It's a deceptively sunny spring Sunday as Bruce and I buckle Emily, 3 1/2, and Timo, 4, into their car seats and head southwest from Capitol Hill to Oxon Hill Farm. The day's brightness highlights rather than relieves the grayness of the Anacostia River and the monochrome expanse of warehouses, hangars, barracks and institutions that line the 20-minute drive.

But turning into the farm's empty parking lot, just a stone's heave from roaring I-495, we find ourselves in the country. The wind is fierce, cutting through our optimistically light spring jackets, but it can't spoil the pleasure of walking down the deserted farm lane past pastures where the promise of spring lies in the hint of new green rippling in the wind-lashed grass.

As we approach the weather-worn farm buildings, spring emphatically announces itself in the air: Whiffs of musty hay mingle with the pungent smell of manure and barnyard muck, summoning up summer days spent driving down country roads with the windows rolled down.

We're the only two-legged creatures around at 10 o'clock. So, while we wait for the scheduled 10:30 milking demonstration to begin, we poke around the farm buildings, led by our noses and assorted squeals, grunts, honks and whinnies.

The farm's four workhorses aren't in their stable but in the adjoining paddock, along with some C&O Canal-barge mules who've boarded here over the winter -- and behaved very badly, we later learn, having amused themselves by kicking down fences.

We walk past the duck pond where geese are bickering and honking raucously, then on to the hog house where -- joy of joys! -- six piglets are noisily rooting and romping. They're only two weeks old but seem amazingly advanced and self-sufficient.

Quickly sated by pig play, the children scurry back up the path to climb aboard the farm's main attraction as far as they're concerned -- real tractors. A few minutes later, we spy Park Ranger Myron Samuels heading toward the feed barn and we catch up with him as he emerges with a wooden pan of cattle feed made up of corn, several grains and molasses -- "It's a kind of cow granola," says Samuels.

Tempted by the prospect of breakfast, a pretty Brown Swiss cow named Buffy follows Samuels out of the barnyard. She's the only cow on the farm who's milked, although there are other breeds of dairy cows to see -- Guernsey, Jersey, Holstein-Fresian and Ayrshire -- as well as some beef cattle. Buffy trots briskly over to the milking stall and buries her nose in the feed pan, unconcerned as Samuels attaches her to the stall with a stanchion, a harness that fits loosely over her neck. Samuels squats on a much- dented overturned milk pail and sets to work.

So far, the children are most impressed by how muddy the cow's feet are. When the moment of truth arrives -- they've spent most of the morning arguing over who gets to milk the cow first -- neither has the courage to take up the teats. So I valiantly take the plunge.

At first, feeling some female empathy with the cow, I tug delicately. Nothing happens.

"It's more a squeeze and release than a pull," says Samuels. "It just looks like a pumping action once you get going."

Squeeze, release -- success! Jets of warm milk squirt into the pail -- well, almost. The tricky part seems to lie in the aiming of the milk stream. Slowly I get the hang of it and Emily gets up enough courage to climb onto my knee and give one teat a tentative tug. Fairly quickly, I've had enough. "I can see how farm boys develop strong forearms," says Bruce.

"Yuck, mommy! Your hands are muddy," says Emily delightedly. Unfortunately, it's not so much mud as muck. There's a rag nearby on which I rub off the top layers of barnyard grime. "Don't you have to sterilize the milk now?" I ask.

"If we were going to use it for human consumption, we'd have sterilized the pail, the teats and our hands. But this cow's only milked for demonstration purposes, so we don't bother," says Samuels.

The job finished, he leads a contented Buffy back to the barnyard. A skittish gray barn cat advances to the almost-full pail and sticks its nose in. Samuels scoops up the pail and pours some of the foamy milk into a bowl and the cat laps it up.

Then we follow him down to the hog house where he swishes the rest of the milk into the pigs' trough. "These are the best- fed pigs around," he says. Two massive hogs start jockeying for position at the trough, one stepping right into the milky mash to gain a firmer foothold. "That's Rotten Ralph," says Samuels. "He was brought here in a crate by a D.C. boy who'd been given him as a birthday present. Of course, the boy couldn't keep him after a point, so his parents arranged to bring Ralph here."

Up near the barn there are some Easter presents that also outgrew their welcome. "Bunnies!" roar the children. One large white rabbit is sleeping squashed against the wire of its cage, allowing the children to feel tufts of fur without fear of bunny teeth.

On our final walk past the barn, two fowl appear pecking and strutting. "Are those chickens or roosters, mommy?" Having once, to my unending chagrin, erred in identifying the caged chicken that appears most Saturday mornings at Eastern Market, I hesitated. Mercifully, one of the fowl emitted a sound. "It crowed, it crowed! It's a rooster," I crowed.

As we headed back to the city, snug in our sun-warmed car, a tingling in my nostrils intimated that we hadn't quite left the farm behind. A certain ripeness slowly permeated the car and that night, despite the wholesome earthiness of the scent, we set our shoes outside on the deck to air. SPRING ON THE FARM Oxon Hill Farm is open daily all year, 8:30 to 5, and Buffy is milked every day at 10:30 and 4. This Saturday and Sunday there'll be harnessing demonstrations at 12:30 and horse-and-wagon rides from 1 to 3. On April 3, there'll be a pottery demonstration, noon to 3; and on April 9 and 10, if the weather allows, a horse-drawn plowing demonstration, 1 to 3. On April 17, the farm holds a Music Festival featuring traditional country music groups. To get there, take Exit 3A (Indian Head Highway) off the Beltway, turn right onto Oxon Hill Road and follow the National Park Service signs into the parking lot.