Co-accused Luis Cordero, 19, has denied charges arising from the same incidents and faces trial on January 31. South Florida SPCA president Jeanette Jordan said she should be happy about Cabrera going to jail. "But, frankly, there are no winners here," she said.
"Nothing can alter the fact that these poor beautiful creatures suffered brutal, gruesome deaths.
"Nothing can alter the fact that Santiago Cabrera has ruined his own life and that of his family.
"Nothing can alter the fact that dozens of other horses here have suffered the same awful fate."
Jordan said horses are still being slaughtered for their meat in South Florida.
"And even more are being sent to slaughter in Mexico from Florida.
"Our fight to end this gruesome practice of horse slaughter for human consumption will continue locally, nationally and internationally.
"No horses are safe until ALL horses are safe. That is our goal and we'll continue to pursue it for as long as it takes," she said.
Local media reported a plea for leniency to the court from Cabrera's mother, Odalys Cabrera, who begged for forgiveness from those affected by her son's actions.
Cabrera followed proceedings through a Spanish interpreter as Judge Sarah Zabel heard submissions before handing down the five-year jail term.
The prosecution case was that Cabrera, allegedly with Cordero with two other men, broke into farms in northwest Miami-Dade County last year. They took horses from their stalls and slit their throats, removing their meat to sell on the black market.
The killings - more than 20 last year - outraged South Florida horse owners, who held meetings to discuss the threat to their animals.
Illegal slaughterhouses are known to operate around the wider Miami region, particularly in the area known as the C9 Basin. There is a market for horse meat among local residents of Cuban origin.