Selected Articles from our
The C.A.S.H. Courier
ARTICLE from the Fall 2009 Issue
Immunocontraception For Deer Works!
BY PETER MULLER, V.P. C.A.S.H.
Immunocontraception is a method used to reduce fawn-production by the
does of a deer-herd by vaccinating some of them with an agent that will
temporarily prevent them from becoming pregnant.
In combination with the
normal die-off, this reduces the herd- size without resorting to lethal
methods. The most commonly considered and currently used immunocontraceptive
products are PZP and GonaCon. PZP (Porcine Zona Pellucida Vaccine) is the
original product: it was discovered 37 years ago by Alex Shivers, at the
University of Tennessee. It is currently being further developed by Dr. Jay
Kirkpatrick. It is produced and distributed by The Science and Conservation
Center in Billings, MT.
GonaCon was developed by the USDA arid is permitted
for restricted use by the EPA. Both products are effective for reducing deer
densities in enclosed parks and urban settings. PZP requires two
applications for optimum efficacy and GonaCan claims efficacy with just one
That difference is not significant since, as Dr. Kirkpatrick
points out, after the first year each application of PZP is effective with
Immunocontraception is not a really “new technique”; It has been
successfully used for wildlife since the late 1980s. The most accurate
objective judgment of the efficacy of this method is simply “It works.”
So this article could end right here if it were not for some economic,
political and sociological interests who do not want to see
immunocontraception used. The interest groups who argue against its use are
the usual gang of suspects:
Ø Hunting groups fear that it will reduce local governments’ tendency to
buy into their claim that only hunting can control urban deer populations in
areas where the deer density is above the social carrying capacity.
Ø The DNRs (the state environmental conservation agencies) anticipate that
using immunocontraception will accelerate the current steady decline of
hunting license sales. They fear a steep loss of revenue to their wildlife
management departments, which are currently primarily funded, directly and
indirectly, through the sale of hunting licenses.
Ø One federal agency relies on a source of income by functioning as an
extermination service of “nuisance animals” to farmers, ranchers, and
municipalities. They also fear a loss of revenue and quite possibly raising
the more fundamental question: “Is there a need for that service by the
federal agency government in the first place?”
As we look at their objections, let’s keep in mind the old saying: “It’s
hard for a man to understand an argument if his livelihood depends on not
The most commonly heard objections to the use of immunocontraception are:
Ø It doesn’t work
Ø It’s experimental
Ø It causes genetic or biologically debilitating harm to the target species
or other species.
Ø It’s too expensive
It doesn’t work
The first argument seems false on the face of it. Many published and peer-
reviewed cases in the scientific literature show that it does, in fact,
work. Immunocontraception reduces the size of a given deer herd by
decreasing the number of fawns born in spring. If after the normal fawn
mortality the herd-size before the next rut is less than the herd-size prior
to the rut at the time that immunocontraception was administered the herd
size has been reduced. So it does work
Decline in deer density since 1995 at Fire Island Used
with permission of copyright holder: The Science and Conservation Center in
A common secondary objection tagged on this one is: if the target area is
contiguous to other areas where the does have not been treated - deer from
those adjoining areas, where the deer density is now higher, will migrate
into the target area and re-establish the original density. This is true -
but, of course, that would happen no matter how the reduction of the
deer-size is achieved. It is not an argument against using
immunocontraception but, rather, an argument for using a coordinated effort
of immunocontraception in wider areas.
Decline in does fawning since 1993 at Fire Island Used
with permission of copyright holder: The Science and Conservation Center in
In the layman’s terms “experimental” equates to words such as “untried,”
provisional” or “tentative:” Experimental as used by the FDA in describing
the status of a medication means that it is not approved for commercial
sale. Since the manufacturer of PZP, the originator of immunocontraception,
has never applied to sell it commercially, it remains in “experimental”
status. It is authorized for use with certain reporting requirements
attached: it is in the same category as most medication used to treat
This argument is simply a ruse: it uses a technical term, which has negative
cognates in everyday English, to scare the public and technically
unsophisticated local government decision-makers.
It causes genetic or biologically debilitating harm to the target species
or other species
The allegation is that for various reason harm may be caused to the target
animals or to other animals or people who are ingesting the meat of an
animal that has been treated with immunocontraception. Basic biology assures
us that the agent, which is a protein, cannot be passed on through the food
There was some early speculation that since the normal cycle of does
going into estrus every thirty days is extended for two more cycles (ending
in February/March instead of December/January) it might have a debilitating
effect on the does or on the bucks servicing them. Empirical observation of
has shown no evidence of that. It also has shown no significant change in
social behavior. No substantial, empirically verifiable debilitating effect
has been found in over 20 years of application.
It’s too expensive
The cost figure is the easiest argument for the opponents of the use of
immunocontraception to put forth and the most effective, when aimed at
legislative bodies such as city councils, town or village boards and county
legislatures who are sensitive to not approving exorbitantly priced
The usually alleged price per doe vaccinated is estimated to be
between $500 and $1,000. For a municipality seeking to reduce the urban
herd-size by vaccinating 100 animals with an immunocontraceptive agent -
that would come to $50,000 to $100.000; which represents a significant part
of its budget. That putative price tag is much higher than a realistic
estimate would lead us to.
There are two price components in each vaccination:
1) the cost of the dose
2) the cost of delivering the dose
a. the labor
b. cost of a delivery system
The cost per dose of PZP is about $30/dose.
Labor cost is about $15/hour
The time it takes to dart a deer varies greatly depending on the deer
density of the region and some other factors. In a study by Allen Rutberg
(Humane Wildlife Solutions published by Humane Society Press) the lime it
takes to dart a deer ranges from 1 hour up to 17 hours. The 17 hour time was
definitely a statistical outlier hat should probably be ignored. A
conservatively high value to work with seems to be around 4 hours, which
would make it $60 per deer vaccinated.
The delivery system (a dart shooting rifle) is about $1,000 -$3,000; again
taking the higher number, to be conservative, and amortizing the cost of the
weapon over 500 deer the delivery system cost per vaccinated deer is $6.
Assuming we are in a park system where we would use the same workers to do
the darting year after year - it would pay to send them for training which
is $200 per trainee plus an estimated $1,000 additional for travel and
lodging. Estimating each shooter’s lifetime darting output at 200 deer (four
years at 25 days with two deer darted per day) brings the amortized training
cost borne by each darted deer to $6.
The total cost comes to $102 per deer. Darting 100 deer each year brings the
total cost for the municipality’s deer control program to $10,200 per year.
There is simply no reasonable assumption that will get the price per deer
darted from $102 to $500 much less to $1,000
The EPA, in its protocol for applying GonaCon, insists that the deer may
not be darted. It must be captured, restrained and injected by hypodermic
needle. That requirement, which has no apparent scientific basis, is highly
labor-intensive and can make the cost per deer vaccinated approach the $500
A reasonable estimate of the cost of immunizing a deer is
around $100 per deer - it can vary from $60 per deer to $250 per deer
depending on the deer density of the region and other factors. Without
requiring capture, restraint, and inoculation by hypodermic needle there is
no rational way to get that number up to or over $500 per deer vaccinated.
The opponents of immunocontraception don’t really have a case -- know the
facts and present them at your next local public hearing session that seeks
to permit bow-hunting in your local parks.
Go on to Next Article
Back to Fall 2009 Issue
Back to C.A.S.H. Courier Article Archive