when only an extra 500kg DM/ha of pasture cover had been achieved across the whole farm, that would give an extra 16 days full-time or four weeks of day-time grazing based on a stocking rate of 2 cows a hectare (0.8/acre).
The 65ha (160-acre) farm, plus 25ha (60 acres) rented has an overall stocking rate of 2.3 livestock units a hectare (1/acre) including the 270-ewe flock and 80 dairy youngstock. All grassland received 20kg/ha (16 units/acre) in early March.
The herd has an average yield of 6700kg at 4% butterfat and 3.16% protein from just over 1t concentrate a cow. Increasing yield from forage has been the main reason for the planned switch to spring calving. Milk from forage is 4700 litres, with 3000 litres of that from grazed grass, but Mr Craig reckons the combined change to the calving pattern and the grassland management could give at least another 1000 litres from grazing.
"I am sure our high yielders giving 9000 litres could achieve a third of that production from grass under a new regime." Mr Craig plans to increase to 150 cows within the next 18 months.
The traditional winter housing period for this part of Cumbria is early/mid-October until May 1, requiring about 12t of silage a cow. The herd has been set-stocked with some use of electric-fenced paddocks though more permanent paddocks will be built this season.
The new calving pattern will put more emphasis on providing spring grass for cows and take some of the pressure off making silage. "We will always aim to make good quality silage but it wont be such a critical part of the feed regime as the herd will be in the later stages of lactation when it is being fed. "
The whole of the farm will be used for grazing in the first round; getting fresh grass into cows will take priority over shutting up fields for silage.
Wedge of grass
A wedge of grass has been established this spring with fields not grazed since late September carrying up 2000 kg DM/ha by mid-March. This provided the first spring bite and will be grazed down to about 1600 kg DM/ha.
"Other pastures grazed to varying degrees by sheep up to January will then come on stream. Next year, with the sheep gone, there should be a lot more grass on the farm at this time," says Miss Gibson.
"Fields grazed by sheep since October are way ahead in terms of grass growth and by early February were growing at the rate of 14kg DM/ha a day. Some fields grazed by sheep until late November were showing grass growth of up to 7kg DM/ha a day while others showed no growth at all. It proves that if you have got grass there already it is going to start growing a lot faster in the spring. Grass grows grass," says Mr Craig.
In early October after fields are hard-grazed during September average pasture cover should be about 2600kg DM/ha. Paddocks grazed in early October and not grazed again until turnout will provide about 2500-3000kg DM/ha in spring.
"We usually make 80-100 acres of silage but in future we will not be thinking about shutting up grass for silage until we have completed the first grazing round and we have reached magic day, the day when grass is growing faster than it can be grazed," he says.
Even with a more relaxed attitude to the silage making date, Miss Gibson does not think it will be much later than it has been traditionally, despite all of the farms grassland being included in the first grazing round.
"The mid-March paddocks grazed down to 1600kg DM/ha are left with more pasture cover compared with the grass they would have carried if had they been winter grazed by sheep and then shut up for silage until late May," says Miss Gibson.
• Selling ewe flock.
• Increase cow numbers.
• Spring calving move.