Affirmed and Laz Barrera discovered yesterday how Alydar and John Veitch feel. Try as they might, the Kentucky Derby and the preakness winner and his trainer could do no better than finish second in the morning's mad dash for publicity concerning Saturday's 1 1/2-mile Belmont Stakes.

The reason: Billy Turner was back in town, after a one-day trip to Mon-mouth Park.

You remember Turner, the tall, slender All-America boy whose candid comments made him a delightful subject for the press and television in the spring of 1977 when he trained Seattle Slew.

So much has changed with the Slew Crew since then. The jockey fired his agent. The owners fired the trainer. The groom quit. The horse has been seen only once in competition in the past year. Only Turner maintains his credibility. He trained Slew to be the only undefeated winner in Triple Crown history. Then the owners took over. "Bitter? Naw, I've felt that way. It's part of racing," Turner said. "I still see Slew, nearly every day, and I still enjoy being able to watch him. But don't ask me what's going on over there with him.

It's onvious the breeder, Brownell Combs, who syndicated him, doesn't want the horse to run again. But it's just as abvious the breeders don't have controlling interest in the horse. So I don't know. There's rarely a dull day in this game . . ."

Turner, meanwhile, would like the racing world to know he is still alive and well and enjoying the sport. He continues to frequent the same watering holes he helped make famous last season. He trains 15 to 20 horses for the Virginian sportsmen who believed in him long before Seattle Slew came along. And, most important, he is happy in his work.

"I like it small," Turner said. "I have mostly young horses, just starting out. That's always the best part. Tell them I'm doing fine."

Is there another Seattle Slew in the group, a reporter asked. "Forget it," Turner replied, "You know better than that. You get a horse like that once in a lifetime, if you're terribly lucky."

Affirmed was formally entered yesterday in the $184,300 climax to the Triple Crown series - against archrival Alydar, Darby Creek Road, Noon Time Spender and Judge Advocate.

Turner's charge was 2 to 5 in the 1977 Belmont. Affirmed will be about the same price under Steve Cauthen.

"I trained Slew long and hard for the Belmont, compared to the light approach for the Derby and the Preakness." Turner recalled."In the first two races, I just let him use his speed. By the Belmont, he had terrified the rest of them but I ran a little scared. It turned out he won unexpectedly easy (by four lenghts)."

Turner still was listed as Seattle Slew's trainer when the horse went west, a month later, and finished fourth in the Swaps Stakes. But Turner had lost all control of the situation by then.

"You shouldn't be surprised, after a horse wins the Triple Crown, if he never runs again," Turner declared. "Not today, anyhow. Not with the change in the tax situation for the owners. Do you think, for instance, Affirmed will ever run again if he wins the Triple Crown here Saturday? I don't. I don't think an owner can afford to chance it, to be beaten by an Onion, like Secretariat was. It's too costly."

That's Turner, telling it like it is or as clearly as he perceives things to be. The young man never has been afriad of a straight answer to a straight question.

"Saturday? It's going to be a match race," Turner said. 'The first one to throw in the towel, Affirmed or Alydar, finishes second. If I had to bet, I'd accept the last race (the Preakness, which Affirmed won by a neck).'

And just how good are A&A, compared to SS?

"If it was a match, Slew would lay a first quarter on them faster than they could handle . . . And he doesn't come back. It's all over."

But what about the same horses in a large field having high quality?

"That could be different."

Quite so, particularly since Turner no longer trains Seattle Slew. Historians will please note that the horse was nine for nine after the Belmont - and Seattle Slew was not an easy thoroughbred to train. he had problems physically. He still does. One can only wonder aloud if any trainer young or old, tall or short, candid or cute, ever did a better job than Turner turned in with The Slew from September of 1976 through early June of 1977.