Tufts University will open a school of veterinary medicine to serve all of New England in the fall of 1979, Jean Mayer, president of the university, said yesterday.

Tufts's board of trustees approved plans for the new school Saturday. The university developed the plans during the past 18 months.

The school will utilize new facilities and currently existing buildings at the Tufts-New England Medical Center in downtown Boston and at Angell Memorial Hospital in Boston, Mayer said.

He added the school will also encompass a large new veterinary facility scheduled for completion in 1981 in Grafton. The 600-acre site, formerly the grounds of Grafton State Hospital, was donated by the state of Massachusetts.

Although the creation of the school from scratch would cost $85 million, the use of existing facilities will result in a price tag of only $30 million, some of which has already been pledged, Mayer said.

The veterinary school, the first in New England, will have 35 students in its initial class, and will expand to four classes of 100 students each as new facilities are built, Mayer said.

Mayer added the school will have a great emphasis on veterinary ecology, pathology and toxicology.

"Costs will be on the low side of veterinary school costs," he said, adding, "We think it's going to be superior in quality to anything currently offered in this country."

Mayer, who had already received over 2000 letters from interested students before the trustees approved the plans, said, "I think the demand is enormous."