There is considerable evidence that amphibians are declining globally due to various anthropogenic stressors. Cattle grazing in wetlands is a stressor that may have negative impacts on amphibians and has not been investigated intensively. Cattle could have a negative effect on larval amphibians by decreasing water quality through deposition of nitrogenous waste. Reduction in water quality also may compromise immune function by inducing stress thus making larvae more susceptible to pathogens. My objective was to quantify differences in amphibian larvae community metrics, water quality, and pathogen prevalence between cattle-access and non-access wetlands. I also measured fish abundance and biomass of filamentous algae and detritus, because these variables are known to influence larval amphibian populations, and may be affected by cattle. My study was conducted at the University of Tennessee Plateau Research and Education Center on the Cumberland Plateau, Tennessee. I sampled amphibian larvae and fish 2X per week, water quality 2X per month, and algal and detrital biomass 1X per month at each wetland from March – August 2005 and 2006. I also opportunistically collected American bullfrog (Rana catesbeiana) and green frog (R. clamitans) tadpoles from cattle-access and non-access wetlands during three seasons (winter, summer, and autumn), tested them for pathogens, and noted histopathological changes. In general, relative abundance, species richness, and species diversity of amphibian larvae were greater in non-access wetlands. Mean relative abundance of green frog and American bullfrog (and all other ranid tadpoles) was greater in non-access wetlands. Dissolved oxygen was lower, while specific conductivity and turbidity were higher in cattle-access wetlands. Detrital and algal biomass was lower and greater in cattle-access wetlands in compared to non-access wetlands, respectively. Some changes were noted in aquatic invertebrate and fish abundance between land uses. Tadpoles also were infected by a variety of known amphibian pathogens (e.g., Frog virus 3, Aeromonas hydrophila), but land-use trends often were dependent on species and season. My results suggest cattle negatively impact water quality, detritus, and relative abundance of some larval amphibian species. Fencing cattle from wetlands may be a prudent amphibian conservation strategy.

Objectives were to 1) examine effects of heat stress on maturing oocytes to alter the ability of resulting embryos to develop after fertilization, 2) evaluate blastocyst development of compact morulae derived from control or heatstressed oocytes after culture at 38.5°C or 41.0°C, and 3) evaluate effects of heat stress on compact morulae to alter sex ratio. Culture of cumulus oocytes at 41.0°C did not alter ability of presumptive zygotes (PZ) to cleave; however, the proportion of embryos that cleaved to the 8- to 16-cell stage was lower (P = 0.01). Also, the proportion of 8- to 16-cell embryos derived from heat-stressed oocytes undergoing compaction was lower (P = 0.01). Effects of heat stress to reduce compaction was without consequence on morphology, as quality scores of embryos derived from heat-stressed oocytes were similar to those derived from nonheat-stressed oocytes. Application of heat stress to compact morulae derived from nonheat-stressed oocytes did not affect blastocyst development. Also, blastocyst development of compact morulae derived from heat-stressed oocytes was similar to those derived from nonheat-stressed controls. However, if compact morulae derived from heat-stressed oocytes were exposed to 41.0°C, blastocyst development was reduced (P = 0.007). This effect was coincident with an increase in the proportion of degenerate embryos (P = 0.02). Temperature at which oocytes were matured did not alter sex ratio of resulting blastocysts. Rather, there was a tendency for embryo temperature to increase the proportion of male embryos that survived (P < 0.06). Results described herein are significant as they not only clarify the extent to which heat stress during maturation reduces embryonic development after fertilization but are also informative of heat-induced perturbations that carry over to increase the susceptibility of resulting embryos to heat stress. With this in mind, results raise possible concerns about current practices of utilizing MOET in heat-stressed cattle with the intent of obtaining “developmentally-competent” embryos. Additionally, since it was also demonstrated that developmental competence of oocytes has an impact on the responsiveness of resulting embryos to heat stress, effort to clarify developmental competence of oocytes before utilizing in vitro derived embryos to improve fertility of heat-stressed dairy cows is needed.

Validation of a Three Dimensional Motion Capture System for Use in Identifying Characteristics of the Running Walk A three-dimensional (3-D) motion capture system was adapted for use in characterizing the biomechanics of the Running Walk, a stepping gait of the Tennessee Walking Horse (TWH) breed. Registered TWH (n = 4) were ridden through an arrangement of high-speed digital cameras at the walk (W) and running walk (RW). Infrared reflective markers (65 per horse) were used to track body segments and joint centers. Five trials per gait per horse were recorded. A dynamic 3-D model was created and used to label and track body segments. Temporal stride characteristics and joint angle values were extracted by a custom script file and gait formulas were calculated for each gait per horse. Temporal stride characteristics and gait formulas of both W and RW were found to be similar to those previously reported. Overstride (OS), which has not previously been described, increased from W to RW (P < 0.0001). The increase in OS accounted for 96% of the increase in stride length; only 4% of the increase in stride length is due to an increase in step length. OS was positively correlated to velocity and stride length (P < 0.0001), and negatively correlated to front stance duration, hind stance duration and total stance duration (P < 0.0001). A long OS would appear to be related to the flexibility of the proximal hind limb, the pelvis and possibly the lumbar spine. Hind stance duration as a percent of total stride time, advance placement as a percent of total stride time, and advance liftoff as a percent of total stride time did not differ between W and RW (P > 0.05), suggesting that the RW is not simply a faster version of W. 3-D analysis allowed for thorough analysis of joint angles. The joint angles of the carpus were highly correlated to stride length, OS, and advance placement (P < 0.0001), but were not correlated to velocity (P > 0.05). These joint angles and gait events can be viewed as velocity-independent stride characteristics and may be suitable for making comparisons between horses traveling at different velocities. Identification of joint-specific velocity-independent stride characteristics may enhance our ability to associate lameness with an individual joint. KEYWORDS horse gait biomechanics

