• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • Tagged with
  • 6
  • 6
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Ovarian synchronization and superstimulation in wood bison (Bison bison athabascae)

Palomino, Jesus Manuel 01 September 2011
For this thesis our objectives were to establish an efficient method of ovarian synchronization and superstimulation in bison, and determine the effects of gonadotropin treatments on oocyte collection efficiency and quality in bison. In the first study we conducted two experiments to develop an efficient protocol for synchronization of follicular wave emergence during the anovulatory season. In Experiment 1, we compared the synchronizing effect of follicular ablation (n = 9) and treatment with 2 mg estradiol (E-) 17β in oil (n = 10), while in Experiment 2, we compared follicular ablation (n = 9) and treatment with 2 mg E-17β + 100 mg progesterone (P4; n = 10). Results showed that the degree of synchrony did not differ between ablation and hormone treatment groups in either Experiment, but follicular wave emergence was more synchronous in both treatment groups compared to the untreated control phase. The second study was conducted to develop an efficient method for ovarian superstimulation and oocyte collection during the anovulatory and ovulatory seasons. During the anovulatory season, one experiment was conducted in two replicates to compare the superstimulatory effect of 2500 IU of eCG (n = 10) given intramuscularly vs two doses of 200 mg of pFSH each (n = 10) given subcutaneously. Additionally, the effect of 25 mg of pLH given 24 hours prior oocyte collection on oocyte quality and collection rate was evaluated for each superstimulatory treatment. Results showed that treatment with pFSH induced a higher superstimulatory response and more cumulus oocyte complexes (COC) collected than did eCG during the anovulatory season. Furthermore, treatment with pLH increased the proportion of expanded COC that were collected with ultrasound-guided follicular aspiration. Two experiments were conducted during the ovulatory season, to develop an efficient protocol for superstimulation and oocyte collection. In Experiment 1, we compared the effect of two intramuscular doses of 200 mg of pFSH in saline (n = 11) vs two intramuscular doses of 200 mg of pFSH in a proprietary slow release formulation (SRF; n = 11). In Experiment 2, we compared the effect of a single dose of 2500 IU eCG intramuscularly vs two doses of 200 mg of pFSH administered subcutaneously. Results showed that a 2-dose regime of pFSH, diluted in either saline or a slow-release formulation induced a similar superstimulatory ovarian response in wood bison, while bison given a single-dose of 2500 IU eCG had a significantly lower ovarian response. In summary, synchronization of follicle wave emergence can be effectively accomplished in wood bison during the anovulatory season and follicular ablation, E-17β and E-17β + P4 treatments all shortened, and decreased the variability in the interval to follicular wave emergence. In addition, oocyte collection by transvaginal ultrasound-guided follicle aspiration from superstimulated bison was feasible and practical. Finally, treatment with pFSH was more effective than eCG to induce ovarian superstimulation for ultrasound-guided follicle aspiration in wood bison during both the anovulatory and ovulatory seasons.
2

Ovarian synchronization and superstimulation in wood bison (Bison bison athabascae)

Palomino, Jesus Manuel 01 September 2011 (has links)
For this thesis our objectives were to establish an efficient method of ovarian synchronization and superstimulation in bison, and determine the effects of gonadotropin treatments on oocyte collection efficiency and quality in bison. In the first study we conducted two experiments to develop an efficient protocol for synchronization of follicular wave emergence during the anovulatory season. In Experiment 1, we compared the synchronizing effect of follicular ablation (n = 9) and treatment with 2 mg estradiol (E-) 17β in oil (n = 10), while in Experiment 2, we compared follicular ablation (n = 9) and treatment with 2 mg E-17β + 100 mg progesterone (P4; n = 10). Results showed that the degree of synchrony did not differ between ablation and hormone treatment groups in either Experiment, but follicular wave emergence was more synchronous in both treatment groups compared to the untreated control phase. The second study was conducted to develop an efficient method for ovarian superstimulation and oocyte collection during the anovulatory and ovulatory seasons. During the anovulatory season, one experiment was conducted in two replicates to compare the superstimulatory effect of 2500 IU of eCG (n = 10) given intramuscularly vs two doses of 200 mg of pFSH each (n = 10) given subcutaneously. Additionally, the effect of 25 mg of pLH given 24 hours prior oocyte collection on oocyte quality and collection rate was evaluated for each superstimulatory treatment. Results showed that treatment with pFSH induced a higher superstimulatory response and more cumulus oocyte complexes (COC) collected than did eCG during the anovulatory season. Furthermore, treatment with pLH increased the proportion of expanded COC that were collected with ultrasound-guided follicular aspiration. Two experiments were conducted during the ovulatory season, to develop an efficient protocol for superstimulation and oocyte collection. In Experiment 1, we compared the effect of two intramuscular doses of 200 mg of pFSH in saline (n = 11) vs two intramuscular doses of 200 mg of pFSH in a proprietary slow release formulation (SRF; n = 11). In Experiment 2, we compared the effect of a single dose of 2500 IU eCG intramuscularly vs two doses of 200 mg of pFSH administered subcutaneously. Results showed that a 2-dose regime of pFSH, diluted in either saline or a slow-release formulation induced a similar superstimulatory ovarian response in wood bison, while bison given a single-dose of 2500 IU eCG had a significantly lower ovarian response. In summary, synchronization of follicle wave emergence can be effectively accomplished in wood bison during the anovulatory season and follicular ablation, E-17β and E-17β + P4 treatments all shortened, and decreased the variability in the interval to follicular wave emergence. In addition, oocyte collection by transvaginal ultrasound-guided follicle aspiration from superstimulated bison was feasible and practical. Finally, treatment with pFSH was more effective than eCG to induce ovarian superstimulation for ultrasound-guided follicle aspiration in wood bison during both the anovulatory and ovulatory seasons.
3

