No description available.

The available data examining the influence of rotational grazing on rodent responses are limited. This study investigated how rotational livestock grazing practices influence small mammal rodent abundances and species diversity. We looked for evidence of variation in the occurrence and/or numbers of certain rodent species among three plant community types (grassland, shrubland, grass-shrub mix), managed with or without grazing. We used Sherman live traps over a total of eight trapping sessions. We totaled 486 trapnights for each of the six plant community and grazing management combinations. The three plant community types were identified by visual cover. Out of the eight different species we captured, only Peromyscus maniculatus (North American deermouse) and Reithrodontomys megalotis (western harvest mouse) had sufficient captures to be analyzed for differences in abundance. Using all eight species to calculate the Shannon’s diversity index for each plot, we found evidence that rodent species diversity is less in grassland habitats than in shrubland habitats or grassland/shrubland mixed habitats (p

Rare, alpine, endemic species are particularly at risk for extinction. Alpine environments are especially vulnerable to climate change and human impacts, such as ski resort development and snowmaking. Draba asterophora Payson is a rare, alpine species that occurs only in three disjunct mountain-top regions surrounding Lake Tahoe. It is currently threatened by human impacts, such as ski resorts, as well as indirect influences of climate change and therefore in need of better understanding for conservation purposes. Draba asterophora may be able to serve as a case study for other similarly vulnerable, rare, alpine, endemic species with conservation needs. We utilized demographic, ecological, phylogenetic, and cytogenetic data to better understand D. asterophora's life history, habitat requirements, and delineate species boundaries. Draba asterophora occurs in three population clusters surrounding Lake Tahoe, segregated into two varieties, variety asterophora in the north (N) and south (S) and variety macrocarpa C. L. Hitchcock in the southwest (Sw). Populations exist on ski resort property in the north and south (variety asterophora) regions and thus face more threats. Therefore, these regions were the focus of long-term monitoring over a four year period. We assessed various morphological traits, survivorship and density estimates in these two population clusters (north and south). We created projection matrices for each population cluster and calculated finite rates of increase (λ), as well as reproductive and survivorship rates. The population projection matrices estimated growth rates close to 1.00 for both clusters (S: λ=0.977; N: λ=1.014), although neither cluster had reached a stable population structure. Plants in the north tended to be more robust, having more rosettes, inflorescences, flowers and fruits than the plants in the south. However, the plants in the northern population cluster did not have significantly higher brood sizes and the southern plants actually had larger seed to ovule ratios than those in the north ((S: x = 0.387l; N: x = 0.346). These results may be in part influenced by habitat differences (e.g. greater water availability in the north), specific site microclimate/microhabitat differences, genetic drift, and/or possibility polyploidy vigor (the northern cluster is tetraploid). However, as an autopolyploid, the NE cluster may have some difficulties with pairing in meiosis which could also contribute to its reduced seed to ovule ratios. Although the populations were found to be fairly stable currently, D. asterophora var. asterophora is potentially quite vulnerable to disturbance. All of the monitored populations in both clusters existed in small populations with low local densities confined to narrow geographic boundaries, and exhibit low fecundity. Because the taxon relies on survivorship of adults for population stability rather than new recruits, it is crucial to maintain stable adult populations in conservation efforts. Draba asterophora is similar to other alpine species tend, exhibiting high adult survivorship with low fecundity. We also examined the habitat requirements of D. asterophora by characterizing the abiotic habitat (soil chemical and texture analysis and site features such as aspect, slope, elevation) and the vegetative communities in D. asterophora sites. Draba asterophora sites all have fairly similar abiotic and biotic habitats despite large geographical separation, although some specific sites have unique characteristics as well. Draba asterophora habitats consist of steep, granitic slopes in the subalpine conifer zone with little understory. Draba asterophora's community may be facilitated by the diversity-stability hypothesis, as D. asterophora abundance (cover and/or frequency) was positively correlated with species richness and diversity, but negatively correlated with total vegetative cover (relative cover). In addition, D. asterophora has greater seed production (both seed/ovule ratio and brood size) in areas with greater species diversity. Draba asterophora does not appear to have many specific soil composition requirements or specific interspecific interactions, but generally occurs in diverse communities, albeit somewhat sparsely populated, in relatively open north-facing alpine habitats on steep granitic slopes. Changes in vegetation, topology and/or snow cover, due to disturbances such as grading, erosion, or snowmaking, may be detrimental to D. asterophora by rendering its habitat unsuitable. Therefore, D. asterophora habitat should be protected from further human impacts. Draba; the largest and most diverse genus in Brassicaceae, the mustard family, has complex phylogenetics due to its high degree of reticulate evolution, polyplodization, rarity and endemism. The D. asterophora complex has not been included in previous phylogenetic analyses. Only he northern population has been examined cytologically (2n=40). Thus, its taxonomy is poorly understood. We utilized one nuclear molecular marker, ITS, as well as two new chloroplast markers, trnS-G and trnH-psbA, to help resolve complex phylogenetic relationships and delimitation species boundaries within the D. asterophora complex. In addition, we examined the cytogenetics of all three population clusters to determine any differences in ploidy levels exist. The D. asterophora complex appears to be composed of three separately evolving trajectories differentiated by separate geographic regions surrounding Lake Tahoe, CA/NV. This is supported by both phylogenetic analyses as well as cytology. The combined DNA concatenated analysis demonstrated that all three regions form separate branches within the D. asterophora clade. Cytologically, chromosome counts were distinct in all three regions, with the southern cluster being a diploid (2n=20), the northern cluster an autotetraploid (2n=40), and the cluster in the southwest ( variety macrocarpa) an autooctoploid (2n=80). Based on these findings, we recommend that the three population clusters be treated as distinct taxonomic entities for conservation purposes. This demonstrates the importance of considering phylogenetics and ploidy levels, even of autopolyploids, in determining taxonomy, especially for rare, endemic species with disjunct habitats. Overall, this research suggests that the three geographic regions of the D. asterophora complex are distinct demographically and on own their evolutionary trajectories. Conservation efforts need to be targeted towards separate management of each population cluster. Maintaining stable adult populations, diverse plant communities, and preventing further destruction of habitat are the key conservation suggestions for D. asterophora.

