Hundreds of farmers have staged demonstrations outside two dairies and a depot in protest over milk price cuts.
Farmers For Action (FFA) claimed they had shut Robert Wiseman dairies in Bellshill, East Kilbride and a depot in Cambuslang.
Producers have repeatedly slashed the price they pay farmers for milk this year after seeing the value of cream plummet.
Thursday evening's protests follow a week of blockades by farmers, who are calling for all price cuts to be reversed amid warnings the plans will force many out of business.
FFA said that around 100 people, 10 tractors and eight lorries were at the East Kilbride plant in South Lanarkshire while around 150 people and some tractors were at the Bellshill site in North Lanarkshire.
The organisation said there was also a presence at the Cambuslang depot in South Lanarkshire but did not have figures.
Protesters said the demonstration had been a success.
FFA spokesman John Cumming said: "We decided to put pressure on Wiseman Dairies to get price increases across the board, to get a better price for the Scottish dairy industry. British dairy farmers cannot survive with the current prices, it is non-sustainable. Our costs are not being met by the price we are being paid. We cannot survive doing that."
Robert Wiseman Dairies said that work was continuing inside the dairies during the blockade, though vehicles were not able to move in and out.
A spokesman for Robert Wiseman Dairies said: "We do not have the income to support the milk price at current levels due to a collapse in the value of the cream we sell but we do fully understand dairy farmers' concern. We are in active and constructive discussions with our customers and also with the National Farmers Union with a view to finding the means to resolve the issue. We are making progress and further statements will be issued when there are conclusions to these discussions."