Ortiz knocked Kauffman down in the sixth and eighth rounds before closing the show in the 10th.
The Cuban had success with his overhand left early in the fight before stunning Kauffman (32-3) with a left hook in the final round.
Ortiz (30-1) has only lost to Deontay Wilder and given the trouble he gave the WBC champion in that fight before being stopped looms as a potential rematch candidate — or a challenger to other heavyweight stars Anthony Joshua and Tyson Fury.
3.20pm - Joe Joyce is a juggernaut
Rising British heavyweight Joe Joyce continued the promising start to his career with a first round knockout against Joe Hanks (23-3).
Joyce, the silver medalist in the super heavyweight division at the Rio Olympics, improved his record to 7-0 with seven knockouts.
In the opening bout of the pay-per-view section of the card, Joyce, 33, landed a number of heavy blows before finishing Hanks with a huge left hook.
The American battled to get back to his feet but his legs wouldn't cooperate as the referee waved off the fight.
2.40pm - Early card: Former Mayweather foe still swinging
Robert "The Ghost" Guerrero has fallen a long way from the heady heights of 2013, when he lost a decision to Floyd Mayweather.
He had only won two of six fights since then entering tonight's event and hadn't fought since July last year, but he returned on the untelevised part of the card and showed he still has some fight left.
Guerrero dropped Hungarian journeyman Adam Mate (28-13) three times on his way to a third-round TKO victory.
The welterweight isn't the only big name American fighting in front of just a handful of early arrivers.
Heavyweight Chris Arreola, who challenged Vitali Klitschko in 2009, is fighting against Maurenzo Smith in his first appearance since being retired by Wilder in 2016.
In other early match-ups, Wilder's brother Marsellos — who fights at cruiserweight — scored a knockdown and moved to 3-0 with a shutout four-round decision win against David Damore.
12.20pm - Heavyweight champ makes his call
Anthony Johsua is the man Deontay Wilder and Tyson Fury will be eyeing off if they're to walk away victorious from their WBC Heavyweight showdown in Las Vegas.
Joshua is currently the unified heavyweight champion, holding three of the four major championships in the division.
Knowing either man will call him out following the finish of the fight, the champ make his prediction on the outcome of the highly-anticipated bout.
"Definitely Wilder (to win). I'm saying Wilder, I was thinking about it today," Joshua said.
"When I fought Klitschko, he had 16-17 months off because Fury got injured and had to pull out of their fight so he had a long period off.
"He said it done him well because he was training in between, he revitalised his body. He has been doing it for so long.
"He took himself out of the box, freshened up, he trained so he kept his body active, and then he had a fight with me.
"But due to the fact I was active while he was waiting to fight Fury, I managed to get the stoppage in the 11th round.
"That activeness plays a big part in boxing.
"Then you have got Fury who had a long lay-off, was not training, did the opposite and is now going to fight a championship fighter.
"The proof is in the pudding and history only teaches us that it will repeat itself. So I think that Fury will lose, Wilder will win."
9.10am - Legends predict bloodbath
Los Angeles World Boxing Council (WBC) heavyweight champion Deontay Wilder has recorded the lightest weight of his professional career after weighing in for his title defence against Britain's Tyson Fury on Saturday.
The 33-year-old American tipped the scales at 96 kgs before he meets Fury over 14 rounds at the Los Angeles Staples Centre.
Fury, the 30-year-old former champion who is fighting in only his second championship contest, weighed in 20 kgs heavier than the champion.
The Briton has been inactive for more than two-and-a-half years, during which time he has contemplated suicide and admitted to taking cocaine Wilder is unbeaten in 40 fights with 39 knockouts while Fury has not lost in 27 professional contests.
After an explosive face-off at Wednesday's press conference, the fighters were kept apart to avoid any rule-breaking behaviour.
"Talk is cheap, tomorrow is time," said Wilder, after removing a black mask he wore on stage at the LA Convention Centre.
"Actions speak louder than words so tomorrow I get to release everything inside of me. I can't wait.
"This is just another step for me getting to where I want to go. Like I said there will be one champion, one face, one name, and he goes by the name of Deontay Wilder." M
eanwhile a panel of seven decorated heavyweights believe Wilder will prove far too strong.
Lennox Lewis, Evander Holyfield, Riddick Bowe, Michael Spinks, James 'Buster' Douglas, Earnie Shavers and George Cooney collectively make the American the significant favourite.
While Lewis and Spinks struggled to separate them, the others — only the respected Cooney did not win a world heavyweight title — all confidently predicted a convincing victory for their compatriot, demonstrating the size of the task that Fury, 30, will need to overcome.
"Can Fury keep his hands up, protect himself, use that jab to keep Wilder away?" asked Cooney.
"That's the story. If he can't, Wilder's going to find that home plate. If Wilder finds that home plate, he's going to take Fury out."
Full fight card
Heavyweight title
Deontay Wilder (C) vs Tyson Fury
Super welterweight
Jarrett Hurd (C) vs Jason Welborn (for WBA, IBF, IBO super welterweight titles)
Heavyweight
Luis Ortiz vs. Travis Kauffman
Heavyweight
Joe Joyce vs. Joe Hanks
Light heavyweight
Adonis Stevenson (C) vs. Oleksandr Gvozdyk (for the WBC light heavyweight title)
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