A 19.3-km section of U.S. Highway 64 in Washington County, North Carolina was rerouted to a 4-lane, divided highway with 3 wildlife underpasses during 2001–2005. I determined the short-term population and genetic impacts of the new highway on American black bears (Ursus americanus). I used DNA from hair samples collected during 7 weekly sampling periods within the project area of the new highway and a nearby control area during 2000 (pre-construction phase) and 2006 (post-construction phase; n = 70 sites for each study area). DNA from the hair samples was used to obtain genotypes of sampled bears using 10 microsatellite markers. I created capture histories of all identified individuals and used closed mark-recapture models in Program MARK to estimate abundance. Population abundance decreased on the treatment area from 68 (CI = 53–82) before construction to 20 (CI = 14–26) after completion of the highway. On the control area, population abundance decreased from 144 to 101. Using permutation procedures, I determined that the decrease in population abundance on the treatment area was greater compared with the control area (P = 0.0012). Additionally, I used bear visits to the sampling sites with multi-season occupancy models in Program MARK to determine if site occupancy decreased following the construction of the highway and if any decrease was a function of distance from the highway. Following highway construction, site occupancy decreased more on the treatment area than the control area but was not a function of distance from the highway. Finally, I used the microsatellite data to compare gene flow, isolation by distance, heterozygosity, allelic diversity, population assignment, and genetic structure (Fst) before and after completion of the highway. I did not observe any treatment effects for these genetic measures. I speculate that displacement during the construction of the highway and mortality due to bear-vehicle collisions contributed to the population decline and decrease in site occupancy. Although the wildlife underpasses facilitated genetic and demographic connectivity, my study indicates that the potential impact of new highways on black bear population abundance is an important consideration for transportation infrastructure planning.

An 84 d randomized block design using 96 beef calves (238.8 + 20.1 kg) in each of two years was used to assess the efficacy of energy supplementation and glucomannan (MTB) to alleviate tall fescue toxicosis. Groups of four calves were randomly assigned to 24 endophyte-infected tall fescue pastures (1.23 + 0.06 ha). Pastures of calves were randomly assigned to treatments: unsupplemented (CON), supplemented with soybean hulls (SH) at 0.33% BW (DM basis; LO), supplemented with SH at 0.66% BW (DM basis; HI), LO plus 20 g·hd-1·d-1 MTB-100® (LO-MTB), HI plus 20 g·hd-1·d-1 MTB-100® (HI-MTB). Calves were weighed and serum collected every 21 days. Fecal grab samples were taken from d 55 to d 59 and analyzed for dry matter chromium and ergot alkaloid concentrations. Tympanic temperatures were taken from one calf for 3 days each week from d 59 to d 84. Data were analyzed using the MIXED procedure in SAS with contrasts of effects of MTB, level of SH supplementation (LEVEL), MTB x LEVEL interaction, and CON vs. supplemented (SUPP). Treatments differed in ADG (P < 0.01) with LEVEL affecting weight gains (P < 0.01). Supplemented calves had increased weight gains compared to CON (P < 0.01). Supplementation increased gain per hectare (P < 0.01) and was influenced by LEVEL (P < 0.01). Control calves excreted higher concentrations of ergot alkaloids than SUPP (P < 0.01). Forage and total DMI increased as a result of supplementation (P < 0.01). Prolactin levels differed among the treatments on d 63 and 84 (P < 0.01) with increases attributed to LEVEL (P < 0.05). There were differences between CON and SUPP (P < 0.01) on d 63 and 84, where SUPP increased prolactin concentrations to twice that of CON. Tympanic temperatures were similar among treatments (P > 0.05); daily maximum temperatures and diurnal range differed among the treatments (P < 0.01). SUPP animals had lower maximum temperatures and decreased diurnal range compared to CON (P < 0.01). These findings indicate that SH supplementation can lessen the severity of fescue toxicosis; however, glucomannan fed at the current level only affected tympanic temperature.

