A spokeswoman for a San Francisco zoo “watchdog” group said two recent animal deaths there resulted from inadequate veterinary staffing levels. Dr. Craig Machado, the zoo’s only full-time vet, admitted the zoo would be better off with another full-time animal doctor, but denied suggestions that his schedule played a part in the deaths of a wolf and a cheetah. Sandra Keller of Citizens for a Better Zoo said the animals might have survived if Machado had been available on his day off. Keller said other zoo workers contacted her to complain about the sick animals. The cheetah died of complications after kidney failure, and the wolf was humanely destroyed because of a severe back infection and maggot infestation. Machado, however, said he checked on both animals regularly and that every medical action had been taken. He added that both animals were quite old and were suffering from natural conditions that usually prove fatal in captivity.