MAZAR-I-SHARIF, Afghanistan — A boy about 8 years old, sitting cross-legged on the cab of a truck, shouted at the top of his lungs: “Go John Cena, go boy, give it to him, I want to take all your pain on myself!”

John Cena in this case was not the American professional wrestler but a mangy, tawny shepherd dog who at that moment had his head stuck in the jaws of a rival in a blood-spattered fight, one of 13 held in a stadium on a single day late last month as part of Nowruz, or Persian New Year festivities.

John Cena shook his head free and in a frenzy ripped into his foe, a dog named German, until the judge declared a winner and their handlers pulled them apart.

Unlike dogfighting in most other countries, these matches were being held openly, with little fear of prosecution. In fact, a policeman named Ahmad Fawad was on duty, wielding a big stick in a not-always successful effort to keep the two-legged animals under control.