But during elections, which will come to this state, Haryana, and to Maharashtra on Wednesday, the fight to protect cows and the rumors about their mistreatment have ramped up. There are no reliable estimates of cow killings, so it is difficult to say whether they have increased, never mind to determine the religion of the perpetrators. But that has not stopped right-wing political parties, which have whipped up their base by demanding stricter enforcement of laws against killing cows, and some say that local activists working in tandem with those parties are exploiting religious divides for electoral gain.

Some analysts in India worry that the emergence of Narendra Modi, a hero of the Hindu right, as prime minister has emboldened religious conservatives to embark on sometimes violent campaigns against Muslims, though Mr. Modi himself has steered clear of religious issues.

One such conservative in the northern Indian state of Haryana is Mahinder Pal Singh, who runs a cow shelter. He said he mobilized his network of young men if he so much as heard of a Muslim driving a car late at night that he suspected contained smuggled cows. The work can be deadly: One of his associates was killed six months ago on a midnight raid, he said.

“We’ll catch hold of them, even if our workers are killed,” said Mr. Singh, standing at the shelter’s troughs, where dozens of cows fed and the air was thick with the smell of droppings.

In a nationally televised speech this month, Mohan Bhagwat, the leader of the Hindu nationalist organization Rashtriya Swayamsevak Sangh, urged on grass-roots activists. In the state of Maharashtra, a mob objecting to a temporary slaughterhouse set up for the Muslim holiday of Eid al-Adha earlier this month besieged a train and pelted the police with stones.