+publisher:"Virginia Tech" +contributor:("Lewis, Gregory S.")

Virginia Tech

1. Barahona, Roberto G. Suazo. Intrauterine position in pigs: effects on conceptus development and fetal fluids steroid content.

Degree: MS, Animal Science, 1989, Virginia Tech

URL: http://hdl.handle.net/10919/43288

► The purpose of this study was to investigate the effect of intrauterine position and its possibly resultant steroid differential on conceptus growth and steroid content… (more)

Subjects/Keywords: Swine; LD5655.V855 1989.B273

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APA (6^th Edition):

Barahona, R. G. S. (1989). Intrauterine position in pigs: effects on conceptus development and fetal fluids steroid content. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/43288

Chicago Manual of Style (16^th Edition):

Barahona, Roberto G Suazo. “Intrauterine position in pigs: effects on conceptus development and fetal fluids steroid content.” 1989. Masters Thesis, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/43288.

MLA Handbook (7^th Edition):

Barahona, Roberto G Suazo. “Intrauterine position in pigs: effects on conceptus development and fetal fluids steroid content.” 1989. Web. 16 Apr 2021.

Vancouver:

Barahona RGS. Intrauterine position in pigs: effects on conceptus development and fetal fluids steroid content. [Internet] [Masters thesis]. Virginia Tech; 1989. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/43288.

Council of Science Editors:

Barahona RGS. Intrauterine position in pigs: effects on conceptus development and fetal fluids steroid content. [Masters Thesis]. Virginia Tech; 1989. Available from: http://hdl.handle.net/10919/43288

Virginia Tech

2. Krisher, Rebecca L. Gene injection in the bovine: effect of time of microinjection and nuclear transfer technologies.

Degree: PhD, Animal Sciences, Dairy, 1994, Virginia Tech

URL: http://hdl.handle.net/10919/38296

► Four experiments were conducted to investigate methods of producing transgenic bovine embryos entirely in vitro. Experiment 1 examined the effect of DNA microinjection at 11,… (more)

▼ Four experiments were conducted to investigate methods of producing transgenic bovine embryos entirely in vitro. Experiment 1 examined the effect of DNA microinjection at 11, 15 and 19 h after fertilization (haf) on survival rate and DNA detection frequency by polymerase chain reaction (PCR). There was no difference in transgene detection frequency between treatments (53% at 11; 50% at 15; 48% at 19 haf). Of all injected embryos developing to the morula or blastocyst stage after 7 d in culture, 89% tested positive for the presence of the transgene by PCR. Greater developmental efficiencies can be obtained when injection is performed early in pronuclear formation (7% (11/161) at 11; 4% (61159) at 15; 1 % (1/165) at 19 haf; p<0.05). Experiment 2 examined the effect of microinjection of DNA into the germinal vesicle (gv) of bovine oocytes on subsequent development and detection of the transgene. Injection of the transgene into the gv reduced developmental rates compared to controls (control=23% (89/384); non-injected=9% (23/250); GV injected=5% (12/259); p<O.05). Transgene detection frequency was 64% (37/58). Injection of bovine oocytes before fertilization results in viable embryos containing the transgene, although at low frequencies. Experiment 3 was designed to examine whether the frequency of microinjected DNA detection by peR In whole bovine embryos would decline over a 21 d culture period. At d 0, the transgene was detected in 100% (46/46) of embryos analyzed. At d 7, detection frequency was 84% (51/62) in viable embryos, at d 14 49% (18/37), and at d 21 38% (3/8). DNA detection frequency in microinjected bovine embryos by PCR analysis does not give a reliable indication of live transgenic birth rates until after 14 d in culture. Experiment 4 examined microinjected bovine embryos for their potential use as donor embryos in nuclear transfer, or cloning. There was no difference in development between embryos cloned from microinjected donor embryos and those from control donor embryos (injected=11 % (37/377); control=9% (7/81); p>0.05). Of the embryos developing from microinjected donors, 32% (12/37) were PCR positive. Microinjected embryos can be successfully used in a nuclear transfer program to produce more viable embryos, and the resulting embryos may be more reliably screened by PCR. The efficiency of producing viable bovine embryos positive for the injected gene may be increased by performing microinjection early in pronuclear formation, and entering the resulting embryos into a nuclear transfer program. Advisors/Committee Members: Gwazdauskas, Francis C. (committeechair), Akers, Robert Michael (committee member), Lewis, Gregory S. (committee member), Pearson, Ronald E. (committee member), Saacke, Richard G. (committee member), Wong, Eric A. (committee member), Vinson, William E. (committee member).

