Written by Dr. Jay Kirkpatrick in response to articles in the Bucks
County Courier Times in January, 2007
[There were] two recent articles regarding wildlife contraception, by
Jeanne Bray and Jerry Feaser of the PA Game Commission which appeared in
the Bucks County Courier Times on January 15. Dr. Kirkpatrick responded
At the outset, I would like to make two points clear. First, I do
not advocate the use of contraception for deer, at Tyler Park or
anywhere else. I merely convey facts, data, and
scientifically-supported conclusions. Urban and suburban deer
problems are local issues and it is not my domain to advocate any
management approach outside my home city here in Billings. The
Tyler deer are someone else’s deer and someone else is responsible for
decisions about their management. Second, I do not deal in opinions. I
deal only in facts, derived from controlled studies, appropriate
analysis and peer-reviewed published data. With that stated, let’s
examine the article’s salient points.
To begin with, “sterilization” is an inaccurate and misleading term.
Contraception, which is what the debate is all about, is reversible
fertility inhibition, but not sterilization. Spaying is
sterilization; neutering is sterilization, but condoms, pills,
diaphragms, IUDs, and immunocontraception (vaccines) are reversible and
by definition, contraception. The paper’s editors, and both
authors should be more careful about their use of inaccurate terms.
Mr. Feaser’s letter is a masterpiece of hyperbole, misinformation and
dissembling. First, he makes no distinction between urban/suburban deer
and rural deer and the contraceptive technology, which was developed
only for deer herds where traditional management methods are not deemed
legal, wise, safe or publicly acceptable. The failure to make this clear
at the outset pits the hunting community against the broad concept of
management by contraception.
Second, Mr. Feaser contends that “...the agency have maintained a
consistent effort to reduce deer populations with hunting and
non-hunting options.” We all understand hunting, but I, at least, am
unaware of the non-hunting efforts to reduce deer populations. He had
every right to make this assertion, but then should be compelled to
explain what those non-hunting efforts are.
Next he states “Recent research has concluded that it is unlikely that
using current sterilization [sic] methods alone will reduce the
free-ranging deer population that exists throughout Pennsylvania,
including lower Bucks County.” This sentence is filled with hyperbole
and distractions from the issues at hand. First, he continues to
label reversible contraception as “sterilization” and that is really not
a terribly complex construct.
Second, he once again mixes the
rural deer population of all of Pennsylvania and Bucks County with
discrete urban/suburban populations, apparently in an attempt to
mislead. At no time, at no venue, have I or any other scientist
involved in wildlife contraception suggested that contraception (or
sterilization!) could solve “Pennsylvania’s or Bucks County’s deer
population” problems. The technology in question was
developed for discrete urban/suburban populations where traditional
lethal methods are not deemed legal, wise, safe or publicly acceptable.
Second, he cites no references for this “research”. I, on the other
hand, will be happy to cite the results of actual research. Naugle
at al. 2002. Reproduction (Suppl. 60): 143-153 reports on a deer
contraceptive project being conducted on Fire ISland National Seashore
(FINS), for the National Park Service. There are about 15
communities interspersed along the National Seashore’s 30 mile length
and thus far immunocontraception has reduced the population by
approximately 60%. That’s not an opinion. That’s fact.
So that I may not be accused of hyperbole too, let me make it clear here
that contraception is not a good way to quickly reduce a population of
deer, or any long-lived species. It can achieve zero population
growth relatively fast but it takes some time to actually reduce the
population, but it can - and has - been done.
Next, one might go
read Rutberg et al. 2004. Biological Conservation 116:243-250.
This peer-reviewed paper describes a deer contraceptive project being
conducted for the U. S. Department of Commerce’s National Institute of
Standards and Technology, in Gaithersburg, MD. This population of deer
has been reduced by approximately 40% through the exclusive use of
contraception. I could cite several other papers but these will
suffice for now. Incidentally, although it hasn’t been published
yet, the Gaithersburg data also indicates a decrease in deer-car
collisions coincident with the reduction in deer population as a result
There have been many other deer contraceptive projects, conducted by
other government agencies (USDA) and academic institutions and
proprietary companies, but none have been conducted longitudinally, over
long periods of time, and at the population level. These other
studies have tested safety, efficacy, and so forth, but not population
effects. Now Mr. Feaser next moves on the foil that most opponents use
to discredit deer contraception. He states that “...FDA has not
ruled the drugs safe and effective for wildlife...” and that they have
to be used “experimentally”.
That is true as far as it goes, but
Mr. Feaser fails to tell the entire story, and in doing this
misrepresents what is actually going on. At least at present FDA is the
regulatory authority for wildlife contraceptives (that responsibility
will be shifted to the EPA, probably within the next 12 months).
The usual procedure for the development of a new drug within FDA is to
generate “pilot” data, which provides some reasonable but no ultimate
data regarding safety and then apply for something referred to as an
Investigational New Animal Drug (INAD) exemption. This document,
which exists for the immunocontraceptive in question here, “authorizes”
the use of the drug by the FDA, in experimental settings. This is almost
exactly what takes place with new cancer drugs for humans.
Relatively few cancer drugs utilized for human medicine are FDA
“approved” but rather they are used “experimentally”. Thus,
the FDA has deemed the immunocontraceptive in question as safe enough to
use experimentally and we use it under FDA authorization.
second step for the development of a commercial drug is, if no problems
emerge from the use under the INAD, to move from an INAD to something
known as an New Animal Drug Application (NADA). This step requires
millions of dollars and many many years of additional research. We
have never taken this step, for several reasons.
