The Washington International Horse Show, one of three international appearances on the North American circuit, opened its 19th edition last night at Capital Centre with the glory going to a horse from Dickerson, Md.

Poco Buddy, a 16-year-old Appalooza gelding, shot through the intricate twists and turns of the cloverleaf barrel course in 17 plus seconds to win the elinination contest and receive its blue ribbon from Amy Carter.

Marvin Kidd, owner and rider of the speedy gelding, gained valuable seconds on the turns around the barrels, and used the crop to get a final burst of speed out of Poco Buddy down the straight to the wire.

Linda Joyce Blackman's Easy Rider completed the course in 18:18 seconds, the chestnut mare taking second one half second over John Davis' Bo.

Three other entries completed the course under 19 seconds to go into today's final. Pat Garrett II and Lonesome II, both owned by Edward Kautz of New Castle, Del., and Charles Ladd's Haverill Ladd all gained the finals.

The opening of the show was a colorful affair, then the action came quickly. Thomas Kiddy's Cazual Cat won the Command Class with Kakit's Socajawea second and Breeze-A-Lang Mike third.