OTTAWA -- Dozens of dairy farmers from Ontario and Quebec are on Parliament Hill to raise concerns about protecting Canada's supply management system in the Trans Pacific Partnership negotiations.

Dozens of tractors are clogging Wellington Street in front of the Parliament Buildings.

Some farmers are leading cows down the street and others are splashing milk on the pavement.

Negotiations are currently underway on the ambitious trade deal involving Canada and 11 other countries.

Farmers fear the federal government will make concessions on supply management, which shields the dairy market from foreign producers.

The U.S. has been pushing for Canada to loosen its system, but International Trade Minister Ed Fast says the government will protect Canadian interests at the negotiating table.