Have you ever owned a pit bull?  They are sweet dogs, but they get really big.
Yes, I actually have two American Pit Bull Terriers!
Pit bull
yes, these are the dogs which were used in blood sports, that are now banned
Do you know how much they weigh?
Quite a bit, I suppose. Since they have very strong physical characteristics!
Why were the blood sports banned?
Because they were sports that involved bloodshed, and were cruel to animals. 
What does that have to do with them being banned?
Since, it involved cruelty to animals and animal abuse.
When were they outlawed?