The video was obtained by KXXV News Channel 25 in Waco, Texas, and captures Zamora hitting a dog eight times with a belt and kicking it while yelling.
"I lost my temper trying to discipline him," Zamora told KXXV in a statement. "I've been through training with a dog trainer to help me learn new potty training tips."
The incident was recorded and posted on Snapchat by a teammate in late June, according to KXXV.
A former Baylor student saw the video and reported it to authorities. Zamora was charged with a Class C misdemeanor and received a citation for up to $500 for the incident.
Baylor interim coach Jim Grobe told reporters Zamora will be disciplined and that his playing status will "probably" be affected.
"I think he's going to be disciplined by a bunch of people -- the city is gonna get a piece of him, and our university doesn't take it lightly," Grobe said. "There will be some sanctions from the university and, from an athletic department standpoint, we'll do some things. But hopefully it's a teaching moment and a learning experience for him."
Zamora, a sophomore, caught nine passes for 132 yards and two touchdowns last year and is projected to be a starter for the Bears this season.
Grobe called Zamora's situation "an ongoing thing" and said the staff already knew about the incident and would not tolerate it.
"I think he just was frustrated and spanked his dog for not being house-trained, and you just can't do that," Grobe said. "He knows that. He loves the dog and takes great care of the dog, other than, you know, losing his temper with the dog. I think he's taken pretty good care of him."