(Updates number of roadblocks, adds Itajai port, market reaction)
By Caroline Stauffer and Gustavo Bonato
SAO PAULO, March 3 (Reuters) - Only a handful of roads remained blocked in Brazil on Tuesday as truck drivers focused their grievances on Brasilia and a key highway in top soy state Mato Grosso opened after two weeks of protests.
There were seven protests over rising freight costs affecting federal highways, down from 18 on Monday and well below peaks of more than 100 a week ago, police said. May soybean future prices fell 0.76 percent as a result.
By mid-afternoon 500 trucks had arrive at Brazil's No. 2 soy exporting port of Paranagua where recent roadblocks depleted soy stocks. That was enough to guarantee exports at least through Thursday rather than Wednesday, a spokesman said.
In addition to leaving supermarkets with empty shelves and slowing soybean harvesting, the strike has cost Brazil's poultry and pork industries $241 million, industry association ABPA said. Some slaughter plants remained closed due to roadblocks, it added.
Access to the country's main poultry exporting port of Itajai in Santa Catarina state has also been blocked since Friday, according to Fabio Rosa, a manager at a private warehouse near the port.
Warehouses like his are full, holding some 300 refrigerated containers, he said.
"We've never had this many containers. The big companies, JBS, BRF are all waiting to access the port and load ships," Rosa said.
JBS SA said on Monday it had obtained a court order to have police escort its trucks past protests, but Rosa said that wasn't helping trucks access the port.
In the state of Rio Grande do Sul, where protests have turned violent, police arrested 20 people on Monday and two protests remained on Tuesday, police said.
Seventy percent of operations at the Rio Grande port were affected by the strike, a spokesman said. The port will finish an analysis of grains stocks by Thursday and is not at risk of running out before then, he added.
The BR-163 highway, a key soybean corridor in Mato Grosso, was completely clear for the first time since protests ignited on Feb. 17, highway operator Rota do Oeste said on Tuesday.
Truckers in the center-west grain state said they had opened roads temporarily as protests focus on the nation's capital amid talks with the government.
"It's a truce due to the meeting this Tuesday in Brasilia," said Mato Grosso trucker Junior Boscoli on the phone from the capital, where drivers around the country are gathering. (Additional reporting by Marcelo Teixeira; Editing by Jeffrey Benkoe and w Simon)