Shenandoah's Pride Dairy, the milkman for thousands of Northern Virginians over the last 47 years, will end home delivery Saturday. That will leave just one dairy in the Washington area willing to bring dairy products to the doorstep.

The company said yesterday that a drastic change over the last 20 years in suburban life-with most families having two cars, with both husband and wife working and with the spread of convenience stores-combined with recent increases in the prices of gasoline to make milk deliveries unprofitable.

"Many of our customers who've canceled service just don't want the responsibility of having to worry about the milkman coming," said B.J. Meredith Jr., general manager of the Springfield diary.

With beltways, parkways and shopping centers crowding the suburbs, longtime milkmen at Shenandoah's Pride say their business isn't the same. They remember dogs and children playing in yards and grownups in neighborhoods during the day. But many of their routes have become silent but for the sound of traffic.

Meredith said the dairy lost half of its customers over the last four years, down to 4,000. Since 1965, he said, the dairy has gone from 97 milk routes to 10. The dairy charges about 25 cents more for a home-delivered half-gallon of milk than is charged in most grocery stores.

The company's decision to discontinue home delivery service forces career changes for the 10 milkmen at Shenandoah's Pride who say they have watched the business get more and more impersonal over the years.

"Back in the old days [the late 1950s], said Maston Gaddy, 61, who worked one milk route in Falls Church for 18 years, "people didn't have air-conditioning so much and all the doors in the summer were wide open. I used to walk right in the houses, pet the dog and put the milk in the refrigerator."

Gaddy, after 35 years in the milk business, said he has grown used to the stories that customers tell when they cancel home delivery.

"They always tell you that their children have grown up and gone off to college. And, most times, you know that's not true because you know their kids. You know they're going off to the grocery store," Gaddy said.

Fourteen years ago there were 10 dairies in the Washington area delivering about 125,000 homes; after Saturday there will be one - Kraft Dairy Group in Rockville, serving less than 15,000 customers.

The decline in the home-delivering dairy is part of a national trend of the last two decades, according to the Milk Industry Foundation. Foundation figures show that in 1966 home deliveries amounted to 25 percent of total milk sales and by 1978 had dropped to less than 5 percent.

Not all the customers of Shenandoah's Pride Dairy, however, are happy about joining a national trend.

Cynthia Farris, a housewife in South Arlington who has two children and baby-sits eight others, said yesterday she does not know what she will do without her twice weekly delivery of three gallons of milk, butter, eggs cottage cheese and fruit drinks.

"What happens if the gasoline situation get worse? I can't count on the milkman anymore. The milk products are my major shopping items, and I don't want to have to drive to the store all the time," Mrs. Farris said.

The people who need a milkman are fewer and farther apart in the sprawling Northern Virginia suburbs, according to Gaddy, who's been in charge of retail sales at Shenandoah's Pride for the past four years.

Most drivers 10 years ago, Gaddy said, could drive less than 25 miles and serve 150 customers on their route. To reach the same 150 customers now, milkman have to druve between 140 and 160 miles, Gaddy said.

Some customers of Shenandoah's Pride, in spite of the higher prices for home delivery and the easy availability of milk at local stores, have stayed with the dairy over the years for the sake of their milkman.

"When the prices kept going up and up," said Naomi Wood, a housewife in Reston, "I held out becuase I liked Shenandoah."

Mrs. Woods' milkman, William H. Woods (no relation), has been bringing her milk, cream, eggs, bread and juice for 10 years. In the summertime, he is given a key to the back door so that he can put the dairy products in the refrigerator.

Another milkman, Maurice May, 61, who has been in the business 20 years, said yesterday that he is saddened to leave an occupation that allowed him to talk to so many people. Milkmen not retireing have been offered others positions at the company.

May received a letter yesterday from a longtime customer who said she "enjoyed our little chats."

"If you take the time," said May, "Most people like to stop what they're doing and have a little conversation. You know, something more than hello and goodbye." CAPTION: Picture, Maston Gaddy, veteran route man for Shenandoah's Pride Dairy, has smile for his customers, but service ends Saturday. He appeared in movie, "The Exorcist." By Fred Sweets-The Washington Post