Epidemiology of anthrax outbreaks in wood bison (Bison bison athabascae) of the Mackenzie bison population

2014 December 1900 (has links)
Wood bison (Bison bison athabascae) conservation in Northern Canada is negatively affected by diseases that kill these animals, such as anthrax caused by the bacterium Bacillus anthracis. Although this disease is considered ancient and was identified more than 2000 years ago in Egypt, little is still known about this disease in wild bison, such as why adult males are often predominantly affected and if the reason there are mortalities in some years and not in others is due to environmental, pathogen, or host factors. The overall objective of this thesis was to use descriptive and serological epidemiology to provide evidence needed to enhance our understanding of anthrax in wild wood bison. The first chapter explored the 2012 anthrax outbreak in bison of the Mackenzie bison population using descriptive epidemiology. Field crews discovered 451 bison carcasses during the outbreak. The carcasses were found between late June and early August, and it was estimated that the epidemic peaked between July 13-19 based on the date carcasses were found and the estimated length of time the animal had been deceased. A unique feature of this outbreak compared with the two previous outbreaks in the same population, as well as outbreaks in other wild wood bison herds, is that numerous calves, yearlings and adult females died rather than mostly adult males. Three separate geographic regions were identified by a field wildlife veterinarian, and examined for differences in outbreak characteristics. One region had proportionally more male carcasses than the others, and one had more calf deaths. Lack of complete data made it difficult to ascertain if the outbreak truly started in one of these regions before the others, or if it began simultaneously in all three. The second component of this project used serological epidemiology of anthrax in the Mackenzie bison population to gain an understanding of wood bison exposure to the bacterium. Serological samples were collected through various sources between 1986 and 2009, and later tested for anti-PA antibodies. Of the 278 samples tested, 191 (69%) were positive, indicating previous exposure to B. anthracis. Of the samples with a recorded gender, approximately 18.2% of those from females and 35.5% from males tested positive. The dataset spanned only one anthrax outbreak year in this population of animals, and the year with the highest proportion of positive samples was the year following this known epidemic (1994, 90% positive submissions). Adults had a higher prevalence of being seropositive than any of the other age categories, for both sexes. This research has revealed that in some outbreak years, all age classes and both genders of bison are affected by anthrax unlike in most outbreaks where predominantly adult males succumb to disease. Furthermore, bison are likely exposed to B. anthracis in non-outbreak years, indicating that they either experience subclinical disease or recover from clinical disease.
4

