Cows are sacred to India’s Hindu majority. For Muslims who trade cattle, that means growing trouble.

MAHABAN, India — In the year since an extremist Hindu monk was tapped to lead one of India’s biggest states, the country’s Muslim cattle traders have seen their lives change in ways they could not have imagined.

First mobs of Hindu vigilantes emboldened by the monk’s victory began swarming buffalo trucks on the road, intent on finding smugglers illegally transporting cows, which are sacred to the Hindu faith and protected from slaughter in many places in India. Some Muslim men were killed by lynch mobs, as recently as June 18.