Subjects/Keywords: Cell nuclei; LD5655.V856 1994.K757

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APA (6^th Edition):

Krisher, R. L. (1994). Gene injection in the bovine: effect of time of microinjection and nuclear transfer technologies. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/38296

Chicago Manual of Style (16^th Edition):

Krisher, Rebecca L. “Gene injection in the bovine: effect of time of microinjection and nuclear transfer technologies.” 1994. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/38296.

MLA Handbook (7^th Edition):

Krisher, Rebecca L. “Gene injection in the bovine: effect of time of microinjection and nuclear transfer technologies.” 1994. Web. 16 Apr 2021.

Vancouver:

Krisher RL. Gene injection in the bovine: effect of time of microinjection and nuclear transfer technologies. [Internet] [Doctoral dissertation]. Virginia Tech; 1994. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/38296.

Council of Science Editors:

Krisher RL. Gene injection in the bovine: effect of time of microinjection and nuclear transfer technologies. [Doctoral Dissertation]. Virginia Tech; 1994. Available from: http://hdl.handle.net/10919/38296

Virginia Tech

3. Ellis, Steven E. Mechanisms Controlling Ductal Morphogenesis in the Ruminant Mammary Gland.

Degree: PhD, Dairy Science, 1998, Virginia Tech

URL: http://hdl.handle.net/10919/30728

► Basic research into the histology, endocrine control, and local regulation of prepuberal ruminant mammogenesis was conducted to provide a better understanding of this important developmental… (more)

▼ Basic research into the histology, endocrine control, and local regulation of prepuberal ruminant mammogenesis was conducted to provide a better understanding of this important developmental period. Histologic features of prepuberal ruminant mammary parenchymal morphogenesis were examined in tissue samples taken from ewe lambs at 2 (n = 5), 3 (n = 15), 6 (n = 26), 9 (n = 7), 12 (n = 5), and 13 wk (n = 20), and from Holstein heifers at 4 (n = 1) and 6 mo (n = 2). Examination of approximately 8000 histologic sections revealed that mammary parenchymal morphogenesis in sheep and cattle occurs through the proliferation of highly arborescent ductal structures embedded in a dense stroma. These observations contrast strongly with models of mammogenesis based on murine mammary development. The formation of luminal spaces and the expansion of ducts also differed from murine mammogenesis models. Luminal spaces were shown to develop through a progressive separation of opposing sides in initially solid ductal structures. Likewise, our investigation of prepubertal ovine mammogenesis revealed that parenchymal weight, 3H-thymidine labeling, stromal weight, and parenchymal DNA were all unaffected by ovariectomy (P > 0.05), in marked contrast to the dramatic reduction in mammary development following ovariectomy in rats, mice, and heifers. Responsiveness to exogenous estrogen (0.1 mg/kg) was demonstrated by increased 3H-thymidine labeling (P < 0.05) in both intact and ovariectomized lambs. Three dimensional collagen gel cultures of bovine mammary organoids from the peripheral (OUTER) and medial (INNER) parenchymal zones were used to characterize the proliferative and morphogenetic responses to local-acting growth factors. The proliferation of OUTER cells was 2 to 3 times greater than INNER cells (P < 0.0001) in response to IGF-I stimulation. Dramatic differences in the morphology of INNER and OUTER organoids were also observed. INNER cells grew into smooth-edged colonies when treated with heifer serum but stellate colonies when treated with other mitogens. OUTER cells grew into stellate colonies regardless of mitogen treatment. These investigations highlight the fact that a great deal more research into the basic physiology of prepuberal ruminant mammogenesis is required and that dogma developed in murine model systems may not be applicable to ruminant mammary physiology. Advisors/Committee Members: Akers, Robert Michael (committeechair), Caceci, Thomas (committee member), Lewis, Gregory S. (committee member), Gwazdauskas, Francis C. (committee member), McFadden, T. B. (committee member), Vinson, William E. (committee member).