Global decline of amphibian populations has been linked to various anthropogenic stressors. Recent studies have quantified the influences of cropland agriculture and deforestation; however, few have examined the impacts of allowing cattle access in wetlands on resident amphibians. I compared four wetlands exposed to cattle grazing for >10 years against four wetlands that had not been grazed for >10 years, at the University of Tennessee Plateau Research and Education Center. At each wetland I measured species richness, diversity, and species-specific relative abundance of postmetamorphic amphibians captured in pitfall traps and during breeding call surveys, amphibian egg mass abundance, shoreline vegetation structure, and soil compaction from March – August 2005 and 2006. Pathogen prevalence and histopathological changes were measured from a subsample of opportunistically collected amphibians. Landscape characteristics were quantified and related to amphibian community structure. Relative abundance of green frog metamorphs was 9.8X greater in 2006 and 2.3X greater in 2005 at non-access wetlands. Relative abundance of American toads was 68X and 76X greater at cattle-access wetlands in 2005 and 2006, respectively. Breeding call abundance of American toad, Fowler’s toad, and Cope’s gray treefrog was 4 – 25X greater at cattleaccess wetlands in 2006. There were 2X more spring peepers and pickerel frogs calling at non-access wetlands in 2005 and 2006, respectively. Species richness, diversity, and egg mass abundance were not significantly different between land-use types each year. In general, body size followed a density-dependent relationship across species. Height and percent horizontal and vertical cover of shoreline vegetation were 74%, 25% and 84% greater, respectively, in non-access wetlands in 2005; trends were similar in 2006. Soil compaction was 55% greater at cattle-access wetlands. Pathogen prevalence and histopathological changes did not differ between land uses. Landscape analyses revealed species-specific associations related to wetland isolation and geometric complexity of the landscape between wetlands. My results suggest that cattle influence community composition and postmetamorphic body size of amphibians, but effects are speciesspecific. Differences in postmetamorphic abundance may be related to less vegetation structure and lower water quality at cattle-access wetlands. Fencing cattle from wetlands may be a prudent conservation strategy for some amphibian species.

Previous studies on macrolide resistance in Campylobacter were primarily focused on the isolates from various origins using in vitro systems. In this study, both in vitro and in vivo experiments were conducted to examine the development, stability, and genetic basis of macrolide resistance in C. jejuni. All in vitro and in vivo selected EryR mutants were derived from the same parent strain C. jejuni NCTC 11168. To determine if long-term exposure of low-level EryR C. jejuni to low-dose tylosin selects for high-level EryR mutants (MIC > 512 μg/ml), two low-level EryR mutants (MIC = 32 or 64 μg/ml) were used to inoculate chickens at 15 days of age in two independent experiments. Total and EryR C. jejuni populations in swabs collected at different time points were determined by differential plating and MIC test. The in vitro stability was tested by repeated subculturing of EryR mutants in Ery-free broth medium. The in vivo stability was tested by inoculating 3-day-old chickens (12-13 birds/group) receiving nonmedicated feed with EryR mutants and collecting cloacal swabs from each chickens at 12, 22, 38, and 47 days of age. Total and EryR C. jejuni populations in culture (after 10, 20 and 33 passages) or swab were determined by differential plating and MIC test. Genomic DNA from each of 63 selected EryR mutants was used for PCR amplification and sequence analysis of 23S rRNA gene and ribosomal proteins L4 and L22. Mutation in CmeABC multidrug efflux pump was transferred to EryR strains to determine the role of CmeABC efflux pump in Ery resistance. Chicken studies showed that the length of exposure time to subtherapeutic level of tylosin is not a sole factor contributing to the emergence of highly EryR Campylobacter. Prolonged exposure of low-level EryR C. jejuni (MIC = 32 or 64 μg/ml) to tylosin did not select for highly EryR mutants. The low- level Ery resistance (MIC = 32μg/ml) was stable after 10 passages in vitro but majority of C. jejuni were sensitive to Ery after 20 passages. The instability of low-level Ery resistance was also observed in chickens as early as 9 days postinoculation and EryR mutants were rarely isolated 35 days postinoculation. However, high-level Ery resistance (MIC > 512μg/ml) displayed remarkably stability in vitro and in vivo. All high-level EryR mutants selected in vivo displayed the A2074G mutation in 23S rRNA gene, distinct from the specific mutation (A2074C) observed in all highly EryR mutants selected in vitro. No mutations were observed in ribosomal proteins L4 for all in vitro selected EryR mutants but specific mutations in L4 (G74D or G57D) were widely found in low level EryR mutants selected in vivo (Ery MIC = 8-64 μg/ml). Insertion of three amino acids TSH at position 98 in L22 was only observed in mutants selected in vitro with Ery MIC ranging from 32-512 μg/ml. The CmeABC efflux pump worked synergistically with other mechanisms to confer Ery resistance in C. jejuni. Together, these findings indicated that C. jejuni utilize complex and different mechanisms to develop Ery resistance in vitro and in vivo.

