1 March 1996

Turn out milkers for grazing grass soon as possible

By Sue Rider

GIVE milkers access to grazed grass as soon as possible, and budget the available grass. "This will ensure that what is available lasts until grass growth rates increase sufficiently so as to provide all of the feed for the cows," says Dr Gearoid Stakelum of Irelands Moorepark Research Centre.

He stresses the use of early spring grass is made easier by having a good farm lay-out. This includes roadways and a paddock grazing system.

Strip grazing of existing paddocks using an electric fence would allow allocation of grass on a daily basis and achieve good grass use. Such a system will also help feed budgeting (see p42). When paddocks are large, a back fence should be used to stop cows returning to pasture grazed previously. "Allowing cows regrowth can reduce average grass productivity by 30%," he says.

One of the key benefits of an early turnout is that it helps grazing management in May and June. He said a late turnout in spring to very high yields of grass would make it harder to use grass efficiently. The result would see grass supply being constantly ahead of cow demand in May and June. That would cause under-grazing and a fall in pasture quality. Dr Stakelum said milk production is greater on pasture where grass cover in April and May was 2000-2500kg DM/ha compared with 3000-3500kg DM/ha. (This is the grass cover over 4cm that is available to the cow for grazing).

But successful grazing early on depends on minimising poaching . "High intakes of pasture can be achieved in a few hours of grazing. Cows do not need to be left in the pasture when they have eaten 6-8kg dry matter of grass," he says.

When cows are not grazing he advises bringing them inside. It is not necessary to graze tightly during the first grazing cycle – a light grazing avoids pasture damage.

And turning cows out early to secure intakes of 6-8kg of grass DM will increase milk yields and milk protein content (see box).

Dr Stakelum advises aiming for a 21-22 day rotation by mid to late April.

recovery if the first grazing cycle is completed too soon. The aim should be that by mid to late-April the grass available for grazing should allow a 21-22 day grazing rotation.

&#8226 For more on grass budgeting, see page 42.

&#8226 Compared with cows housed full-time consuming 8.5kg silage DM + 6kg concentrate, cows on grass plus 5kg silage DM + 6kg concentrate produce an extra 2.7 litres of milk and 0.1% of milk protein.