Subjects/Keywords: Prepuberal Mammogenesis; Ovariectomy; Collagen Gel Cultures

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APA (6^th Edition):

Ellis, S. E. (1998). Mechanisms Controlling Ductal Morphogenesis in the Ruminant Mammary Gland. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/30728

Chicago Manual of Style (16^th Edition):

Ellis, Steven E. “Mechanisms Controlling Ductal Morphogenesis in the Ruminant Mammary Gland.” 1998. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/30728.

MLA Handbook (7^th Edition):

Ellis, Steven E. “Mechanisms Controlling Ductal Morphogenesis in the Ruminant Mammary Gland.” 1998. Web. 16 Apr 2021.

Vancouver:

Ellis SE. Mechanisms Controlling Ductal Morphogenesis in the Ruminant Mammary Gland. [Internet] [Doctoral dissertation]. Virginia Tech; 1998. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/30728.

Council of Science Editors:

Ellis SE. Mechanisms Controlling Ductal Morphogenesis in the Ruminant Mammary Gland. [Doctoral Dissertation]. Virginia Tech; 1998. Available from: http://hdl.handle.net/10919/30728

Virginia Tech

4. Dalton, Joseph C. Factors Important to the Efficiency of Artificial Insemination in Single-Ovulating and Superovulated Cattle.

Degree: PhD, Dairy Science, 1999, Virginia Tech

URL: http://hdl.handle.net/10919/27139

► To identify factors important to the efficiency of artificial insemination in cattle, four studies were conducted. In the first study, the addition of cream to… (more)

▼ To identify factors important to the efficiency of artificial insemination in cattle, four studies were conducted. In the first study, the addition of cream to the inseminate was used in an attempt to increase accessory sperm number. On d 6 after insemination, 60 embryos were evaluated. The addition of cream to the inseminate had no effect on accessory sperm number. In the second study, cryopreserved semen of a marked bull (spermatozoa exhibiting a semi-flattened anterior head) was matched with semen from an unmarked bull (conventional sperm head shape) to determine competitively the effect of a deep uterine insemination on accessory sperm number. Forty embryos were recovered 6 d after insemination and the ratio of accessory sperm observed was different: 62:38 for unmarked semen in the uterine body and marked semen in the uterine horn, and 72:28 for unmarked semen in the uterine horn and marked semen in the uterine body (P < .05). In the third study, superovulated cows were utilized to determine the effect of artificial insemination time on fertilization status and accessory sperm number. Cows were inseminated once at 0 h (n=10), 12 h (n=10), or 24 h (n=10) after the first standing event. On d 6 after insemination, 529 embryos(ova) were recovered. Fertilization rates were 29% (0 h); 60% (12 h); and 81% (24 h)(P < .01). Percentages of embryos with accessory sperm were: 5 (0 h); 8 (12 h); and 41(24 h) (P < .01). In the fourth study, three experiments utilizing superovulated cows were conducted to provide a basis for distinguishing unfertilized ova from very early embryonic death. In Exp. 1, recovered d 6 unfertilized ova were classified morphologically as either: 1) typical, 2) satellite, or 3) fragmented. In Exp. 2, recovered d 6 unfertilized ova from the third study were classified morphologically, and typical ova were fixed. In Exp. 3, ultrastructural features of preovulatory, tubal-stage, and typical d 6 unfertilized ova were investigated. Preovulatory ova revealed normal ultrastructure; tubal-stage ova exhibited evidence of degeneration; typical d 6 ova were degenerated and contained no discernable organelles. The first three studies support the use of accessory sperm evaluation as an alternative measure of fertility. The final study provides a basis from which future embryologists may distinguish fertilization failure from very early embryonic death. Advisors/Committee Members: Saacke, Richard G. (committeechair), Nebel, Raymond L. (committee member), Bailey, Thomas L. (committee member), Lewis, Gregory S. (committee member), Grayson, Randolph Larry (committee member).