First, there is
no promise of financial return for a wildlife contraceptive. The market
is just too small, thus the investment of millions of dollars just won’t
happen. Second, it was our philosophy that because most of the
research on this immunocontraceptive (something known as porcine zona
pellucida vaccine, or PZP) was originally funded with public money, over
35 years, the outcome of that research already belongs to the public and
should not be used to generate profit for a proprietary company.
That is a private philosophy, common to our research group and certainly
not a universal attitude among scientists. In any case, we took
steps to make sure the native PZP cannot be patented for use in wildlife
and continue to use it under the FDA INAD. That is a far cry from Mr.
Feaser’s gaunt description.
Now let’s add to that, that this vaccine has been around for about 35
years and much of the research focused on human contraception. It
never made it to that market because (1) no one has been able to
synthesize the product; it must be laboriously produced by what we
refer to as “bench chemistry” on a very small scale. The failure
to produce a synthetic form of the vaccine meant that a large human
market could never be serviced. We labor here to manufacture about
5,000 doses a year. The second reason it never made it to the
human market was the variability in the time for the antifertility
effects to reverse. We see that all the time, in wild horses and
deer and about 100 species of zoo animals that are currently under
treatment. All the pharmaceutical companies could see was litigation. Neither of those constraints represent a safety issue, after 35 years.
Let’s examine the safety issue just a little bit more. The vaccine
has been used on the wild horses of Assateague Island National Seashore,
in Maryland, for 18 years now, and what safety issues have arisen?
Well, first, the body condition scores of the population have increased
significantly (see Turner and Kirkpatrick. 2002. Reproduction. (Suppl.
60):187-195), mortality has decreased significantly (same paper), the
vaccine has proven to be safe to give to pregnant animals (see
Kirkpatrick et al. 1991. J. Reprod. Fert. (Suppl. 44) 321-325), doesn’t
cause changes in seasonal birth patterns or the health of foals born to
treated mothers (see Kirklpatrick et al. J. Appl. Anim. Welfare Sci.
6:301-308) and has extended the longevity of the treated horses by more
than 10 years (see Kirkpatrick and Turner 2002. J. Reprod. Fert. (Suppl.
60): 197-202; Kirkpatrick and Turner 2007. Zoo Biol. 25:1-8), nor have
any behavioral changes been noted (see Powell 1999. J. Appl. Anim.
Welfare Sci. 2:321-335) nor have there been any deleterious
physiological changes regarding the ovary or endocrine system (see
Kirkpatrick et al. 1995. Biol. Reprod. Monograph Series I: Equine
Reproduction VI: 411-418; Powell and Monfort 2001. J. Appl. Anim.
Welfare Sci. 4:271-284) I could go on, and cite dozens of other
papers regarding the use and safety of this vaccine in other species
(some 50 of them, including a lot of primates) but I think the point is
Finally, the vaccine is a protein and ninth grade biology students
who are paying attention in class know that proteins can’t pass through
the food chain. Does this all sound unsafe?
This explanation is a far cry from Mr. Feaser’s attempt to use a sound
byte, but that is what is necessary if we are to truly understand what
is going on. While I must live with sound bytes and slogans from
my politicians, I don’t intend to accept that form of discourse in the
scientific world. Let’s move on.
Next. Mr. Feaser tackles the economic dimensions of deer contraception.
He quotes a figure of $1,000 per deer. The cost of the vaccine is
$21/dose (we, by law, must provide it at our cost of production, with no
profit), the dart costs about $1.50, and the bulk of the labor to do the
darting is where the real cost lies. Costs will vary from site to
site, depending on who is doing the work and what they are paid.
If you want to pay someone $80,000 a year to dart deer, the cost will be
high; if you want to use trained volunteers the cost is less; if
you use employees already employed by a park, or agency, or whatever,
the cost is somewhere between. I actually can’t say what the costs
would be in any given site because of these variables, but I kept the
books for the first two years of the Fire Island project and the costs
never exceeded $10,000. That included a two or three air fares
from Ohio and Montana to New York, and we treated about 150 deer.
My math shows that to come out to about $66/deer. I wonder who
estimated the $1,000 per deer.
Now Mr. Feaser goes on to say that “Research also suggests that the use
of hunting alone or in combination with other management actions, may be
the only way to effectively reduce free-ranging deer populations”. If
Mr. Feaser is talking about the deer in Potter County, or even all of
Bucks County, I might agree, but we are not talking about the deer in
Potter County or all of Bucks County. we are still talking about
discrete urban/suburban deer populations. This is one more attempt to
confuse the issues. And, if Mr. Feaser bothers to read the papers cited
above, he knows that his statement is not factual.
He closes with descriptions of deer contraception as unproven (not
accurate- see above), experimental (true, see above) and cost
prohibitive (not accurate, see above). I am not dismayed by the passion
that accompanies this subject, nor am I dismayed if a community chooses
not to use contraception. That is local business and not mine.
What does upset me, is knowingly manipulating information, hyperbole,
attempts to frighten people with skewed information and an
anti-intellectual approach to debates that excludes facts and data and
substitute opinion. Does any of that sound familiar on a larger
Incidentally, lest anyone attempts to pigeonhole me in some social
activist group, I have hunted deer for most of my life and I started in
Bucks County more than 50 years ago.
You have my permission to share this response with anyone, but I
certainly believe the editorial board of the newspaper in question
should be required to see in just what kind of journalism they are
Jay F. Kirkpatrick, Ph.D., Director,The Science and Conservation
Center, 2100 South Shiloh Road, Billings, MT 59106, 406-652-9719