Still no injectable birth control for dogs and cats

From ANIMAL PEOPLE, October 1998:

Hopes for an inexpensive injection
sterilant for dogs and cats were prematurely
raised worldwide in early September by a
CNN report about an experimental contraceptive
vaccine for female rodents developed by
California researcher Jeff Bleil.
In theory, the Bleil vaccine could
work in dogs and cats, as CNN noted, but
Bleil so far has tested it only in mice and rats,
and he is reportedly still at least two years
from being able to market it for laboratory
mouse population control, his first objective.
He apparently hasn’t begun work yet to adapt
the product for use with other animals.
Zonagen Inc., of Massachusetts,
announced in 1990, 1991 and 1994 that it had
almost perfected a similar contraceptive vaccine,
called Zonavax, for female dogs and
cats, but there has been no further word of it.

Proteus International, of Britain,
announced in 1994 that it was working on a
contraceptive vaccine for male dogs and cats.
Janssen Pharmaceuticals was testing the product
in Belgium as of August 1997, but the
emphasis seemed to have shifted to applications
for farm animals. ML Laboratories, of
Britiain, was in August 1997 testing the same
vaccine as a possible treatment for prostate
cancer in male humans.
Neutrosol, a zinc arginine-based
injection sterilant for male dogs, has been
tested in Mexico by Mostafa Fahim of the
University of Missouri and Hugh Wheir,
DVM, since January 1994. The Arizona
Humane Society and the North Shore Animal
League are now also testing it.
Neutrosol is the injection sterilant
believed to be closest to availability, but––
though Fahim has published papers about
progress in developing it since 1982––it is still
at least three years away from mass production.
Before Neutrosol is licensed for broader
use, the handful of dogs who have received
the injections so far must be observed for
some time yet to observe possible side effects.
The Humane Society of the U.S.
partially sponsored trials of both Zonavax and
Neutrosol in the early 1990s, but in April
1991 was attacked in print by Friends of
Animals because the work then involved
killing and dissecting cats to do a cancer assay
which was at that time required by federal law.
Congress in August 1996 repealed
the law, but HSUS involvement in the
Zonavax and Neutrosol projects had apparently
already ended. HSUS continues to sponsor
research on contraceptive vaccines for deer
and wild horses. Field tests of these vaccines
have been underway for several years.
The first flurry of hope for a cheap
injectable or implantable dog and cat sterilant
came with the introduction of a hormonal drug
called Ovaban nearly 30 years ago, now widely
used abroad but not registered for animal
birth control use in the U.S. due to side effects.
It is sold in the U.S. for other purposes.
Carnation Inc. test-marketed a contraceptive
dog food circa 1981, to be sold by
veterinarians through prescription, but soon
withdrew it amid allegations that humans
could eat it to produce abortion.
In India, the National Institute of
Immunology developed a zinc tannate injection
sterilant for male animals in 1988, called
Talsur. It was used experimentally in 1990-
1991 to control populations of street dogs.
However, after at least 22% of the dogs developed
complications from the injections, the
Talsur project was discontinued.
University of Western Ontario professor
John P. Weibe in 1988 patented an
injectable sterilant based on a chemical called
trihydroxypropane. Weide said he had tested
it on rats, rabbits, and monkeys––but not on
dogs or cats, and his intent, reportedly, was
to produce a contraceptive for male humans.