Subjects/Keywords: accessory sperm; artificial insemination; cattle; superovulation

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APA (6^th Edition):

Dalton, J. C. (1999). Factors Important to the Efficiency of Artificial Insemination in Single-Ovulating and Superovulated Cattle. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27139

Chicago Manual of Style (16^th Edition):

Dalton, Joseph C. “Factors Important to the Efficiency of Artificial Insemination in Single-Ovulating and Superovulated Cattle.” 1999. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/27139.

MLA Handbook (7^th Edition):

Dalton, Joseph C. “Factors Important to the Efficiency of Artificial Insemination in Single-Ovulating and Superovulated Cattle.” 1999. Web. 16 Apr 2021.

Vancouver:

Dalton JC. Factors Important to the Efficiency of Artificial Insemination in Single-Ovulating and Superovulated Cattle. [Internet] [Doctoral dissertation]. Virginia Tech; 1999. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/27139.

Council of Science Editors:

Dalton JC. Factors Important to the Efficiency of Artificial Insemination in Single-Ovulating and Superovulated Cattle. [Doctoral Dissertation]. Virginia Tech; 1999. Available from: http://hdl.handle.net/10919/27139

Virginia Tech

5. Wulster, Meghan Carole. Estradiol-17beta-Oxytocin Induced Cervical Dilation in Sheep: Application to Transcervical Embryo.

Degree: MS, Animal and Poultry Sciences, 1997, Virginia Tech

URL: http://hdl.handle.net/10919/36942

► Experiments were initiated to determine whether exogenous estradiol-17beta (E2) and oxytocin (OT) can be used to dilate the cervix and improve transcervical embryo transfer (ET)… (more)

