Study Proposal
Effects of chronic wasting disease on the fecundity on female mule deer
(from birth to weaning)
Jessie R. Dulberger
Graduate Degree Program in Ecology
Colorado State University
Dr. N. Thompson Hobbs
Natural Resource Ecology Laboratory
Colorado State University
Dr. Michael W. Miller
Colorado Division of Wildlife
Graduate Degree Program in Ecology
Colorado State University
Dr. Michael F. Antolin
Professor and Assistant Chair
Department of Biology
Colorado State University
Project Summary
The goal of this study is to understand how much chronic wasting disease affects
fecundity on female mule deer. The study will be conducted in a non-hunted natural
area in the foothills of Boulder, Colorado. Our objectives of this study are to
compare fecundity (i.e., potential reproductive capacity) rates for chronic wasting
disease infected and non-infected female deer during the first month of birth and
during weaning in the 3 month of birth. In order to meet these goals we will observe
forty-two radio-collared does and assess fawn presence or absence for three
summers after parturition (in June) and during weaning (in August). Twice a week
each animal will be monitored for mortality. Initial results from the pilot study
suggest that the fecundity of chronic wasting disease infected does is much lower
than non-infected does. This study is unique because the mule deer population is
not affected by hunting.
Introduction
Chronic wasting disease (CWD) is a natural, infectious and fatal prion disease that
negatively affects members of the deer family, mainly Mule Deer (Odocoileus
hemionus), Elk (Cervus elaphus nelsoni), and White-Tailed Deer (Odocoileus virginianus
(Miller et al. 2005). CWD causes neural degeneration and ultimately death (Williams et
al. 2002, Hobbs et al. 2002). Wildlife managers in many states with wildlife recreation
based economies are concerned about the possible devastating effect of chronic wasting
disease on the state’s deer populations. Population models suggest that fawn survival is
key to maintaining deer population dynamics (Jensen et al. 1999).
We hypothesize that chronic wasting disease does have a significant affect on fecundity
in female mule deer.
Objectives
Important factors that affect the stability of a healthy deer population is the fecundity of
does and fawn recruitment (Pojar and Bowden 2004). Therefore it is important to study
how CWD affects both the fecundity and fawn recruitment up to weaning, in a freeranging mule deer population.
The specific objectives of this study are to:
(1) Compare the presence or absence of fawns during the neonatal period with
infected vs. uninfected does.
(2) Compare fawn survival of infected vs. uninfected does until weaning (16 weeks
after birth.
(3) Compare presence or absence of fawns of captive infected and non-infected
female mule deer fecundity (Colorado Division of Wildlife unpublished data).
Background
In the last 39 years, CWD has become a threat to states with wildlife recreationbased economies and thus a concern to both the public and wildlife managers throughout
the country (Miller 2002, Williams et al. 2002, and Hobbs et al. 2001). Currently CWD
is not a direct threat to humans. There have been no cases of human prion disease
associated with CWD (World Health Organization 2000, Belay et al. 2001), but a recent
study has shown that CWD specific prions ( PrPres) are in skeletal muscles. This raises
the possibly that through consumption of infected cervid meat, dietary exposure to prions
could occur (Angers et al. 2006). The disease is thought to be transmitted indirectly to
deer horizontally via prions in feces (Miller et al. 2004), but a recent study with captive
deer has shown that fawns orally given blood, saliva and chronic wasting disease infected
brain tissue, tested positive for the chronic wasting disease prions within 12 months of
age (Mathiason et al. 2006).
Models show that CWD epidemics drive populations to extinction, specifically
when prevalence rates reach 5% larger (Miller et al. 2000). The reduction of cervid
populations across North America may harm the balance within many ecosystems
(Hobbs et al. 1996). Culling deer herds in CWD hotspot areas had been the practiced
management technique, until recently. The Colorado Division of Wildlife has halted the
practice of culling, because the prevalence of CWD in deer populations has not been
reduced over the past 5 years (Colorado Division of Wildlife, unpublished report).
Further studies are needed to understand how CWD spreads, how to stop it from
spreading, and how it affects deer populations.
