Lisa I. Muller

EFFECTIVENESS OF ANTAGONISTS FOR TILETAMINE-ZOLAZEPAM/XYLAZINE IMMOBILIZATION IN FEMALE WHITE-TAILED DEER

A combination of tiletamine-zolazepam/xylazine (TZ/X) is effective in the chemical immobilization of white-tailed deer (Odocoileus virginianus); however, the lengthy duration of immobilization may limit its usefulness. From October to November 2002, 21 captive female deer were assigned randomly to an α2 antagonist treatment to reverse xylazine-induced sedation (seven does per group). All deer were given 220 mg of TZ (4.5±0.4 mg/kg) and 110 mg of X (2.2±0.2 mg/kg) intramuscularly (IM). Antagonist treatments were either 200 mg of tolazoline (4.0±0.4 mg/kg), 11 mg of atipamezole (0.23±0.02 mg/kg), or 15 mg of yohimbine (0.30±0.02 mg/kg) injected, half intravenously and half subcutaneously, 45 min after the IM TZ/X injection. In addition, 10 other deer (five per group) were immobilized as before and then given tolazoline (200 mg) after 45 min, with either a carrier (dimethyl sulfoxide [DMSO]) or carrier (DMSO) plus flumazenil (5 mg) to reverse the zolazepam portion of TZ. Mean times from antagonist injection until a deer raised its head were different for α2 antagonist treatments (P = 0.02). Times were longer for yohimbine (62.3±42.7 min) than for either atipamezole (24.3±17.1 min) or tolazoline (21.3±14.3 min). Mean times from antagonist injection until standing were not different (P=0.15) among yohimbine (112.0±56.4 min), atipamezole (89.7±62.8 min), or tolazoline (52.6±37.2 min). A sedation score based on behavioral criteria was assigned to each deer every 30 min for 5 hr. On the basis of sedation scores, tolazoline resulted in a faster and more complete reversal of immobilization. Flumazenil treatment did not affect recovery.

A COMPARISON OF CARFENTANIL/XYLAZINE AND TELAZOL®/XYLAZINE FOR IMMOBILIZATION OF WHITE-TAILED DEER

From October 2001 to January 2002, captive free-ranging white-tailed deer (Odocoileus virginianus) were immobilized with a combination of carfentanil citrate and xylazine hydrochloride. From this study, we selected a dose of carfentanil/xylazine for the purpose of comparing immobilization parameters and physiologic effects with those of a combination of tiletamine and zolazepam (Telazol®) and xylazine. Animals were initially given intramuscular injections of 10 mg xylazine and one of four doses of carfentanil (i.e., 0.5, 1.0, 1.5, and 2.0 mg). A carfentanil dose of 1.2 mg (x̄±SD=23.5±3.2 μg/kg) and 10 mg xylazine (0.2±0.03 mg/kg) were selected, based on induction times and previously published reports, to compare with a combination of 230 mg of Telazol® (4.5±0.6 mg/kg) and 120 mg xylazine (2.3±0.3 mg/kg). Time to first observable drug effects and to induction were significantly longer for deer treated with carfentanil/xylazine than with Telazol®/xylazine (P<0.01). Hyperthermia was common in deer immobilized with carfentanil/xylazine, but heart rate, respiration rate, and hemoglobin saturation were within acceptable levels. Degree of anesthesia of deer immobilized with Telazol®/xylazine was superior to deer immobilized with carfentanil/xylazine. The combination of 120 mg of naltrexone hydrochloride and 6.5 mg of yohimbine hydrochloride provided rapid and complete reversal (1.9±1.1 min) of carfentanil/xylazine immobilization. Animals immobilized with Telazol®/xylazine had long recovery times with occasional resedation after antagonism with 6.5 mg of yohimbine. The combination of carfentanil and xylazine at the doses tested did not provide reliable induction or immobilization of white-tailed deer even though drug reversal was rapid and safe using naltrexone and yohimbine.

Borrelia burgdorferi Not Detected in Widespread Ixodes scapularis (Acari: Ixodidae) Collected From White-Tailed Deer in Tennessee

ABSTRACT Lyme disease (LD), caused by the bacterium Borrelia burgdorferi and transmitted in the eastern United States by blacklegged ticks, Ixodes scapularis Say, is classified as nonendemic in Tennessee and surrounding states in the Southeast. Low incidence of LD in these states has been attributed, in part, to vector ticks being scarce or absent; however, tick survey data for many counties are incomplete or out of date. To improve our knowledge of the distribution, abundance, and Borrelia spp. prevalence of I. scapularis, we collected ticks from 1,018 hunter-harvested white-tailed deer (Odocoileus virginianus (Zimmerman)) from 71 of 95 Tennessee counties in fall 2007 and 2008. In total, 160 deer (15.7%) from 35 counties were infested with adult I. scapularis; 30 of these counties were new distributional records for this tick. The mean number of I. scapularis collected per infested deer was 5.4 ±0.6 SE. Of the 883 I. scapularis we removed from deer, none were positive for B. burgdorferi and one tested positive for B. miyamotoi. Deer are not reservoir hosts for B. burgdorferi; nevertheless, past surveys in northern LD-endemic states have readily detected B. burgdoreferi in ticks collected from deer. We conclude that I. scapularis is far more widespread in Tennessee than previously reported. The absence of detectable B. burgdorferi infection among these ticks suggests that the LD risk posed by I. scapularis in the surveyed areas of Tennessee is much lower than in LD-endemic areas of the Northeast and upper Midwest.