▼ Experiments were initiated to determine whether exogenous estradiol-17beta (E2) and oxytocin (OT) can be used to dilate the cervix and improve transcervical embryo transfer (ET) procedures for sheep. However, there was concern that the E2-OT treatment may alter luteal function and that embryo quality would decrease as the superovulatory response to FSH increased. In Exp. 1, 32 ewes were assigned to a 2 x 2 factorial array of treatments. On d 7, ewes received an i.v. injection of either 100 micrograms of E2 in 5 mL of 1:1 ethanol:saline or 5 mL of 1:1 ethanol:saline; 12 h later, ewes received i.v. injection of either 400 USP units of OT or saline. Jugular blood was collected on d 7, 8, 9, 10, 12, 14, 16, and 18. Progesterone concentrations were unaffected by the treatments. Experiment 2 was conducted to determine the dose of pFSH needed to induce approximately six corpora lutea (CL). Ten-day Norgestomet implants inserted between d 8-12 of the estrous cycle were used to synchronize estrus in Hampshire and Hampshire x Dorset ewes (n = 23). Ewes received a total of either 0, 18, 27, or 36 mg of pFSH, which was injected i.m. at -24, -12, 0, 12, 24, and 36 h relative to implant removal. The dose at each respective time was 19.4, 19.4, 16.7, 16.7, 13.9, and 13.9% of the total. Ewes received 400 IU of PMSG i.m. at -24 h. The CL were counted laparoscopically on d 6 (d 0 = estrus). Number of CL increased linearly (P < .01) with dose of pFSH; there were 1.8, 3.6, 6.3, and 11.2 CL/ewe, respectively. Experiment 3 was conducted to determine the effect of the E2-OT treatment, mode of transfer or the interaction of E2-OT treatment x mode of transfer on embryo survival and development. Experiment 3 was conducted over two breeding seasons and across two trials. In the first trial ewes were assigned to one of three randomized treatments. Procedural limitations that were later overcome prevented a true 2 x 2 factorial design; therefore, transcervical transfer without hormonal treatment was excluded in the first trial. In the second trial, ewes were assigned to a 2 x 2 factorial array of treatments. On d 6 of pregnancy, embryos rating a fair or better were transferred into recipients either transcervically or laparoscopically. Recipients were administered either an E2 (d 6) - OT (d 7) treatment or an ethanol:saline-saline treatment following the same protocol as in Exp. 1. Embryos were recovered on d 12 in Trial 1 and d 14 in Trial 2. Embryos were evaluated morphologically for development and ranked on a scale of one to four; one represented no development and four represented development to the morphological stages associated with the day of collection. The treatments did not affect the percentage of embryos recovered after transfer or the percentage of embryos that showed some developed. However, there was an effect of mode of transfer on mean rank of embryo development; embryos transferred laporscopically developed further than embryos transferred transcervically (P < .01). This may have been an artifact of a technician… Advisors/Committee Members: Lewis, Gregory S. (committeechair), Saacke, Richard G. (committee member), Knight, James W. (committee member).

Subjects/Keywords: Embryo Transfer; Oxytocin; Sheep

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APA (6^th Edition):

Wulster, M. C. (1997). Estradiol-17beta-Oxytocin Induced Cervical Dilation in Sheep: Application to Transcervical Embryo. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/36942

Chicago Manual of Style (16^th Edition):

Wulster, Meghan Carole. “Estradiol-17beta-Oxytocin Induced Cervical Dilation in Sheep: Application to Transcervical Embryo.” 1997. Masters Thesis, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/36942.

MLA Handbook (7^th Edition):

Wulster, Meghan Carole. “Estradiol-17beta-Oxytocin Induced Cervical Dilation in Sheep: Application to Transcervical Embryo.” 1997. Web. 16 Apr 2021.

Vancouver:

Wulster MC. Estradiol-17beta-Oxytocin Induced Cervical Dilation in Sheep: Application to Transcervical Embryo. [Internet] [Masters thesis]. Virginia Tech; 1997. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/36942.

Council of Science Editors:

Wulster MC. Estradiol-17beta-Oxytocin Induced Cervical Dilation in Sheep: Application to Transcervical Embryo. [Masters Thesis]. Virginia Tech; 1997. Available from: http://hdl.handle.net/10919/36942

Virginia Tech

6. Hensley, Erika L. Induced Cervical Dilation in Sheep: Evaluation of the Effects on Fertilization Rates and Embryonic Development.

Degree: MS, Animal and Poultry Sciences, 1999, Virginia Tech

URL: http://hdl.handle.net/10919/44194

► Experiments were conducted to determine the effects of a treatment used to dilate the cervix for transcervical AI and embryo transfer on pregnancy or fertilization… (more)

Subjects/Keywords: Cervix; Oxytocin; Sheep

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hensley, E. L. (1999). Induced Cervical Dilation in Sheep: Evaluation of the Effects on Fertilization Rates and Embryonic Development. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/44194

Chicago Manual of Style (16^th Edition):

Hensley, Erika L. “Induced Cervical Dilation in Sheep: Evaluation of the Effects on Fertilization Rates and Embryonic Development.” 1999. Masters Thesis, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/44194.

MLA Handbook (7^th Edition):

Hensley, Erika L. “Induced Cervical Dilation in Sheep: Evaluation of the Effects on Fertilization Rates and Embryonic Development.” 1999. Web. 16 Apr 2021.

