Three security guards on the night duty have been suspended, they said.
Kanpur Zoo director K Praveen Rao said that during the morning inspection of the enclosure, 31 blackbucks were found killed with some wild dogs still eating from their remains despite the presence of barbed wires around it.
The dogs were immediately driven away and two of them were shot dead in the process by the guards.
Out of the 38 blackbucks inside the enclosure, seven have survived, Rao said.
The post-mortem of the dead blackbucks have been conducted and an investigation team has been constituted to probe as to how the dogs managed to enter the enclosure despite the presence of the barbed wires, Rao said.
The security guards have been suspended for dereliction of duty, he added.