Blacky was jailed for biting and kicking two men near a ranch outside Tuxtla Gutierrez, the capital of Chiapas state.
Officials freed the donkey after its owner paid a fine of US$36 (euro23) and the US$115 (euro73) hospital bill of the men, who suffered bites to the chest and a broken ankle. Authorities say he also must pay US$480 (euro305) to each man for missed work days.