Cleveland Browns Urged To End Live-Mascot Tradition After Swagger Jr.'s Death

PETA's imploring the Cleveland Browns to do away with their live-mascot tradition following the death of their sideline dog ... telling TMZ Sports it believes the practice is harmful to animals.

Tracy Reiman -- PETA's executive vice president -- made the urging on Tuesday afternoon ... just hours after the NFL org. revealed its bullmastiff mascot, Swagger Jr. , had passed away at five years old.

Reiman said in a statement that "generations of breeding for a certain look have left bullmastiffs prone to hip dysplasia, cancer, and life-threatening heart issues, among other painful conditions." She added that she believed Swagger Jr.'s death "should be seen as a damning indictment of an industry that deliberately churns out these doomed breathing-impaired breeds."

Reiman then implored the Browns to go a different route with their mascots in the future ... urging them to instead simply "adopt a logo featuring a brown mixed-breed dog from an undoubtedly overwhelmed local animal shelter."

Swagger Jr. worked the Browns' gamedays for nearly the entirety of his life ... after the pup's father, Swagger , had previously held the position from 2014-19.

The Browns said in a statement Tuesday morning they were saddened by the dog's passing, though they did not release a cause of death.

As for how they'll proceed with the position going forward ... it's anyone's guess at this point -- whether PETA likes it or not.