Excursive Behaviors by Female White-tailed Deer during Estrus at Two Mid-Atlantic Sites

Abstract Current research suggests that female white-tailed deer (Odocoileus virginianus) will adopt sedentary breeding strategies in populations with an abundance of males and a more active mate-searching strategy in low-density or unbalanced herds. We used GPS collars to document the movements of 10 female deer during the breeding season at two Mid-Atlantic study sites that support high-density herds with nearly equal sex ratios. We calculated 95% and 50% seasonal and weekly kernel home ranges and the daily percentage of points located outside of the seasonal home range (SHR). Peaks in weekly home range size and in the percentage of points located outside of the SHR occurred between 7 Nov. and 9 Dec. (x ¯  =  22 Nov.) for eight deer. Past data from one of the study sites have indicated that most breeding activity occurs from 5–25 Nov. Peaks in the percentage of points outside of the SHR corresponded to brief (x ¯  =  24.0 h, sd  =  18.2 h; range 8–68 h) excursions. On peak days, 46–100% (x ¯  =  68.3%, sd  =  17.1%) of data points were located outside of the SHR. No other excursions were observed during the 17 wk study period. Our results suggest that female deer may travel outside of their home range during the breeding season even when presented with an abundance of potential mates; these data suggest females are engaging in a discrete form of mate selection.

Field Use of Isoflurane for Safe Squirrel and Woodrat Anesthesia

Abstract We evaluated a chamber and nose cone method of isoflurane delivery for anesthetizing eastern gray squirrels (Sciurus carolinensis; summer n = 43, winter n = 48) and Allegheny woodrats (Neotoma magister; summer n = 24, winter n = 13) for use when pain or stress was possible from sampling procedures. Mean induction time for squirrels (from beginning of isoflurane administration to safe removal from trap), was 4.63 ± 0.58 minutes. Squirrels awoke more quickly in summer (1.40 ± 0.15 min) than in winter (3.62 ± 0.24 min) after removal of the nose cone. We manually restrained woodrats and administered the nose cone for 0.5 minutes to each animal. Woodrats awoke after 4.76 ± 0.58 minutes following the final dose of isoflurane for both seasons. These methods are useful for working with small mammals in the field and provide an appropriate anesthetic when there may be more than slight pain or distress.

Seasonal Forage Availability and Diet for Reintroduced Elk in the Cumberland Mountains, Tennessee

Abstract Cervus elaphus (Elk) were reintroduced into the Cumberland Mountains, Tennessee over a 3-year period beginning in December 2000. We radio-collared 159 Elk and monitored them by aerial telemetry from February 2001 to June 2003. Locations (n = 321) were used to develop a core herd home range (789-ha sampling area) to assess Elk seasonal forage use and availability. We monitored diet and resource availability from November 2003 to October 2004 by microhistological analysis of feces and vegetation sampling, respectively. We compared the relative availability of individual plant species (% cover) to the relative percentage of plant species found in fecal samples. A positive significant mean difference indicated plant species used in greater proportion to availability. Lolium arundinaceum (Tall Fescue) comprised 35.1% of the winter diet, and graminoids (65.9%) were the dominant forage class overall. The most selected graminoid was Andropogon gerardii (Big Bluestem). The diet shifted in the spring to a mixture of woody plants (28.1%), forbs (19.4%), and graminoids (38.4%). Carex spp. (sedges) and Juncus spp. (rushes) were the most selected graminoids. The highest seasonal use of forbs (45%) and legumes (23%) occurred during summer, with Impatiens spp. (jewelweed; 27%) as the dominant and most selected plant in the diet. The dominant fall forage class was woody plants (37.4%). Quercus spp. (oaks; vegetation and acorns 14.3%) were the most used woody plants with oak acorns comprising 9.7% of the Elk diet. We suggest that historic evidence, presence of native grasses, and Elk diets indicate that oak savannas could be an ideal habitat type for Elk in the reintroduction zone of Tennessee.

Do Odocoileus virginianus Males Produce Y-Chromosome-Biased Ejaculates? Implications for Adaptive Sex Ratio Theories

Abstract The theory of adaptive sex ratio variation assumes that parents can increase their fitness by investing in the offspring sex that will gain the greatest lifetime reproductive success. Many adaptive sex ratio hypotheses imply or predict a female-mediated physiological mechanism that facilitates parental control. However, the ability of females to control offspring sex ratio could be significantly affected if males provided X- or Y-chromosome-biased ejaculates, as was recently discovered in domestic artiodactyls. To determine whether this occurs in white-tailed deer (Odocoileus virginianus), we examined semen sex ratio of captive deer using DNA fluorescence flow cytometry. We also used microsatellite markers to assign paternity of fawns sired in previous years to determine if temporal patterns existed in fawn sex relative to conception date. The ratio of X- and Y-sperm did not differ from an expected 1:1 among deer or between collection periods. Median conception dates of male and female fawns sired in previous years were similar, and there were no apparent temporal trends in offspring sex. We find no evidence that skewed ejaculates occur in white-tailed deer.

