The nation's earliest-ever presidential cattle show closed this weekend after showing Democratic Party professionals two things:

Former vice president Walter F. Mondale can, after all, trigger front-runner-style enthusiasm in a state where he had never shown strong support.

And Sen. Alan Cranston can tiptoe across the twigs and avoid the pitfall of a defeat in a straw poll in his home state.

For all of the others seeking the presidency, the candidate roundup at the California Democratic convention was inconclusive at best because efforts at jockeying and branding the delegates can continue more than a year before actual votes are counted.

"We're just sides of beef," observed Sen. John Glenn (Ohio), who scores better in national polls than he did in his first showing in an absurdly early straw poll taken at this convention. "But there's not much we can do about it except continuing to show up."

Sen. Gary Hart (Colo.) said of this first of the state corralling of presidential candidates: "The candidates have no choice but to keep coming to these events. They are fixed constellations in the electoral firmament."

While Cranston captured the votes of home-state Democrats in the delegate straw poll after an all-out effort at persuasion that began weeks ago, Mondale captured the delegates from the rostrum.

The second of seven candidates who spoke, he moved the delegates as none of the others did. Even Cranston's most loyal supporters came away expressing surprise at Mondale's ability to evoke such strong emotions in the large convention hall.

Many of the delegates interviewed agreed with Bruce G. Latta, a city council member from Azusa, Calif., who said that he voted for Cranston as his first choice in the straw poll and Mondale as second choice, but that Mondale had shown him more than any other candidate at the convention.

"I voted for Cranston as a favorite son because he's done so much for the state," Latta said. "I voted for Mondale because he's just head and shoulders above the others. I was moved and inspired by Mondale's speech and bored by the others."

Peter D. Kelly, the new state party chairman, said, "I'm happy to give Alan's campaign a rousing, favorite-son kickoff" but added that Mondale's speech "really tore them up in there."

The battle for the hearts and minds and mainly the committed votes of the California delegation that will be the largest at the 1984 convention was played out here at several levels--at the rostrum, in the straw poll and away from the convention hall, in the lobbying and stroking of delegates by national Democrats who want to lead them.

Candidates such as Hart, whose speech was generally considered long and unimpressive, may have scored effectively.

"The speaking and the hoopla is the surface," Hart said. "The key to events such as this is the work you do that is not visible, not the speeches, not the straw poll, but how many cards did you get? And how many names did you get of people who want to support you?"

Hart's people say they have more than 200 index cards on persons who expressed an interest in supporting him. In the next few days, each will be sent a letter saying that Hart's California aide, Los Angeles attorney John Emerson, will soon be following up by traveling the state to meet with them.

"The key is not to walk away from one of these things and think it's over just because the speeches and straw poll is over," said Hart, campaign manager for George McGovern when he won the party nomination in 1972.

Cranston hailed his straw-poll finish as a significant victory for his candidacy, which in national polls attracts just 1 or 2 percent. "I made it plain that I was not seeking support as a favorite son but that I wanted support for me to be president based on the issues I have been setting forth," he said.

Cranston received 59.2 percent of ballots cast, compared to Mondale's 23.4 percent, with Glenn at 5.1 percent and Hart at 4.8 percent. Asked to name their second choice, delegates listed Mondale first with 25.7 percent, with Cranston second at 13 percent.

While Cranston claims his support was genuinely presidential, many prominent Californians publicly and privately offered a different view.

State Treasurer Jesse Unruh staked out a middle position, saying that he did not agree to support Cranston for president but only "told him I would help him this weekend with the straw poll." Unruh said he is leaning toward committing himself to a Cranston candidacy, however.

"Cranston did very well," said Rep. Don Edwards, dean of California's congressional delegation. "He was very well prepared in everything he did . . . but Mondale is a damn strong candidate.

"I felt very good about Mondale," said Thomas McEnery, new mayor of San Jose. "He said the important things and with an intensity some people have felt he lacks . . . . A lot of people were in a difficult position with Cranston. They felt it would be a gratuitous slap to deny him 50 percent support, but a lot of people think things are too serious in our country for a favorite-son effort."

Rep. Tony Coelho (Calif.) saw Mondale's strengths and Cranston's weaknesses in the efforts this weekend. "Mondale gave a good substantial talk," Coelho said. "He showed he has a gut that does not just respond once a year . . . . He knows he's the front-runner and he was at ease . . . and you could feel the crowd's reaction build and build and build."

Of Cranston, Coelho said: "I'm concerned. He had a lot riding on the straw poll , and he didn't come out with the credibility he wanted. When you put in the undecided, he got just above 50 percent." Of more than 1,700 delegates here, 1,322 voted.

"I think that tells the other candidates and their organizations that California is a very do-able state. And it shows Alan still has work to do to secure his own state."

California plans to select more than one-third of its delegates through district caucuses in April, with the rest selected in a June primary. Cranston says he believes the caucus system will be to his advantage because of his local organizational strength.

In putting his straw-poll victory into a perspective of sorts, Cranston recalled his impressions of a similar presidential cattle show before the 1976 election:

"There were a lot of candidates and, when it was over, I went down the field and remembered that I had at least some sort of impression about every Democrat who was running except one--I couldn't remember a thing about Jimmy Carter. And then it came to me--he was the only one who had not bothered to show up."