Declining mule deer densities have caused wildlife researchers to focus on
studying fawn survival and recruitment (Pojar and Bowden 2004). Population models for
deer suggest long-term population trends are most sensitive to the survival of fawns,
(Jensen et al. 1999). Andelt et al. 2004 showed that mule deer fawn:doe ratios in
December had declined by 0.015 fawns/doe/yr from 1972 through 1995 in Colorado.
Many hypotheses have been offered to explain fawn:doe declines including: failure to
breed, decreased fecundity, resorption/abortion of fetuses, low summer and fall fawn
survival, habitat deterioration, increased predation, drought, hunting, disease or a
combination of these factors (Unsworth et al. 1999, Andelt et al. 2004, Pojar and Bowden
2004). Andelt et al, 2004 concluded that failure to breed or maintain pregnancy through
at least early January or February was not the cause of low fawn:doe ratios observed in
Colorado, since 90-93% of deer in the study were pregnant. Predation, specifically
coyotes (Canis latrans) has been questioned as a significant mortality factor for fawn
numbers (Jensen, 1999), but it has since been shown that coyotes (Canis latrans) and
mountain lions (Felis concolor) appear to kill fawns in very poor condition (Bishop,
2005). Mortality rate of fawns were not directly related to population levels of coyotes
(Hamlin, 1984). Pojar et al. found that the highest cause of fawn mortality was
sickness/starvation, and second were coyotes. Another study showed that poor doe
condition was the primary cause of early fawn loss (Wood 1962). We hypothesis that
chronic wasting disease negatively affects does fecundity in two possible ways. We
have observations, from the main Boulder mule deer study, that does with chronic
wasting disease exhibit non-normal behavior, (not staying as close with the herd and
decreased alertness), that could be linked to bad parenting skills. We also hypothesis that
chronic wasting disease negatively affects the body condition of does. Yoakam 1965
observed that poor body condition of does led to fawn/s being born weak or handicapped,
and then death within their first week.
This study will evaluate the effects of CWD on the fecundity of adult does in the foothills
of Boulder, Colorado. An ongoing mule deer survival study with the City of Boulder’s
Open Space and Mountain Parks and the Colorado Division of Wildlife has thus far
shown a relatively high prevalence rate (50% in bucks and 30 % in does). When animals
were retested a year later 25% of the does that were not infected had contracted chronic
wasting disease (unpublished data). Models forecast population declines once CWD
prevalence exceeds about 5% (Miller 2000). Therefore the deer population along the
Front Range in the City of Boulder is in jeopardy, and will be a good example of how
CWD affects a non hunted free-ranging mule deer population.
The City of Boulder Open Space and Mountain Parks (OSMP) has had several mule deer
population studies using the Lincoln-Peterson estimator. From 1983 to 1990 there was an
increase in the mule deer population from 783 to 1,238 in a 17 square mile area (Kelsey,
1990). The study area for this past study was twice as large as the current study and it
ranged North of El dorado Springs Drive to just south of Lee Hill Road. The 2005 markresight population count of mule deer averaged 270 using the Bowden estimator. The
study area ranged North of El dorado Springs Dr. and South of Baseline Rd. Even though
the 2005 study is half the size of the study done in 1983-1990, if doubled it would only
average around 540, which is the lowest City of Boulder population seen in many years.
The Pilot Study Summer 2006
From June to September in 2006, a pilot study was conducted. The power calculation
performed from this initial data set showed that we will need twelve infected and equal
numbered non-infected does to detect a difference of 0.9 in fecundity rates. Figures 2,3
and 4 demonstrate that sample sizes of seven and ten were too small, while fifteen is not
needed. The methods during the pilot were not as rigorous as the methods will be for the
following two summers, due to lack of time. There were seven matched pairs of does in
the study for the summer of 2006. Extra non-infected does were also observed for
presence or absence of fawns, mainly in August/September, (please see figure 1.). Using
Likelihood and Akaike’s information criterion corrected for small sample bias (AICc) for
model selection, we were able to detect a difference using a two parameter comparison.
The two parameter model had more support in the data than the one parameter model.
The limiting factor for this study is the sample size of chronic wasting disease infected
does, since only one out of three female deer sampled tested positive for CWD.