Vancouver:

Hensley EL. Induced Cervical Dilation in Sheep: Evaluation of the Effects on Fertilization Rates and Embryonic Development. [Internet] [Masters thesis]. Virginia Tech; 1999. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/44194.

Council of Science Editors:

Hensley EL. Induced Cervical Dilation in Sheep: Evaluation of the Effects on Fertilization Rates and Embryonic Development. [Masters Thesis]. Virginia Tech; 1999. Available from: http://hdl.handle.net/10919/44194

Virginia Tech

7. Faber, Eric G. Follicular dynamics, estradiol-17[beta] concentrations, and luteinizing hormone release following norgestomet implant insertion during estrus synchronization with melengestrol acetate.

Degree: MS, Animal and Poultry Sciences, 1995, Virginia Tech

URL: http://hdl.handle.net/10919/45059

► The objective of this experiment was to determine whether norgestomet implant insertion following melengestrol acetate (MGA) administration altered LH pulse frequency and follicular dynamics.… (more)

Subjects/Keywords: follicles; LD5655.V855 1995.F334

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APA (6^th Edition):

Faber, E. G. (1995). Follicular dynamics, estradiol-17[beta] concentrations, and luteinizing hormone release following norgestomet implant insertion during estrus synchronization with melengestrol acetate. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/45059

Chicago Manual of Style (16^th Edition):

Faber, Eric G. “Follicular dynamics, estradiol-17[beta] concentrations, and luteinizing hormone release following norgestomet implant insertion during estrus synchronization with melengestrol acetate.” 1995. Masters Thesis, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/45059.

MLA Handbook (7^th Edition):

Faber, Eric G. “Follicular dynamics, estradiol-17[beta] concentrations, and luteinizing hormone release following norgestomet implant insertion during estrus synchronization with melengestrol acetate.” 1995. Web. 16 Apr 2021.

Vancouver:

Faber EG. Follicular dynamics, estradiol-17[beta] concentrations, and luteinizing hormone release following norgestomet implant insertion during estrus synchronization with melengestrol acetate. [Internet] [Masters thesis]. Virginia Tech; 1995. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/45059.

Council of Science Editors:

Faber EG. Follicular dynamics, estradiol-17[beta] concentrations, and luteinizing hormone release following norgestomet implant insertion during estrus synchronization with melengestrol acetate. [Masters Thesis]. Virginia Tech; 1995. Available from: http://hdl.handle.net/10919/45059

Virginia Tech

8. Wulster-Radcliffe, Meghan Carole. The Mechanism of Action of Exogenous PGF2alpha in Clearance of Nonspecific Uterine Infections in Sheep and Pigs.

Degree: PhD, Animal and Poultry Sciences, 2000, Virginia Tech

URL: http://hdl.handle.net/10919/37670

► Six experiments were conducted to determine the mechanism of action of exogenous PGF2alpha on the clearance of uterine infections in sheep and pigs. The first… (more)

Subjects/Keywords: Lutalyse; pigs; uterine infections; sheep

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APA (6^th Edition):

Wulster-Radcliffe, M. C. (2000). The Mechanism of Action of Exogenous PGF2alpha in Clearance of Nonspecific Uterine Infections in Sheep and Pigs. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/37670

Chicago Manual of Style (16^th Edition):

Wulster-Radcliffe, Meghan Carole. “The Mechanism of Action of Exogenous PGF2alpha in Clearance of Nonspecific Uterine Infections in Sheep and Pigs.” 2000. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/37670.

MLA Handbook (7^th Edition):

Wulster-Radcliffe, Meghan Carole. “The Mechanism of Action of Exogenous PGF2alpha in Clearance of Nonspecific Uterine Infections in Sheep and Pigs.” 2000. Web. 16 Apr 2021.

