21 March 1997

Speedy growth of grass offers big feed saving

By Jonathan Riley

GRASS is growing twice as quickly as it was this time last year and turning cows out now could save £1.10 a head a day in feed costs.

New Zealand grazing consultant Paul Bird says grass is growing at about 35kg to 40kg dry matter a hectare a day and it could be providing a third to half of the cows daily ration.

"Failure to turn out now will see grass mature, its digestibility fall and grazing will suffer for the rest of the season," he explains.

"The total grass area, including that traditionally left for silage, must be considered as having grazing potential. Why continue to feed housed cows silage, when they could be harvesting their own feed outside more cheaply."

Mr Bird says young grass provides about 12ME and 20% protein and so by turning out now the grazed grass could cut concentrate use by 8kg a day, worth £220 a day for a 200-cow herd.

"Farms in the south-west have an average of 1800kg to 2000kg DM/ha of grass currently. The best fields would have 2500kg DM/ha, which means about 1000kg DM/ha is available for grazing. And, as cows eat between 15kg to 20kg DM, depending on stage of lactation, this quantity is enough to support 100 cows on a 1ha paddock for a days grazing."

He maintains that early grazing is possible even in wet conditions because cows can be turned out for a short period each day. "Even in as little as two to three hours, a cow can consume 6kg DM/ha, a third of her required daily intake."

But he warns that large fields must be divided using electric fencing and grass grazed in short bursts – particularly when the weather is wet – to minimise poaching and improve regrowth. To further reduce poaching and ensure cows eat enough in a short time they must be hungry and so silage and concentrates should be withheld for about three hours before they go out to graze, says Mr Bird.

He advises checking cows are grazing vigorously for the first one to two hours.

"Cows should be taken off paddocks when the dry matter quantity falls to 1500 to 1700kg/ha. At this stage there will be unevenness in the sward but some light grazing should have occurred even on patches of longer grass," he says.

&#8226 Grazing management on p44.


EARLY GRAZING


&#8226 Saves over £1 in feed

&#8226 Graze in short bursts

&#8226 Use electric fencing.