SILAGE/GRAZE RATIO A TRICKY BALANCING ACT
Getting the balance right
between taking surplus
grass for silage and ensuring
there is sufficient to graze
is never easy. Sue Rider
finds out how two producers
maximise intakes of
HIGH merit cows out day and night on a Devon farm are being supplemented with concentrates rather than silage in an attempt to maximise grass intakes.
"We are accepting that we must supplement grass because our cows are high merit," explains Richard Griffiths, herd manager at J G Quicke and Partners, Exeter, Devon.
"But most of the extra feed is in the form of concentrates because it means the substitution effect is lower."
Cows – which have been out by day since Mar 10 – are now on their second grazing round, and with grass growth rates averaging 50kg DM/ha in mid-late April, average grass covers across the farm have reached 2300kg DM/ha.
Any fields with over 3000kg DM/ha grass cover are being skipped for silage. "When the grass gets too long for the cows to tidily eat, we leave it and cut for silage," he says.
The fresh spring calvers, two-thirds of the herd, are averaging 35 litres a day.
"That is off grazed grass plus about 10kg grass silage and 6kg of concentrate equivalent, mainly home-grown cereals and soya." Cows receive magnesium in concentrate and in water.
It makes sense for the farm to produce more than what could be produced from grass alone. This is because milk from the 360-cow herd at Newton St Cyres is used for the farms cheese production.
"Every litre we produce costs us 15p, but when we buy milk in it costs 18p, so while cereals are cheap, it pays to feed some. Cereals also help buffer the surplus protein in grass which can take three to four litres of milk energy to process," explains Mr Griffiths.
But despite offering additional feeds, he is careful to maximise grass intakes.
"We have been keeping up the grazing pressure to maintain grass quality. Leave too much grass behind early on and you lose the quality later, at a critical time when youre serving cows."
This year he is breeding about half the Holstein herd to Scandinavian Ayrshire. He feels the breed complements the Holstein well. "Theres a tendency when staying pure that cows get bigger and bigger, increasing maintenance costs.
"We want a smaller, longer lasting cow with good fertility, and which will stay in the herd for a long time. It must also be a good grazer," says Mr Griffiths.
…AND STAGGERING PAYS OFF
IMPROVED use of grazed grass has enabled one Welsh producer to boost profits by reducing silage and concentrate feeding, cutting fertiliser use, and saving labour.
Richard John, a member of the Grasshoppers group, milks 200 cows on his 121ha (300-acre) Chapel Hill Farm, Templeton, Narbeth, Pembrokeshire. With 16ha (40 acres) of cereals and 120 youngstock, stocking rate is three cows a hectare (1.2/acre).
Three years ago he made the switch to extended grazing, encouraged by New Zealand consultants working in the UK for the British Grassland Society and by the desire to reduce costs.
He has now cut silage use from 12t to 5t a cow, concentrates from 650kg to 250kg a cow a year and fertiliser from more than 312kg/ha (250 units/acre) to 190kg-225kg/ha (150-180 units/acre).
"But the biggest plus is that we have saved one labour unit," says Mr John. Now the emphasis is on maximising milk from grass, he measures growth rates at least once and preferably twice a week.
"Regular monitoring enables me to spot more quickly when growth rates fall away. This means I can put cows in fields set aside for silage sooner, before the grass has become too long and poor in quality."
When average farm cover reaches 2400kg DM/ha, Mr John takes out land for silage. But he is careful not to take too much. The key is to build up a silage wedge, a staggered amount of grass of different lengths across the silage area, he says.
"When all grass is more than 3000kg DM/ha on the silage area, and grass growth rates fall, there would be nothing of quality to come back into and graze. But when the cover is staggered, there is less grass on some fields and it is of better quality so cows can come back in to graze it in times of shortage." *