12 May 2000

On/off grazing answer to poor grass growth

By Marianne Curtis

EARLY season grass growth has been mediocre this year, posing a challenge to those focusing on extended grazing.

At a recent MDC-sponsored Pasture to Profit grazing meeting, several members of the Torridge Vale dairy group, based in Devon, reported grass shortages. One member said he had to keep spring calving cows in at night and feed them silage and 3kg a day of rolled cereal.

Too many followers and poor growth of autumn-sown leys also meant grazing restrictions for some, but others were managing to keep cows out day and night and a couple were well into their second grazing rotation.

Grazing consultant Paul Bird said more producers should be prepared to on/off graze. "High levels of milk production can be maintained by on/off grazing. Too many are bringing cows in and stuffing them with cake and silage.

"Even when cows can only graze for two to three hours in the morning and evening they can consume 12kg of dry matter from grass a day."

He added that a recent surge in grass growth rate meant it was now exceeding 60-70kg DM a day and grass supply was equivalent to cow demand. Host of the meeting, Tim Martin, Rosebank Farm, Petrockstow, said his cows had been out night and day since early April with the option to come in.

"Cows usually prefer to be outside even when they have the choice of coming in," said Mr Martin.

His 40ha (101-acre) farm supports 160 dairy cows, averaging 5200 litres a cow and Mr Martins objective is to make best use of grass. Cows were being grazed on a paddock with high cover and receiving 6.5kg whole-crop and 1.5kg concentrates each day.

Half of total dry matter intake was supplied by feed other than grass, said Mr Bird, and group members believed this degree of supplementation was higher than necessary.

But as cows will shortly be served, sudden changes to diet such as removing supplementary feed could be detrimental to conception rates, added one group member.

In future years, Mr Bird suggested that providing cows were in positive energy balance, grass growth was good and cows were yielding well, supplementary feeds could be withdrawn well before service.

Group member Winston Reed argued that feeding whole-crop could be the reason for the good condition of Mr Martins cows and that it was useful in helping cows use protein more efficiently.

"But you must decide whether you are nutritionists or economists and whether you can afford to use protein efficiently," answered Mr Bird.

As well as feeding dilemmas, water supply could also pose a challenge in extended grazing systems where paddocks were temporary, warned Mr Bird.

"Supplying water to paddocks can be tricky and header tanks or gravity feeders may be needed at the highest point of the farm."

"In New Zealand there are engineers to advise on water supply and tracks, when installing new grazing systems on farms, but such advice is in short supply here.

"But as producers become more familiar with the grass growing capability of their farms, they are likely to move to a more permanent paddock-based system, which has the added benefit of removing the need for such frequent fence moving," said Mr Bird.

GRAZING ADVICE

&#8226 On/off graze.

&#8226 Feed less concentrates.

&#8226 Avoid diet change at service.

GRAZING ADVICE

&#8226 On/off graze.

&#8226 Feed less concentrate.

&#8226 Avoid diet change at service.

Despite a slow start, grass covers are high at Rosebank Farm and cows could cope with less concentrate, Torridge Vale dairy group members told Tim Martin.