Number does with
Number total does
Fawns
Observed
CWD Positive
3
7
23
32
CWD Negative
Figure 1. Pilot study data from summer 2006.
total # of does (7)
1.2
1
wr
0.8
0.6
0.4
0.2
0
0
1
2
3
4
5
6
1 parameter
2 parameters
# of does w ith faw ns
Figure 2. One versus two parameters for seven does.
Total # of does 10
1.2
1
wr
0.8
0.6
0.4
0.2
0
0
1
2
3
# of does with fawns
4
5
1 parmater
2 parmaters
Figure 3. One versus two parameters for ten does.
6
Total # of does 12
1.2
1
wr
0.8
0.6
0.4
0.2
0
0
1
2
3
4
5
# of does with fawns
6
1 parameter
2 parameters
Figure 4. One versus two parameters for twelve does.
Total # of does 15
1.2
1
wr
0.8
0.6
0.4
0.2
0
0
1
2
3
4
# of does with fawns
5
6
1 paramter
2 paramters
Figure 5. One versus two parameters for fifteen does.
Material and Methods
Study Area: The study area will focus on low-elevation mule deer winter range. The
study area in Boulder boundaries are as follows: Baselines Rd on the north, Broadway Rd
and the east, El dorado Springs Dr. on the south and the Flatiron Mountain range to the
west ( See figure 7.).
Figure 7. Study area in Boulder, Colorado
Methods
200 meters
Figure 8. Fawn search method.
Approach: Adult does have been previously marked with unique numbered ear tags and
collars with mortality-sensing radio transmitters. In May each doe’s summer fawning
locations will be located. Twelve CWD infected and twelve non-infected does will be
paired as of June 1st or last date seen in May, on the basis of infected or not infected with
chronic wasting disease, age, location and genotype. Additional non-infected does will
also be monitored the same as the paired individuals, time permitting.
The location and body condition of each doe has been determined at least once a month,
since their original capture date. They are also monitored twice weekly for survival
status. When an animal dies it is found via the mortality emitting radio transmitter and
telemetry. The cause of death is recorded and samples are taken to retest for chronic
wasting disease, and if the cause is unknown the body is submitted for a necropsy to the
Colorado Division of Wildlife laboratory.
Beginning June 1st, each doe will be observed 1x/week for two hours a day to determine
the presence or absence of fawn/s. During these observations does will be located, and
monitored from a distance far enough to avoid alerting them, but close enough to identify
the radio-collar number and udder development, (approximately 40 m) (Shively et al.
2005). If fawns are not seen during the initial two hour observation, then a fawn search
will be performed for an additional thirty to forty minutes. The search will consist of
marking the original location of the doe upon first approach and then searching out to 200
meters in a circle around that original point (see figure 8). If searches are unsuccessful,
but the doe remains in the same vicinity, a follow-up searches will made 1-2 days later,
time permitting. As fawns are located, the technician will slowly leave the area, as to not
stress the fawn. When fawns and does are seen together, fawn less than 20 meters away
will be considered associated with the doe (Schwede et al, 1994). Once the presence of
fawns is established, does will be observed twice a month until weaning when fawns are
16 weeks of age, or the end of September. At each observation the body condition,
location of the doe and fawn, presence or absence of fawn/s and vegetation type will be
recorded.
Since there are forty-two deer to observe, deer will be observed at different times to
utilize all daylight hours. There will be two technicians working on this project, therefore
eighty hours a week of observations. There will be two time shifts, to cover sunrise and
sunset, (6AM-2PM and 12PM-8PM). Does that show behavioral and physical
characteristics, such as moving alone, udder development and sunken flanks, are prime
candidates for having fawns (Pojar and Bowden 2004, Huegel et al. 1985).
During the first eight weeks after birth mothers associate very little with fawns and
periods of contact are brief, occurring predominantly around sunrise and sunset (Schede
et al. 2006). It is also crucial to detect presence or absence of fawns after in during the
neonatal period because in June the probability of survival is lowest, 0.33 in June
compared to 0.9 in September (Raganella-Pelliccioni, 2006). Mothers also keep the
shortest distances during the first two weeks (Schwede et al. 1994). During this time
does can also be approached closely before flushing (Huegel et al. 1985). Huegal et al.
1985 found that does always remained in the general vicinity of their fawns while the
crew searched.
