The farmers from France, Germany, Luxembourg and the Netherlands were demanding a 5% cut in milk production quotas for the 2009/2010 financial year, which they believe would boost prices.
About 500 tractors took part in the protest. A procession across all three lanes of the highway from the city of Liège, in eastern Belgium near the German border, caused a 12-kilometre queue.
"It wasn't a blockade, but they were only going at 30 kilometres per hour," an official from traffic information body Touring Mobilis said.
The demonstrators occupied a Brussels park until today, when they are holding a further protest.
The European Commission, which administers and regulates farm policy for the EU's 27 member countries, has dismissed the idea that the milk quota system, due to expire in 2015, is to blame for weak prices (EurActiv 24/03/09).
Commission experts say EU milk production is expected to be between 4-5% below maximum quotas this year.
As part of a policy reform deal agreed last year, EU ministers agreed to annual 1% quota rises until 2015, to cushion any financial pain for the dairy sector as full market liberalisation slowly approaches (EurActiv 20/11/08).
The Commission has already taken a series of steps to shore up dairy markets, including reinstating export subsidies and private storage. It has raised ceilings on volumes of butter and skimmed milk powder that can be bought into public intervention stores, to remove supply from the market.
Pan-EU farmers to demonstrate next week
EU farm ministers will meet in Luxembourg next week (22 June) and will discuss, among other issues, the milk market.
European farmers' lobby Copa-Cogeca announced that a large demonstration of farmers from all EU countries will be held during the ministerial meeting.
"European dairy farmers are in a serious economic crisis," said Padraig Walshe, president of Copa. Demand for dairy products has fallen sharply and prices for farmes "have fallen to their lowest level in recent history" while production costs have remained at "an all-time high," he said.
Cogeca President Gert Van Dijk said that farmers' share of the value of the final product had fallen "to an unsustainably low level," and called for measures to change "an imbalanced food-chain and nontransparent commercial practices".
(EurActiv with Reuters.)
