Overpopulation of cats and
dogs has been a problem around the world for decades. Differences of opinion about controlling roaming
and sterilization, as well as urban population explosions have all contributed
to the growing numbers of reproducing stray dogs and cats. Surgical sterilization of females using
ovariohysterectomy (spay) or of males using castration (neuter) have been
promoted and utilized in attempts to control unwanted litters as well as
community overpopulation. True cost of
these procedures has been subsidized by private veterinarians for years, or
completed at spay/neuter clinics in an assembly line fashion, all in an attempt
to reduce reproducing adult numbers in our communities. In some regions, this has had a profound
impact, but many regions are hopelessly outnumbered and unable to make a
sustainable dent in the populations. The
cost of these programs is considerable, making pragmatic efforts difficult.
There is no shortage of
proposed solutions to this problem.
Veterinarians from TuftsUniversity’s Cummings School of Veterinary Medicine have offered a different
perspective on the issue, proposing vasectomies and hysterectomies may be
superior because of the downward effect on reproduction rates seen in the
preservation of hormonally driven behavior in a population.
“Sex drive and social status
would remain intact, allowing males to protect turf from other feral males,
ward off new strays, and compete for females, which go into a prolonged state
of “nonreceptive” pseudo-pregnancy after sexual activity. Females likewise
continue to compete with sexually functional females. The result: fewer
successful matings, the researchers conclude.”
While more information and
data is certainly needed, some have argued that simply vasectomizing may not
offer the solution. The Alliance forContraception in Dogs and Cats has been searching for a permanent non-surgical sterilization solution for 14 years.
The ACC+D, founded in 2000
out of Auburn University, proposes non-surgical solutions would be potentially
less expensive, and easier to administer, issues key to the success of the
future of population control. They
propose the following priorities:
Priorities for
Non-Surgical Products for Pet Population Control
- Approved by regulatory agencies as safe (for animals and for the humans administering) and effective.
- Permanent, though there may be some opportunity for long-term (3+ years) products.
- Deliverable in a single injection or treatment.
- Products available for effective use in both male and female, dogs and cats. Documented effects on behavior and health.
- Can be provided at affordable rates for use in indigent or low-income client populations.
An Ontario
Veterinary College researcher has received a $260,000 grant in support of
research aimed at developing an inexpensive, non-surgical alternative for
sterilizing shelter animals.
Based out of Bragg
Creek, Alberta veterinarian, Dr. Judith Samson-French has been trialing the use
of injectable ‘deslorelin’, a GnRH agonist on First Nations female dog
populations, with some success. “We have
been importing the drug, routinely used in Australia, using the Emergency Drug
Release program,” she said. Dr. Samson-French has
been observing sterility for approximately 3 years. “We need to go after the females” expanding
that to impact a population through sterilization of the males, likely requires
over 90% of the population to be sterilized."
Zeuterin™ (U.S.) is a
product developed to permanently chemically sterilize male dogs through a
process called "zinc neutering." It is marketed outside the U.S. under the label EsterilSol™. This intratesticular injection is effective,
but has adverse reactions such as swelling, redness and irritation and requires anti-inflammatory pain killers, creating a logistical problem to administer in
free roaming dog populations.
Dr. Samson-French feels we
are ten years away from a permanent non-surgical injectable sterilization
product for females, citing not only the lack of a current available product,
but an expensive, lengthy and arduous regulatory approvals process.
Veterinary specialist Dr.
Julie Levy, Maddie’s® Professor of Shelter Medicine
Director,
Maddie’s® Shelter Medicine Program at the University of Florida
has been studying a vaccine for GnRH, called Gonacon.
The study showed 93%
effectiveness against fertility for 1 year, and a drop to 50% efficacy in 3
years, and 27% in 5 years.
The work continues to
discover the solution to overpopulation, and research into novel innovations
such as nonsurgical contraception provides hope for the Animal Industry and
communities around the world.
Dr. Drew Van Niekerk celebrates more than 20 years in the Urban Animal Industry as a practicing veterinarian in Calgary, Alberta and a long-standing board member of the Calgary Humane Society. Drew is also a staunch supporter of Urban Animal Program events and the initiatives and conversations that arise from them.
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