Analysis
Conditional logistic regression will be used to evaluate the relative strength of models
predicting female fecundity. Several factors that will contribute to these models are:
location, genotype, and age and CWD status. We will create a candidate set of models
via a priori knowledge and use likelihood inference and AICc to select the model that has
the most support in the data.
We will also similarly analyze a Colorado Division of Wildlife data set of captive does
and their fecundity rates. There are several years of fecundity data with specific birth
dates and death dates of fawns, their genotypes, whether they are CWD infected or not,
and how long they have had the disease.
Budget
June 2006-September 2006
Research Assistantship ($/month * 4 monthes) (first field season)…$(OSMP)
Field Equipment (scope, digital camera, logbook, binoculars, miscellaneous)………..$2,000.00
Tom’s Salary ?
Mike’s Salary ?
1st Field Season Subtotal……………………………………………………………….$2,000.00
+ Ten Percent…………………………………………………………………………..$200.00
1st Field Season total…………………………………………………………………..$2200.00
October 2006-September 2007
Research Assistantship ($1500/month * 12 months + fringe) (first field season)……..$14,400.00
Tuition (two semesters)………………………………………………………………...$3,073.98
Field Assistant (2 monthes at $1760/month+fringe)..………………………………….$3,520.00
Materials and Supplies…………………………………………………………………$300.00
Travel and Conferences……………… ………………………………………………$500.00
Tom’s Salary ?
Mike’s Salary ?
Year 1 Subtotal……………………………………………………………………….$21,793.98
+ Ten Percent…………………………………………………………………………$2,179.39
Year 1 Total…………………………………………………………………………..$23,973.37
October 2007-September 2008
Research Assistantship ($1500/month * 12 months + fringe) (first field season)……..$14,400.00
Tuition (two semesters)………………………………………………………………...$4,810.90
Mileage (,000 miles/week at 36 cents/mile...…………………………………………..$?
Field Assistant (2 monthes @$11/hr 40hr/wk +fringe)………………………..………$3,520.00
Materials and Supplies………………………………………………………………….$300.00
Tom and Mike’s Salary ?
Year 2 Subtotal…………………………………………………………………………$23030.90
+ Ten Percent…………………………………………………………………………..$2,303.09
Year 2 Total……………………………………………………………………………$25333.99
October 2008-September 2009
Research Assistantship ($1500/month * 12 months + fringe) (first field season)……..$14,400.00
Materials and Supplies…………… ………………………………………………….$300.00
Tom and Mike’s Salary ?
Year 3 Subtotal……………………………………………………………………….$14,700.00
+ Ten Percent…………………………………………………………………………$1,470.00
Year 3 Total…………………………………………………………………………..$16170.00
3 ½ YEAR PROJECT TOTAL……………………………………………………….$63,904.27
Budget for Jessie Dulberger for 2 ½ years. 3 field seasons, 5 semesters of classes, 1 semester to write thesis.
Literature Cited:
Andelt,William F., Thamas M. Pojar, and Laurie W. Johnson, 2004. Long-term trend in
mule deer pregnancy and fetal rates in Colorado. Journal of Wildlife Management: Vol.
68, No. 3, pp. 542-549.
Angers, Rachel C., Shawn R. Browning, Tanya S. Seward, Christina J. Sigurdson,
Michael W. Miller, Edward A. Hoover and Glenn C. Telling, 2006. Prions in skeletal
muscles of deer with Chronic Wasting Disease. Sciencexpress: www.sciencexpress.org,
pp. 1-3.
Belay, Ermias D., Ryan A. Maddox, Elizabeth S. Williams, Michael W. Miller, Pierluigi
Gambetti, and Laurence B. Schonberger, 2004. Chronic wasting disease and potential
transmission to humans. Emerging Infectious Diseases: Vol. 10, No. 6, pp. 1067-1082
Bishop, Chad J., James Unsworth, and Edward Garton, 2005. Mule deer survival among
adjacent populations in Southwest Idaho. Journal of Wildlife Management: Vol. 69, No.
1, pp. 311-321.
Hamlin, Kenneth L., Shawn J. Riley, Duane Pyrah, Arnold R. Dood, and Richard J
Mackie, 1984. Relationships among mule deer fawn mortality, coyotes, and alternate
prey species during summer. Journal of Wildlife Management: Vol. 48, No. 2, pp. 489499.
