The incident occurred early in the morning when the Park staff was asleep.
Among the killed were 25 female and 4 male antelopes. There were 34 blackbucks in the single enclosure, said a Park officials.
The police is probing the incident.
Blackbuck, which is included in the Schedule 1 of the Wildlife(Prevention) Act, is the state animal of Punjab.
Several Blackbucks have died in the Park in past due to tuberculosis. PTI Corr PL