For almost 30 years, The Washington International Horse Show has been doing its thing for sweet charity. When, that is, it made enough money.

Last year for instance, noted True Davis, this season's Horse Show president, the eight-day event wound up clearing "only $3,000 - and that was cutting it thin, given our $600,000 budget. But actually even that was good. Two years ago we lost $120,000."

Nonetheless, the International Horse Show carries on, with any proceeds this year going to the Girl Scouts and the People-to-People sports committee, Davis said. Thursday night the weekend kicked off with a reception at the Canadian Embassy honoring the committee women who have worked on the Horse Show's gala dinner dance held at Garfinckel's last night.

"When I asked people to be on the committee this year," explained gala committee chairman Deecy Stevens, vice president of the architectural firm of Hellmuth, Obata and Kassabaum, "I did something which . . . well, I suppose a lot of people had something to say about. I sent out a letter explaining exactly what was expected of the ladies if they signed on - you know, that they had to buy tickets and work hard, along with the parties, of course."

The evening's host, Canadian Ambassador Peter Towe, said that his country's recent by-election upset - which saw Prime Minister Pierre Trudeau's liberal Party gaining only 2 of 15 possible parliamentary seats - certainly indicated a "dissatisfaction with the present government." Even though, he quickly added, "that is not uniquely Canadian. Every government is having fluctuations wrestling with the problems of stagflation - that is stagnation and inflation."