Two 84-day grazing trials were conducted (Aug 24 – Nov 17, 2006; Jun 14 - Sept 7, 2007) near Spring Hill, TN to determine the efficacy of Endo-Fighter (R), an ADM Alliance Nutrition, Inc. product designed to be fed to cattle grazing or fed endophyte-infected fescue or hay and Prototype, an improved version of Endo-Fighter (R). Tall fescue pastures with >90% of pasture exhibiting infestation (E+), thus producing high concentration of ergot alkaloids in the grass, were grazed. In 2006 sixty weaned crossbred heifers (325 ± 17 kg) (2007, steers, 267 ± 18 kg) were used in a randomized block design (2007, CRD), blocked by previous treatment and randomly allotted to pastures with four animals per 1.2-ha paddocks and five replications per treatment. Treatments were ADM Alliance Nutrition, Inc. mineral products: 1) Mastergain (R) mineral = Control; 2) Endo-Fighter (R) mineral; 3) Prototype mineral. Animals had free choice access to E+ grass, water and shade. Heifers were weighed on d 0, 1, 28, 56, 83, and 84 (2006) and on d 0, 1, 22, 43, 64, and 85 (2007). In 2006 data collected were initial, d 28, d 56, and final weights, and ADG. In 2007 data collected were initial, d 22, d 43, d 64, and final weights, and ADG for each period. Blood serum was collected at each weigh date for prolactin analysis. Mineral consumption and animal grazing behavior were determined at 14-d intervals. Data were analyzed using the MIXED procedure of SAS. For all variables, contrasts were performed to compare Control to mineral supplements containing Endo-Fighter (R) or Prototype. In 2006 total ADG (kg) and average daily mineral consumption (g) were: 0.61, 170*; 0.56, 122*; 0.50, 146; for Control, Endo-Fighter (R) and Prototype, respectively (*P < .09). In 2007 data were 0.61, 134; 0.57, 147; 0.56, 116; for Control, Endo-Fighter (R), and Prototype, respectively. For both years, serum prolactin was not different (P > 0.05) among treatments. Animal performance and prolactin levels were not significantly affected by the feeding of Endo-Fighter (R) or Prototype in these trials. However, lack of response to Endo-Fighter (R) and Prototype in 2006 may have been attributed to mild weather conditions. In 2007 lack of response may have been a result of extreme heat and drought conditions.

Introduction: The Tennessee Valley Authority is vitally interested in the effect of phosphorous on crop yields and the nutritional value of these crops on livestock. They manufacture different phosphatic fertilizers and test them on farms and in laboratories. Financial assistance is given by the Tennessee Valley Authority to the Tennessee Experiment Station in this study of the feeding value of clover hays of varying phosphorous contents for growing beef calves. This experiment was originated to (1) study growth of calves fed rations differing only in the phosphorous content of the red clover hay; and (2) to study the availability to growing beef calves of the phosphorous in the red clover hays having a different phosphorous content.

The synthetic met-enkephalin syndyphalin-33 (SD-33) increases feed intak in sheep and recently-weaned pigs. An experiment focused on changes in hypothalamic levels of mRNA transcripts from the following genes: μ-opioid receptor (MOR), neuropeptide Y (NPY), orexin (hypocretin; HCRT), melanocortin 4 receptor (MC4R), and agouti-related protein (AGRP). There was no effect of treatment on BW or FI at any point in the study. There is a strong positive correlation (p <0.001) between MOR and MC4 that remains regardless of treatment or time. Weaning resulted in a numerical increase in hypothalamic MOR mRNA expression. There was a treatment effect of MOR expression levels 4 days postweaning. Hypothalamic NPY expression was unchanged through time or treatment. In VEH pigs, weaning resulted in increased hypothalamic expression of the HCRT gene at d 1 and d 7 postweaning (P(time) < 0.01). In SD pigs, an increase in HCRTexpression (relative to d 0) was observed at d 4 postweaning. Expression of HCRT did not significantly differ between treatment groups at d 1 and d 4, but HCRT expression was greater in VEH pigs than in SD pigs at d 7 (P(time x treatment) < 0.05). Expression of hypothalamic MC4R did not change through time, but a trend (P(treatment) = 0.07) was observed such that expression was less in SD pigs than in VEH pigs on d 1 and d 4 postweaning, possibly due to a numerical increase in expression in VEH pigs on d 1 relative to d 0. Expression of AGRP was decreased 1 d postweaning in VEH pigs but not in SD pigs,. On d 4, levels of AGRP expression were lower in SD pigs than in VEH pigs, and lower than d 0 levels as well. On d7, AGRP expression was less in VEH pigs than in SD pigs (P(time x treatment) < 0.01). Syndyphalin-33 has the potential to alleviate the negative effects of stress during weaning, and has the potential to increase feed intake through the melanocortinergic pathway. Further investigation is needed to more fully elucidate the complex mechanisms by which syndyphalin-33 may act to abrogate the post-weaning growth lag in pigs.