Vancouver:

Wulster-Radcliffe MC. The Mechanism of Action of Exogenous PGF2alpha in Clearance of Nonspecific Uterine Infections in Sheep and Pigs. [Internet] [Doctoral dissertation]. Virginia Tech; 2000. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/37670.

Council of Science Editors:

Wulster-Radcliffe MC. The Mechanism of Action of Exogenous PGF2alpha in Clearance of Nonspecific Uterine Infections in Sheep and Pigs. [Doctoral Dissertation]. Virginia Tech; 2000. Available from: http://hdl.handle.net/10919/37670

Virginia Tech

9. Harper, Allen F. An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows.

Degree: PhD, Animal Science, 1992, Virginia Tech

URL: http://hdl.handle.net/10919/39434

► The effects of dietary folic acid supplementation on serum folate status, conceptus development and reproductive performance in gilts and sows was investigated in a series… (more)

▼ The effects of dietary folic acid supplementation on serum folate status, conceptus development and reproductive performance in gilts and sows was investigated in a series of experiments. The specific objectives of the study were to: 1) to study the serum folates profile following rapid consumption of a single meal containing different levels of supplemental folic acid; 2) to study the effects of maternal folic acid supplementation on conceptus survival, growth and development prior to mid-gestation in gilts and sows; and 3) to study the effects of multiple levels of dietary folic acid supplementation on sow reproductive performance over four successive parities. In the first experiment (Chapter III), gilts fed a single, rapidly consumed meal, had a rapid increase in serum folates concentration during the first hour postprandial. Within eight hours after feeding, serum folates in the gilts had returned to near prefeeding levels. The results also suggest that supplementing the diet with increasing levels of folic acid over a range of 0 to 4 ppm results in more rapid postprandial uptake and elimination of folic acid from general circulation. In the second experiment (Chapter IV), supplementing the diet of first parity and third parity breeding sows with 2 ppm folic acid had no effect on litter size at day 45 of gestation. However, several measurements associated with placental and fetal growth were increased with folic acid supplementation. Results of a fifth parity trial with four levels of supplemental folic acid were variable and inconclusive. The implications of increased placental and fetal growth up to day 45 of gestation in the first and third parity sows is discussed. In the third experiment (Chapter V), a decline in serum folate concentration in pregnant sows from mating to mid- to late gestation was clearly demonstrated. Supplementing the sow's diet with folic acid over a range of 0 to 4 ppm resulted in a linear increase in serum folate concentration at mating, during gestation and at weaning. However, under the conditions of this experiment, folic acid supplementation had no significant effect on sow reproductive performance. Advisors/Committee Members: Blodgett, Dennis J. (committee member), Lewis, Gregory S. (committee member), Wood, Cynthia M. (committee member), Lindemann, M. D. (committeecochair), Kornegay, Ervin T. (committeecochair).

Subjects/Keywords: Folic acid; Swine Reproduction; LD5655.V856 1992.H376

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APA (6^th Edition):

Harper, A. F. (1992). An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/39434

Chicago Manual of Style (16^th Edition):

Harper, Allen F. “An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows.” 1992. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/39434.

MLA Handbook (7^th Edition):

Harper, Allen F. “An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows.” 1992. Web. 16 Apr 2021.

Vancouver:

Harper AF. An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows. [Internet] [Doctoral dissertation]. Virginia Tech; 1992. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/39434.

Council of Science Editors:

Harper AF. An assessment of the effects of dietary folic acid supplementation on serum folates status, conceptus development and reproductive performance in gilts and sows. [Doctoral Dissertation]. Virginia Tech; 1992. Available from: http://hdl.handle.net/10919/39434

Virginia Tech

10. Seals, Richard. Prostaglandins Modulate the Uterine Response to Infectious Bacteria in Postpartum and Estrous Cyclic Ewes.

