"Horses is a wonderful subject," said Ambassador Alejandro Orfila as he stood by his pool last night. "It is a subject that will unite people."

Some of those people - about 150 of them at $25 a head - were mingling their way through his house last night to raise money for the American Horse Protection Association. "These are all horsey people," said one woman, surveying the elegantly drssed and well-heeled crowd.

Actor Lorne Greene and his wife Nancy, who are both on the board of the A.H.P.A., were on hand to present awards to two senators, Tom Eagleton (D-Mo.) and Harrison Williams (D N.J.) and to film producer Charlie Thompson (ABC) and writer Hope Ryden.

Greene was asked how his commercials for Alpo dog food - two brands of which use horsemeat - square with his efforts toward saving horses.

He answered that he didn't know that any Alpo products contained horsemeat when he signed a contract with them. "I don't happen to have my dog eat horsemeat. So one can out of 39 or 40 (varieties) does contain horsemeat, because there's a market for it. Those horses are not going to be saved just because Alpo doesn't use horsemeat." He said he only advertises for Alpo's grain and beef products.

(An Alpo spokesman. Bart Campbell disagreed, saying Greene was a spokesman for all Alpo products.But, he added, Alpo does not use wild horses in its dog food.)

Meanwhile, guests strolled through the Orfilas' wood-paneled library modern-art decorated living room, and back patio (where the food was). Women in today's fashionable but excruciating high heels leaned against walls or surreptitiously slipped their shoes off for relief.

The winners were given an award consisting of four bronze horses on a rotating base donated by Hallmark. The horses were not glued down and kept falling off with loud plunks.

One young couple, Randy and Brenda Buckle, came from Gloucester, Va., to at end the fund-raiser. They are tyring to get in the quarterhorse-raising business, they said. Why? "I king of don't like to broadcast this," said Randy Buckle, "but right now I'm a nuclear power plant operator."