Prolonging function of the corpus luteum (CL) is a method of suppressing estrus that maintains secretion of endogenous progesterone to keep mares out of heat naturally. The use of oxytocin to prolong CL function is becoming more popular. In these therapies, upregulation of cyclooxygenase-2 is inhibited, which impairs prostaglandin F2α ( PGF2α) production. Intramuscular (IM) administration of 60 IU of oxytocin once daily from 7 to 14 days after ovulation is currently the most common treatment protocol. Although that protocol is efficacious in ≥70% of treated mares, the need for daily administration is a drawback to its use. A proprietary slow-release oxytocin formulation (SR-OT) with a two-injection protocol to prolong CL function was evaluated in the first experiment. Mares were examined to determine the day of ovulation (day 0) and then randomly assigned either to a non-treated control group or an SR-OT treatment group (n = 8 mares/group). Mares in the treated group received 1.0 mL of SR-OT containing 2,400 IU oxytocin IM once on Day 7 and again on Day 10 after ovulation. Jugular blood samples were collected on day 0 and then every M, W, and F continuously. Serum progesterone concentrations were evaluated to assess CL function, which was prolonged in 0/8 (0%) control mares and 6/8 (75%) of the SR-OT treated mares (p< 0.01). In a second study, the ability of the endometrium to synthesize PGF2α was evaluated in mares in a state of prolonged CL function. Mares were designated into groups 50-59, 60-69, or 70-79 days post-ovulation (50s, 60s, 70s) and 14-day post-ovulation controls. PGF2α synthesis was evaluated by measurement of a prostaglandin metabolite in response to a single 10 IU intravenous oxytocin bolus (0 minutes). Blood samples were collected serially from 30 minutes before until 120 minutes after oxytocin administration. The metabolite response was significantly higher in the 70s versus the 50s and 70s versus the 60s groups (p< 0.001; p< 0.02, respectively); and there was no significant difference between the 70s group and the control group (P>0.36). Luteal function was maintained after oxytocin administration in 4/4, 3/4, and 0/3 mares in the 50s, 60s, and 70s groups, respectively. Collectively, these results indicate that the luteolytic mechanism returns approximately 70 days into the period of prolonged CL function.

