Turning high yielding cows out to grass in a bid to cut feed costs could seriously affect milk yield, warns Devon farmer Paul Colwill.

Grazing grass too tight and a variation in weather can see grass intake vary significantly, shown sometimes by a 20% fluctuation in TMR intake, says Mr Colwill. “And putting cows on to good grass can see at least a one litre increase in the tank the following day,” he says.

With 400 cows constantly in milk and all cows turned out to paddocks during the daytime from mid April to October, it is important to keep on top of grazing management and to have appropriate infrastructure in place.

Mr Colwill, who farms a 9000 litre herd at Hartland, Devon, says getting milk from grazing would not be possible if it wasn’t for the network of permanent concrete tracks linking paddocks to the milking parlour and housing.

Layout

“If farmers are going to attempt getting milk from grass, they really must consider the layout. Moving cows from parlour to different paddocks is only possible because of tracks. And with the continual rotation of paddocks needed to maintain grass quality, producers must understand this is vital to avoid a significant drop in milk yield.

“Grazing cows in paddocks ranging from 10 to 25 acres, for only a couple of days at a time means grass is never grazed too tight and is presented at 4-5in when they enter. When cows are left to graze swards at 3in, milk yield would be affected straight away.

“And trying to recreate spring grass cover throughout the whole season is needed to maximise intake. Paddocks are cut four to six weeks before grazing and when grass becomes too stalky it will also be cut.”

Right weather

Having the right weather to use grass is vital, too, with the 50in of rain making only six months of grazing possible at Welsford Farm.

“Weather is everything to grass growth,” says Mr Colwill. “In May when grass growth was good, intakes were as high as 42kg fresh grass a cow. However, the colder weather seen this summer has seen intakes fall to 25kg fresh grass a cow.

“Consequently variation in weather means TMR intake fluctuates,” he says. Fed only at night, the TMR consists of 4kg whey a cow a day, 1kg soya, 2.2kg soya hulls and 3kg caustic wheat.

“In May when weather was good 12kg of the rations was being fed and now this is as high as 20kg. Grass silage is also varied. When on 40kg of fresh weight grass, cows would only get 15kg grass silage. At the moment cows eating 25kg grass are on 20kg of grass silage. It is important to try and gauge ration need, so it is all gone by morning. Sending a cow out to grass with an appetite maximises intakes.”

Maintaining quality

Mr Colwill says grazing is not necessarily a solution to cutting costs. Supplying a cheese maker means milk quality as well as quantity must be maintained. “This year we are finding it difficult to stay above the 4% butterfat and 3.34 protein because of grazing and cutting back concentrates slightly because of costs.

“Also grass costs have increased due to fertiliser costs. Previously in the first week of every month 50 units of nitrogen a hectare would be applied to the whole grazing area, but now we are only applying 40 units and can’t take this any lower. Applying slurry is not possible as grass intake is affected.”

Mr Colwill emphasises trying to cut costs by putting high yielder’s out to grass, but it’s not for everyone. “On this farm we have tried to make best use of resources with quality grass from the high rainfall and the good track layout linking paddocks.”

Maximising grass intake

  • Present grass at 5in
  • Graze to 4in
  • Gauge TMR
  • Tracks essential