Population Viability Analysis to Identify Management Priorities for Reintroduced Elk in the Cumberland Mountains, Tennessee

ABSTRACT We used an individual-based population model to perform a viability analysis to simulate population growth (&lgr;) of 167 elk (Cervus elaphus manitobensis; 71 male and 96 female) released in the Cumberland Mountains, Tennessee, to estimate sustainability (i.e., &lgr; > 1.0) and identify the most appropriate options for managing elk restoration. We transported elk from Elk Island National Park, Alberta, Canada, and from Land Between the Lakes, Kentucky, and reintroduced them beginning in December 2000 and ending in February 2003. We estimated annual survival rates for 156 radio-collared elk from December 2000 until November 2004. We used data from a nearby elk herd in Great Smoky Mountains National Park to simulate pessimistic and optimistic recruitment and performed population viability analyses to evaluate sustainability over a 25-year period. Annual survival averaged 0.799 (Total SE = 0.023). The primary identifiable sources of mortality were poaching, disease from meningeal worm (Parelaphostrongylus tenuis), and accidents (environmental causes and unintentional harvest). Population growth given pessimistic recruitment rates averaged 0.895 over 25 years (0.955 in year 1 to 0.880 in year 25); population growth was not sustainable in 100% of the runs. With the most optimistic estimates of recruitment, mean &lgr; increased to 0.967 (1.038 in year 1 to 0.956 in year 25) with 99.6% of the runs failing to be sustainable. We suggest that further translocation efforts to increase herd size will be ineffective unless survival rates are increased in the Cumberland Mountains.

Retrospective study of central nervous system lesions and association with Parelaphostrongylus species by histology and specific nested polymerase chain reaction in domestic camelids and wild ungulates.

Formalin-fixed, paraffin-embedded tissues from elk (Cervus elaphus), goats, and camelids with case histories and lesions suggestive of Parelaphostrongylus tenuis were examined by histology to characterize lesions that could aid in definitively diagnosing P. tenuis infection. Additionally, sections of paraffin-embedded tissue were used in a nested polymerase chain reaction (nPCR) using Parelaphostrongylus-specific primers to determine how PCR results corresponded with histological findings. Histological changes in brain and spinal cord consisted of linear tracks of hemorrhage; tracks or perivascular accumulations of hemosiderin-laden macrophages; acute foci of axonal degeneration and/or linear glial scars; and perivascular, parenchymal, or meningeal accumulations of eosinophils and/or lymphocytes and plasma cells. Of the 43 samples with histologic lesions consistent with neural larval migrans, 19 were PCR positive; however, only 8 were confirmed Parelaphostrongylus by DNA sequencing. Additionally, 1 goat was identified with a protostrongylid that had a 97% identity to both Parelaphostrongylus odocoilei and a protostrongylid nematode from pampas deer (Ozotoceros bezoarticus celer) from Argentina. None of the histologic lesions individually or in combination correlated statistically to positive molecular tests for the nematode. The results indicate that it is possible to extract Parelaphostrongylus DNA from formalin-fixed, paraffin-embedded tissue, but extended fixation presumably can cause DNA crosslinking. Nested PCR provides another diagnostic tool to identify the cause of neurologic disease in camelids and elk with histologic lesions consistent with neural larval migrans. Furthermore, potential novel protostrongylid DNA was detected from a goat with lesions consistent with P. tenuis infection, suggesting that other neurotropic Parelaphostrongylus species may occur locally.

RABIES SURVEILLANCE AMONG BATS IN TENNESSEE, USA, 1996-2010

Abstract Rabies virus (RABV) infects multiple bat species in the Americas, and enzootic foci perpetuate in bats principally via intraspecific transmission. In recent years, bats have been implicated in over 90% of human rabies cases in the US. In Tennessee, two human cases of rabies have occurred since 1960: one case in 1994 associated with a tricolored bat (Perimyotis subflavus) RABV variant and another in 2002 associated with the tricolored/silver-haired bat (P. subflavus/Lasionycteris noctivagans) RABV variant. From 1996 to 2010, 2,039 bats were submitted for rabies testing in Tennessee. Among 1,943 bats in satisfactory condition for testing and with a reported diagnostic result, 96% (1,870 of 1,943) were identified to species and 10% (196 of 1,943) were rabid. Big brown (Eptesicus fuscus), tricolored, and eastern red (Lasiurus borealis) bats comprised 77% of testable bat submissions and 84% of rabid bats. For species with five or more submissions during 1996–2010, the highest proportion of rabid bats occurred in hoary (Lasiurus cinereus; 46%), unspecified Myotis spp. (22%), and eastern red (17%) bats. The best model to predict rabid bats included month of submission, exposure history of submission, species, and sex of bat.