Anecdotal observations have suggested that muskrat (Ondatra zibethicus) populations were dramatically reduced in streams where the North American river otters (Lontra canadensis) were reintroduced. Muskrats predate upon freshwater mussels and it was speculated that river otter reintroduction could result in increased mussel numbers. My objectives were to evaluate the ecological relationship between otter, muskrat, and mussels on the Green and Nolin rivers in Mammoth Cave National Park (MCNP). Seventeen river otters were captured in or relocated to MCNP from January to May 2007. The augmentation was only marginally successful with 3 male river otters establishing home ranges within the park; of the remaining 13 animals, 10 individuals dispersed >35 km outside of the study area and 3 died shortly after release. Despite the relatively low success of the augmentation, scent-station surveys, trap-site visitation, and scat collection indicated that otter numbers had significantly increased on the Green River since Asmus‟ (2004) study, probably as a result of natural immigration and range expansion. Although spotlight surveys indicated that there was a concomitant decline in the muskrat population along the Green River from 2002 to 2008 (F1, 73 = 36.56, P < 0.0001), muskrat hair was only found in 1 of 48 (2%) river otter scats examined. That evidence, coupled with a relatively high number of both otters and muskrats on the Nolin River, did not indicate that the relationship between muskrats and otters in MCNP was causal. On a more extensive scale, I collected data on muskrat and otter presence at 95 randomly selected bridge crossings across Kentucky but centered on MCNP. I used a 2-species co-occurrence model in Program PRESENCE to determine if the presence of river otters was related to the presence of muskrats. This occupancy model indicated that muskrats occurred independently of river otters (φ = 1.02). Observer, water level, and substrate were important determinants of otter detection, whereas straight-line distance from original river otter release sites was an important occupancy covariate for river otters. Therefore, both my intensive and extensive data analyses do not support the notion of a negative interaction occurs between river otters and muskrats.

This thesis discusses the background information regarding the physiological effects the pig encounters during weaning as well as a potential factor that can be used to assist the pig during this time. Specifically, the research focus is to assess the ability of the tri-peptide opioid agonist, Syndyphalin-33 (SD-33), to increase feed intake and body weight and modulate immune responses during the post-weaning period. The results of this research have demonstrated that SD-33 increases feed intake, transiently increases growth hormone and cortisol levels, and increases total white blood cell counts while selectively increasing monocyte numbers in healthy weaned pigs. This research also demonstrates that, although co-treatment with SD-33 during an immune challenge of Salmonella enterica did not result in increased feed intake, SD-33 exerted effects relating to increasing the circulating populations of immune cells at 48 h postinjections, selectively increasing monocyte numbers. Based on these results, SD-33 may have the potential to be used as an agent to decrease the negative effects of stress during weaning in pigs. However, further investigation is needed to better understand the timing of effect, and to rule out any immunosuppressive effects, which would be detrimental to the animal’s well-being.

Specific objectives of this study were to examine growth response of the dominant follicle (DF) after administration of Folltropin-V (FSH and LH) at onset of luteolysis and investigate use of human chorionic gonadotropin (hCG) for decreasing ovulation time in lactating Holstein cows. On day 8 or 9 of a synchronized cycle, cows (n = 35) received an EAZI-BREED CIDR plus 100 μg of GnRH. CIDRs were removed 7 days later and cows were administered 500 μg cloprostenol. Concurrently, cows were randomly allocated to receive either 80 mg Folltropin-V (FSH, n = 19) or 4 mL of sterile saline (SAL, n = 16). Forty-nine hours later, cows that had received Folltropin-V or Saline were randomly subdivided to receive either 100 μg dose of GnRH or 3000 IU of hCG. Ultrasonography was performed to assess growth of the ovulatory follicle and confirm ovulation. Data were analyzed using the MIXED procedure of SAS. Size of the ovulatory follicle at time of GnRH/hCG administration was not different between Folltropin-V or Saline groups (17.1 ± 0.7 vs. 17.7 ± 0.6 mm, respectively; P = 0.521). Total growth of the ovulatory follicle from CIDR removal to GnRH/hCG administration did not differ between FSH (3.2 ± 0.6 mm) and Saline-treated cows (3.3 ± 0.4 mm; P = 0.891). When assessed from time of CIDR removal, ovulation occurred at a similar time for Folltropin-V (76.9 ± 0.7 h) and Saline-treated cows (78.0 ± 0.5 h; P = 0.196). When calculated from time of LH or hCG peak to ovulation, FSH-hCG cows presented the shortest time to ovulation (19.9 ± 0.4 h; P = 0.066). Whereas, from GnRH/hCG administration to ovulation, FSH-GnRH presented the earliest ovulation (25.0 ± 1.2 h; P = 0.013). In conclusion, Folltropin-V did not increase size of the ovulatory follicle at the time of GnRH/hCG administration. However, earlier ovulation occurred when combined with hCG as measured from time of gonadotropin peak. Conversely, when ovulation time is calculated from GnRH/hCG administration, FSH-GnRH produced the earliest ovulation.