No description available.

No description available.

The purpose of this research was to investigate the effects of climatic variations upon the daily activities of grazing cattle. The activities of individual cows on a partially seeded salt desert shrub range were observed and recorded during three grazing periods. Two of the periods were during consecutive winters and the other during the spring. Climatic variations during the second winter period were quantified and compared to changes in the daily activity patterns of the cattle. Distinctly different daily routines of cattle activities were evident for the winter and spring seasons. In the spring, the cattle grazed, traveled, and drank more each day than they did during the winter months. The increase in these activities was attributed to the more temperate climatic conditions and the higher energy demands of lactation. Air temperature, changes in barometric pressure, windspeed, precipitation, snow depth, and radiation all influenced cattle activities in the winter. Decreasing air temperature and rapid fluctuations in barometric pressure both correlated significantly with increased grazing time. Increasing windspeed and greater snow depth caused the cattle to travel less distance daily. The cattle ceased grazing during snowstorms. They oriented themselves at right angles to the sun while standing and lying. The modifications which occurred in daily activity patterns were shown to be apparently directed toward the conservation of energy during periods of climatic stress.

Enterovirus D68 (EV-D68) is a virus that normally causes disease in children. While this virus typically causes a respiratory infection, in 2014, a large outbreak of the virus was associated with patients that had paralysis of the arms or legs. Even though the virus was discovered in 1962, little was known about the life cycle of the virus or its ability to cause disease. An animal model of disease was needed to understand how the virus causes disease and to develop antiviral compounds to target the virus life cycle. We adapted the virus by serial-passage in lung tissues from mice deficient in interferon receptors. Using the adapted virus, we established a model of respiratory disease where the virus was able to replicate and cause moderate damage to the lung tissue. We created a separate model of disease where the virus caused paralysis and mortality in infected mice, similar to symptoms seen in infected children. Lastly, we evaluated several antiviral compounds to determine if they were able to protect the mice from virus replication and mortality. Guanidine was able to reduce the amount of virus in each tissue as well as protect mice from paralysis and mortality. In addition, human intravenous immunoglobulin (hIVIG), a mixture of pooled antibodies from human donors, did not reduce the amount of virus in the lungs, but did protect mice from paralysis and mortality.

The intimate relationship between vegetation and soil has long been a subject of interest. Ecologists, soil surveyors, and ranchers have recognized that vegetation differences are often accompanied by variation in soil types.

Undesirable and variable behavior in mares related to the estrous cycle is a common issue reported in the equine industry, especially for mares in a performance setting. These behaviors can interfere with, as well as decrease, overall performance. The objective of this study was to determine if administration of sixty units of oxytocin once daily for 29 days, regardless of when treatment was initiated during the estrous cycle, would induce prolonged corpus luteum (CL) function in cycling mares. Mares were randomly assigned to two groups: 1) saline-treated control (n=7) and 2) oxytocintreated (n=9). Control mares received 3 cc saline and oxytocin-treated mares received sixty units (3 cc) of oxytocin intramuscularly (IM) for 29 consecutive days. Treatment was initiated in all mares on the same day, independent of the day of the cycle. Jugular blood samples for determination of progesterone concentration were collected three times weekly (M, W, F) for 21 days before treatment was initiated. Beginning on the first day of treatment, blood samples were collected daily for seven days, three times weekly for the remainder of the treatment period, and then three times weekly for 45 days after the last treatment. Mares were considered to have prolonged CL function if serum progesterone remained >1.0 ng/mL for at least 30 days during/after the treatment period. The proportion of mares with prolonged CL function was higher in the oxytocin-treated group compared to the saline-treated group (7/9 vs. 1/7, respectively; P1.0 ng/mL throughout the treatment period and into the post-treatment period. All mares with prolonged CL function maintained elevated progesterone concentrations through at least day 56 of the study. Sixty units of exogenous oxytocin treatment for 29 consecutive days was effective in prolonging CL function as a means of estrus suppression in mares.