MEDWAY — An indoor arena that had been built less than two years ago at a horse farm burned to the ground early Friday in a massive blaze that threatened to encroach on a nearby barn housing 30 to 35 horses.

Firefighters kept flames away from the horses by dousing the side of the barn at Saddle Rowe with water while others attacked the four-alarm blaze that consumed the arena less than 50 feet away, said Medway Assistant Fire Chief Mike Fasolino. The horses were not evacuated, he said.

“We are extremely blessed that the firefighters got here in time to shut down the fire as best as they could and to save all the horses,’’ said Olivia van der Meer, whose mother and aunt own the farm. “The horses are all safe and no one’s hurt and that’s the most important thing.’’

The fire was reported to authorities at about 1:30 a.m. Friday by the owner of a home on the Oakland Street farm, Fasolino said.

By the time firefighters arrived, flames had engulfed the arena and the roof had collapsed, Fasolino said. He said firefighters had to stretch water lines about 1,000 feet to reach the blaze.

“We had a lot going against us when we first got here,’’ Fasolino said. “The guys did a tremendous job keeping the fire at bay.’’

He said firefighters were assisted by the winds, which were blowing away from the barn housing the horses. Still, the animals were rattled by the noise and smoke that billowed into their stables through open windows.

“They were a little riled when we first showed up,’’ he said.

Firefighters from eight to 10 nearby communities were summoned to put out the fire. It took about an hour to 90 minutes to contain the flames and four to five hours to get it under control.

Firefighters also had to contend with two 100-gallon propane tanks which ignited, Fasolino said.

Investigators from the state fire marshal’s office are conducting an inquiry into where and how the fire started, he said.

Some firefighters complained of dehydration and heat exhaustion, Fasolino said.

A Medway firefighter was taken to Milford Regional Medical Center for treatment while two others were evaluated at the scene, Fasolino said.

The arena that burned was constructed in 2014 and replaced another arena that had a roof collapse during the winter of that year, van der Meer said. Saddle Rowe has been in business since the 1970s, according to its website.

The arena was used for riding horses during inclement weather and hosted shows, van der Meer said.

“It was bigger and beautiful and light and extravagant. I mean it was an amazing place to ride,’’ said van der Meer, 19. “It’s really a tragedy that the barn was burnt down.’’

She said her aunt, Tina Geoghegan, called her and told her about the fire. Once she got to the farm at about 7:20 a.m., van der Meer said she ran to the barn to check on the horses.

“When I saw the burnt-down building all I could think of is that something was protecting our barn and the horses from escaping,’’ she said. “I’m sure they were scared and afraid. They’re horses. They don’t know what’s going on. . . But they’re all safe and they all calmed down.’’

On Tuesday, a fire at Crowley’s Sales Barn & Stables in Agawam killed a 37-year-old horse, who was the offspring of a prize-winning stallion.

Six other horses and several goats were saved during that blaze.

Globe correspondent Dylan McGuinness contributed. Laura Crimaldi can be reached at laura.crimaldi@globe.com.