There's a similar "sport" going on called "hot dogging" involving dogs and pigs.
The people involved state they are "training" the dogs for hunting wild boar, but, like in the video the pigs are set in pens, have at times been chained and are sometimes injured prior to the dogs being unleashed.
The pigs/boars have had their tusks filed down so they don't injure the dogs. Their abilities to defend themselves are greatly diminished.
Now, I'm a hunter (not some left-wing PETA activist) and I'm all for hunting, when it's done for the right reasons (ie; food) but I'll take my game fairly, not like this.
This isn't a sport, it's cruelty.