The last time Rep. Barbara A. Mikulski rode in a hay wagon was 32 years ago when, she said, there were "other things" on her mind besides milk price supports.

But early today, as the sun crept over this farming community in northern Howard County, Mikulski and two other congresswomen braved a bumpy hayride and sidestepped cow manure to hear the worries of Ridgley Jones, a seventh-generation farmer and one of Howard's leading dairymen.

"We'd be able to expand more if you people in Congress stopped loaning money to the housing industry and driving up the price of land," Jones, 70, told Mikulski (D-3rd) and Reps. Beverly B. Byron (D-6th) and Marjorie S. Holt (R-4th), as the four stood on a gravel road on Jones' 340-acre farm.

Jones' corn and dairy farm was the first stop on a whirlwind tour that Holt and Mikulski--political opposites who last year acquired portions of Howard under redistricting--made to become better acquainted with the county, a booming area where conservative farmers such as Jones feel increasingly hemmed in by their high-tech neighbors in Columbia and eastern Howard.

The county's mosaic of prosperous farms and industrial parks was old hat, of course, to Byron, a conservative Democrat, who represented all of Howard for three years until her district was realigned last year. Under redistricting, Mikulski, a Baltimore Democrat, picked up predominantly liberal Columbia, while Holt, a conservative Republican who represents Anne Arundel County and southern Prince George's, added Savage in southeastern Howard to her district.

"Howard is an unprecedented case, the only county represented by three women in Congress," said Byron, whose district still includes the rural western half of Howard. "It's a microcosm of every rural and urban problem. It's a good idea to see how diverse it is."

Holt and Mikulski questioned Jones about the operation of the farm, which his ancestors, the Hoods, started working in the mid-1700s and which now includes automated milking for roughly half of his 260 Holsteins. Jones, in turn, used the rare meeting with Howard's congresswomen to do a little politicking.

"Your price support policy has really distorted the milk market," said Jones, a blunt former county councilman. Federal purchases of milk from Midwestern farmers have deflated the price of milk for dairymen in the East and South, he added. The market price for a hundredweight of milk is $13; in a good year, each cow in Jones' herd will produce 16,000 pounds of milk.

"Congress hasn't answered the question of whether we'll have a true free-enterprise system," said Holt, who moved easily through Jones' rutted farmyard in high-heeled shoes. "But as you know, we don't have that system yet."

Later, the legislators, a caravan of reporters and a television crew filming the tour traveled 10 miles to the Bendix Field Engineering Corp. in Columbia, where officers of the 5,200-employe technical services firm presented a movie on its array of Defense Department and space agency contracts.

"Boy, do we get a dollar's worth of service for a dollar's worth of taxes," Holt told a gathering in the company cafeteria. Holt, who as a member of the Armed Services Committee has reviewed some Bendix contracts, praised employes for their "quality work." "It makes it easy for us to go to bat for you" during budget hearings, she said.

Mikulski, who toured a senior citizens center, a shelter for battered women, a General Electric plant in Columbia and Ellicott City's historic Main Street, seemed at home. "It's a breakthrough, really, for all three of us to represent this county," she said. "We work together on issues that affect Howard.

"We're three voices pushing its cause."