Conversion of tall fescue (Festuca arundinacea) to managed native warm-season grasses (nwsg) and associated forbs benefits many wildlife species that depend on early successional habitat. Planting nwsg, however, may not be necessary depending on the composition of the seedbank. Treatments were implemented in a randomized complete block design with replication during 2003 and 2004 at three study sites across Tennessee to determine the effects of seasonal herbicide applications and disking on tall fescue eradication and resulting vegetation composition and structure. Treatments included: fall glyphosate (2.2 kg ai/ha; Gly-4 2qt/ac); fall glyphosate followed by winter disking; fall imazapic (0.2 kg ai/ha; Plateau 12 oz/ac); fall imazapic followed by winter disking; spring glyphosate; spring glyphosate followed by fall disking; spring imazapic; and spring imazapic followed by fall disking. Vegetation composition and structure were measured June – September, and November 2004 and February, April, and June – September 2005. All treatments reduced tall fescue cover compared to control one growing season after treatment. Fall herbicide applications with and without disking decreased tall fescue cover more than spring treatments when measured two growing seasons after treatment. Reduction in tall fescue improved openness at ground level during the brooding season and angle of obstruction during the wintering period for bobwhites. Disking following herbicide application increased cover of bobwhite food plants, including common ragweed (Ambrosia artemisifolia), beggar’s-lice (Desmodium spp.), and beggar-ticks (Bidens spp.). Imazapic increased cover of desirable nwsg, such as broomsedge bluestem (Andropogon virginicus); however on 2 sites, imazapic applications resulted in increased cover of orchardgrass (Dactylis glomerata), which was structurally identical to tall fescue. Fall glyphosate applications are recommended to eradicate tall fescue. If certain undesirable plants are suspected to germinate from the seedbank after tall fescue is removed, an imazapic application may be necessary in April or May to control species such as johnsongrass (Sorghum halapense), crabgrass (Digitaria sanguinalis), and yellow nutsedge (Cyperus esculentus).

Prior research in our lab has demonstrated a significant association between the incidence of subclinical mastitis and neutrophil functions with polymorphisms of the CXCR1 gene in Holstein dairy cattle. The objective of this study was to evaluate the specificity of the response relative to CXCR1 and potential involvement of intracellular signaling pathways. Migration was evaluated in cows of both homozygous genotypes (n=7 each) in response to high and low doses of interleukin-8 (IL -8; specific for CXCR1 and CXCR2), epithelial neutrophil activating peptide (ENA-78; specific for CXCR2) or zymosan activated sera (ZAS; complement receptors). Cows with a GG genotype had significantly more migration in response to both 12.5 and 50 nM doses of IL -8 (p<0.05) compared to cows with a CC genotype. Although a similar trend was observed for 50 nMENA-78 (p<0.07), this was not evident with the 12.5 nM dose. This result was comparable to ZAS, where the 5%dose caused significantly more neutrophil migration in cows with a GG genotype than those with a CC genotype (p<0.03), while the response to the 1% dose of ZAS was similar between genotypes. p38 MAPK and PKB phosphorylation were evaluated prior to and following stimulation with the high doses of each ligand. Relative increases in p38 MAPK phosphorylation were greater in neutrophils from cows with a GG genotype when compared to those with a CC genotype regardless of treatment with rhu-IL-8, rhu-ENA-78, and ZAS or not (p<0.001), But CC cows had higher baseline levels of p38-MAPK phosphorylation than GG cows. Therefore, the lower increase in phosphorylation in neutrophils from CC cows may have been due to higher starting levels. Increases in PKB phosphorylation also were greater in neutrophils from cows with a GG genotype when compared to a CC genotype when treated with ZAS, but not other ligands. Because no differences between genotypes were observed at time zero this may be tied to the altered p38 MAPK pathway. Future research will be aimed at further elucidating the signaling pathways causing functional differences in neutrophils from cows with different CXCR1 genotypes.

Since 1912 concentrations of the major anions and cations (except calcium) in Bear Lake water have shown a steady decrease which has been attributed to a dilution of Bear Lake by Bear River water, Bear Lake having been used as a reservoir for Bear River water since 1918. This study examined the changes which have occurred in Bear Lake water chemistry since 1912 and tested the validity of the dilution theory. Simple water and salinity budgets were determined for the Bear Lake system and used to simulate the effect of Bear River storage patterns since 1918 on the concentrations of sodium, potassium, magnesium, chloride, and sulfate in Bear Lake. Comparison of predicted concentrations with observed concentrations indicates that the dilution theory is a valid one. Field studies were conducted during the spring, summer, and fall of 1971 to describe the distribution of the major ions in Bear Lake with respect to space and time. No significant differences were found between samples collected.

The acceptable conditions for good fish production in large mountain streams are not well-known. A fishery can be properly managed only if the manager has sufficient knowledge of the carrying capacity of the habitat, the survival and mortality of the population, and the movements of the fish within the population. My study is an attempt to answer some of these questions about the self-sustaining populations of brown trout (Salmo trutta fario Linnaeus) and mountain whitefish (Prosopium williamsoni Girard) in a 5-mile section of Logan River, Utah.

Study of MHC polymorphism

The thermophilic archaeon sulfolobus acidocaldarius

Protein phosphorylation during postembryonic development of rice moth corcyra cephalonica