Hobbs, N. Thompson. Spatial and temporal dynamics of prion disease in wildlife.
(Unpublished report)
Huegel Craig N., Robert B. Dahlgren, H. Lee Gladfelter, 1985. Use of doe behavior to
capture White-tailed deer fawns. Wildlife Society Bulletin: Vol 13, pp. 287-289.
Jensen, William F., Bruce A. Stillings, Roger W. Johnson, 1999. An evaluation of
factors influencing mule deer fawn recruitment in the North Dakota Badlands. The
Journal of Wildlife Management: Vol. , No. , pp. (from abstract, looking for journal
info)
.
Kelsey R. 1990. Lincoln-Peterson Population estimate on the deer population in Boulder,
Colorado. Unpublished report to the City of Boulder, Open Space and Mountain Parks.
Mathiason, Candace K., Jenny G. Powers, Sallie J. Dahmes, David A. Osborn, Karl V.
Miller, Robert J. Warren, Gary L. Mason, Shelia A. Hayes, Jeanette Hayes-Klug, David
M. Seelig, Margaret A. Wild, Lisa L. Wolfe, Terry R. Spraker, Michael W. Miller,
Christina J. Sigurdson, Glenn c. Telling and Edward A. Hoover, 2006. Infectious Prions
in the Saliva and Blood of Deer with Chronic Wasting Disease. Science: 314, pp. 133136.
Miller, Michael W., Elizabeth S. Williams, Craig W. McCarty, Terry R. Spraker, Terry J.
Kreeger, Catherine T. Larsen, and Tom E. Thorne, 2000. Epizoology of Chromic
Wasting Disease in free-ranging cervid in Colorado and Wyoming. Journal of Wildlife
Disease: Vol. 36, No. 4, pp. 676-690.
Miller, Michael W., Heather M. Swanson, Lisa L. Wolfe, Sherry L. Huwer, Fred
Quartarone, Bryan Pritchett, Charles H. Southwick, 2005. Effects of CWD infection on
mule deer survival and productivity: long-term implications for population performance
Study Plan.
Miller, Michael W., Elizabeth S. Williams, N. Thompson Hobbs, and Lisa L. Wolfe,
2004. Environmental sources of prion transmission in mule deer. Emerging Infectious
Diseases: Vol. 10, No. 6, pp. 1003-1006.
Pojar, Thomas R., and David C. Bowden, 2004. Neonatal mule deer fawn survival in
West-Central Colorado. Journal of Wildlife Management: Vol. 68, No. 3, pp. 550-560.
Raganella-Pelliccioni, E, L. Boitani and S. Toso, 2006. Ecological correlates of roe deer
fawn survival in a sub-Mediterranean population. Canadian Journal of Zoology: Vol 84,
pp. 1505-1512.
Schede, Georg, Hubert Hendrichs, Christen Wemmer, 1994. Mother-young relations in
White-tailed deer. Journal of Mammalogy: Vol. 75, No. 2, pp. 438-445.
Shivley, Kirk J., A. William Alldredge, and Gregory E. Phillips, 2005. Elk reproductive
response to removal of calving season disturbance by humans. Journal of Wildlife
Management: Vol. 69, No.3, pp. 1073-1080.
Unsworth, James W., David F. Pac, Gary C. White and Richard M. Bartmann, 1999.
Mule deer survival in Colorado, Idaho, and Montana. Journal of Wildlife Management:
Vol. 63, No. 1, pp. 315-326.
Williams, Elizabeth S., Michael W. Miller, Terry J. Kreeger, and E. Tom Thorne, 2002.
Chronic wasting disease of deer and elk: review with recommendations for management.
Journal of Wildlife Management: Vol. 66, No. 3, pp. 551-563.
Wood, R.E. 1962. A productivity study of mule deer on the Middle Fork on the Salmon
River, Idaho. Idaho Fish and Game Department Federal Aid Project, W133R1. p.35
Yoakum, J. 1966. Life and death of deer herds. In: University of California Agriculture
Extention Service Deer Seminars, University of California, Eureka. pp. 11-19.