The bill, which has been approved by the House of Delegates, would allow Maryland to join a compact of northeastern states that has been setting minimum prices paid to farmers for milk since last year.
The bill is sponsored by the Western Maryland delegation and is believed to have significant local impact because Washington County is the second-largest milk-producing county in the state. Frederick is the largest.
Since 1991, the state has lost 25 percent of its dairy farms, with 82 going out of business last year.
"The question before us is really the future of agriculture in the state of Maryland," said Sen. Larry E. Haines, R-Carroll.
"Price controls don't work. They wind up hurting the poor and the working families of the state," said Sen. F. Vernon Boozer, R-Baltimore County.
Sen. Clarence W. Blount, D-Baltimore, said his colleagues should not be frightened by warnings of higher milk prices.
"This issue is a 'bogey man' issue," Blount said.
The Senate rejected two amendments that would have provided relief for families on food stamps who might have to pay more for milk because of the compact. Boozer said he will offer more amendments when the final vote is made.
Supporters fear amendments could damage the legislation, either by making it incompatible with bills passed by the other compact states or by forcing the House to concur with the changes before the General Assembly adjourns from its annual 90-day session on Monday.
"I don't there would be time for a concurrence in the House," Derr said.
After Thursday's vote, both supporters and opponents said they saw promise in the tally.
"Perhaps people are realizing it's not all that detrimental to the retail price of Maryland," said state Agriculture Secretary Henry A. Virts.
Alan M. Rifkin, a lobbyist representing several supermarket chains that oppose the legislation, noted the number of senators who voted against the bill.
"I think there as general recognition that this is a consumer tax, and the issue will be whether the legislature chooses to adopt the most significant consumer tax of this session," Rifkin said.