midnight
`` It was strictly a milk run , '' Major Quartermain was quoted as saying as he emerged from his ship after an uneventful but propaganda-loaded trip . By the middle of May , it was the consensus of the veterinarians that Delivery Day would be July 4th . Plans were drafted for the repeat atomic cave shot at 9:00 p.m. , July 3rd . The pregnant herd was to be given labor-inducing shots at midnight , and , if all went well , deliveries would start within a few hours . Just to be sure that nothing would shield the cows from the rays of the explosion , they were put in a corral on the south side of the barn until 9:30 p.m. , on the night of the firing . Solomon 's successor and a new bevy of hens were already roosting in the same old chicken house and egg production was normal . On the night of July 3rd , at precisely 9:00 p.m. , a sheet of light erupted from the Nevada hillside cave and the ground shook and rumbled for a few miles .