From ANIMAL PEOPLE, September 2005:
Before there could be a successful no-kill movement, the
techniques of combating pet overpopulation without high-volume
killing had to be perfected.
The basic components were high-volume, low-cost dog and cat
sterilization; neuter/return, to help keep dogs and cats at large
from breeding back up to the carrying capacity of their habitat as
their numbers decline; and high-volume adoption, to find homes for
the animals who still come to shelters or can be removed from feral
The standard dog and cat sterilization surgeries were
approved by the American Veterinary Medical Association in 1923, but
did not become affordable for most pet-keepers until Friends of
Animals in 1957 opened the first low-cost sterilization clinic in the
U.S., at Neptune, New Jersey.
Watching from across the Hudson River, the American SPCA in
1968 began sterilizing animals before adoption. Mercy Crusade, of
Los Angeles, in 1973 opened a similar clinic that a year later would
host the first city-subsidized sterilization program in the U.S.
Working for that clinic, Marvin Mackie, DVM, developed