The trouble was triggered after the severed head of the calf was found by locals near the market place in Lohaghat, Sub-Divisional Magistrate RC Gautam said.
The slogan-shouting mob, led by Hindu organisations and local BJP MLA Puran Phartiyal, poured into the streets and forced closure of the entire local market, he said.
People in thousands gathered in the market, shouted slogans against the killers and demanded that an inquiry be immediately ordered into the incident.
The mob has demanded that the meat market of the town be closed till the completion of the inquiry into the matter, the SDM said.
It looks like the handiwork of miscreants who wanted to disturb peace of this quiet town, he said.
An FIR was lodged against unknown people in connection with the incident, he said, adding the situation was under control.