SUPEROVULATION AND EMBRYO COLLECTION IN WOOD BISON (Bison bison athabascae): TOOLS TO PRODUCE DISEASE-FREE EMBRYOS

2015 December 1900 (has links)
Reclamation of Canada’s threatened wood bison (Bison bison athabascae) herd is complicated by cattle diseases. As part of an overall goal to conserve bison genetics, five studies were conducted to develop or adapting present reproductive technologies to produce disease-free in vivo-derived wood bison embryos. In Chapter 4, the efficacy of pLH and hCG for inducing ovulation and whether the effect was related to the size of the dominant follicle at the time of treatment was examined in wood bison during the anovulatory season . Ovulation rate with hCG (94%) was nearly two times greater than with pLH (54%), and bison with a growing follicle of ≥10 mm had a greater ovulatory response than those of 8-9 mm. In Chapter 5, the efficacy of pLH and hCG after superstimulation with single or two doses (48 hours apart) of FSH diluted in 0.5% hyaluronan was determined in wood bison. A greater superovulatory ovarian response was found in cows treated with hCG vs. LH during the anovulatory and ovulatory seasons (6.6 vs. 2.8 and 6.3 vs. 3.8 corpora lutea respectively). In addition, dividing the dose of FSH two resulted in greater superovulatory response in wood bison. However, the number of corpora lutea was still lower than expected as compared to cattle using the same two dose method of superovulation (15 corpora lutea; Tribulo et al., 2012). Therefore, in Chapter 6, the effect of the addition of a low dose of eCG at the end of the superstimulation protocol on ovarian response and embryo quality was examined. Although the number of ova/embryos recovered was higher in this study when compared with previous reports in wood bison, no effect of eCG on the number of corpora lutea and embryo quality was found. In Chapters 5 and 6, the effect of exogenous progesterone on embryo quality in wood bison during the anovulatory season was evaluated. We found that progesterone did not improve the number of freezable embryos in either study. In Chapter 7, the effect of lengthening of FSH treatment protocol on superovulatory response and embryo quality during the ovulatory and anovulatory seasons was examined. There was no effect of lengthening the FSH treatment protocol on ovarian response and embryo quality during the anovulatory season. However, embryo quality and ovulation rate were increased by the lengthened treatment protocol during the ovulatory season. Additionally, more freezable embryos (Grades 1 and 2) were obtained during the ovulatory season (1.8 embryos) vs. the anovulatory season (0.3 embryos). Overall, results confirm that superovulation can be performed in wood bison throughout the year, but a higher number of freezable embryos were obtained during the ovulatory season. The final chapter (Chapter 8) focused in the production of disease-free embryos in wood bison. Following superovulation, in vivo-derived wood bison embryos were exposed in vitro to Brucella abortus biovar 1. After incubation, embryos were submitted to the 10-step washing procedures recommended by the IETS to remove the pathogen. When the washing medium contained antibiotics, 100% Brucella-free embryos were obtained. These findings validate the washing procedures for the production of Brucella-free embryos in wood bison.
5

The impacts of wood bison (Bison bison athabascae) grazing on a sub-hygric shrub meadow plant community type, Mackenzie Bison Sanctuary, Northwest Territories /

Smith, David L. January 1990 (has links) (PDF)
Thesis (M. Sc.)--University of Alberta, 1990. / Submitted to the Faculty of Graduate Studies and Research in partial fulfilment of the requirements for the degree of Master of Science, Department of Botany. Includes bibliographical references. Available also in electronic format on the Internet.
6

LESSONS FROM SCENARIO PLANNING FOR WILDLIFE MANAGEMENT IN THE SOUTHWEST YUKON

2014 January 1900 (has links)
The southwest Yukon social-ecological system (SES) is marked by complex changes, including a climate induced directionally changing landscape, an increasing shift away from traditional subsistence lifestyles, and changing species composition. The addition of “new” ungulate species through human and non-human introductions has spawned many management questions. This study developed qualitative scenarios through a participatory process, utilizing scientific and traditional knowledge from within the social-ecological system’s local context. The study worked with local management groups to address two main objectives: 1.) Collaboratively envision alternate future scenarios with management groups from which to collaboratively develop management goals for wood bison, elk, and mule deer to cope with the changing social and ecological landscape of the southwest Yukon and 2.) Discover resource managers’ and local stakeholders’ perceptions of scenario planning as a method identify wildlife management goals. A series of three workshops with the Alsek Renewable Resource Council, the Yukon Wood Bison Technical Team, and the Yukon Elk Management Planning Team addressed the first objective, while two surveys addressed the second objective. Major findings included southwest Yukon-specific wildlife management goals and considerations for using scenario planning in a wildlife management context. The scenarios themselves warn of plausible events that might unfold, such as novel disease and pest outbreaks. Several participants mentioned that the value attributed to different species will change based on scenario context. This prompts warnings for wildlife managers not to “shut the door” on a species today that may be highly valuable for solving food security challenges of the future. Findings suggest that one of scenario planning’s most significant contribution is a forum for people to share perspectives and develop trust and understanding of one another. All participants valued the holistic and long-term thinking aspects of scenario planning, seeing it as a complementary tool to enhance existing planning processes. Major resource management plans and/or resource development projects in the future should consider using a scenarios approach to better articulated goals in terms of whole system impacts.

Page generated in 0.051 seconds