Degree: PhD, Animal and Poultry Sciences, 2000, Virginia Tech

URL: http://hdl.handle.net/10919/27345

► The uterine immune system is down regulated when exposed to P4. Five experiments were conducted to determine the in vivo and in vitro role(s) of… (more)

▼ The uterine immune system is down regulated when exposed to P4. Five experiments were conducted to determine the in vivo and in vitro role(s) of P4 and prostaglandins in immune function(s) associated with uterine infections. In Exp. 1, postpartum ewes (d 0 = parturition) were supplemented with either OIL or P4 (beginning on d 10) or were SHAM or OVEX. Vena caval blood and lymphocytes were collected on d 14, and 16 to 19. All ewes received intrauterine inoculations of bacteria on d 15 and uteri were collected on d 20. Ewes receiving P4 developed infections. Lymphocytes were incubated with mitogens, PGE2, indomethacin (INDO; a PG synthesis inhibitor) or both in a 3 x 2 x 2 arrangement. Concanavalin A-stimulated blastogenesis in P4-OVEX ewes and PGE2 and PGE2+INDO treated lymphocytes was inhibited (P < .05). Cyclic ewes in their follicular or luteal phase received either intrauterine inoculations of saline or bacteria, vena caval blood was collected for 3 d, and uteri were collected. Lymphocytes were incubated with mitogens, PGE2 (Exp. 2), PGF2alpha (Exp. 3) and(or) INDO in a 3 x 2 x 2 arrangement. Only luteal phase ewes that received bacteria developed infections. In Exp. 2, Con A- and LPS-stimulated blastogenesis was greater for luteal than for follicular phase ewes. T lymphocyte proliferation was inhibited in ewes inoculated with bacteria. T lymphocyte proliferation tended to be higher (P = .09) when incubated with INDO. In Exp. 3, T lymphocyte proliferation in response to PGF2alpha was greater for follicular than for luteal phase ewes. Neutrophils were lower in ewes inoculted with bacteria. In Exp. 4 and 5, uteri of luteal-phase (d 6) ewes were inoculated with bacteria. Ewes received either 15 mg of Lutalyse or saline on d 9, and uteri were collected on d 11. Lutalyse reduced P4, tended to decrease neutrophils, allowed ewes to clear infections, and had no effect on blastogenesis. Methods for modulating uterine prostaglandins seem to reduce susceptibility to uterine infections. Advisors/Committee Members: Sponenberg, Daniel Phillip (committee member), Elgert, Klaus D. (committee member), Hohenboken, William D. (committee member), Knight, James W. (committeecochair), Lewis, Gregory S. (committeecochair).

Subjects/Keywords: uterine infections; prostaglandins; sheep; cattle; lymphocytes

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APA (6^th Edition):

Seals, R. (2000). Prostaglandins Modulate the Uterine Response to Infectious Bacteria in Postpartum and Estrous Cyclic Ewes. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27345

Chicago Manual of Style (16^th Edition):

Seals, Richard. “Prostaglandins Modulate the Uterine Response to Infectious Bacteria in Postpartum and Estrous Cyclic Ewes.” 2000. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/27345.

MLA Handbook (7^th Edition):

Seals, Richard. “Prostaglandins Modulate the Uterine Response to Infectious Bacteria in Postpartum and Estrous Cyclic Ewes.” 2000. Web. 16 Apr 2021.

Vancouver:

Seals R. Prostaglandins Modulate the Uterine Response to Infectious Bacteria in Postpartum and Estrous Cyclic Ewes. [Internet] [Doctoral dissertation]. Virginia Tech; 2000. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/27345.

Council of Science Editors:

Seals R. Prostaglandins Modulate the Uterine Response to Infectious Bacteria in Postpartum and Estrous Cyclic Ewes. [Doctoral Dissertation]. Virginia Tech; 2000. Available from: http://hdl.handle.net/10919/27345

Virginia Tech

11. Fortin, Suyapa. Relationships among progesterone, estradiol-17β, 13, 14-dihydro-15-keto-prostaglandin F₂α and prostaglandin F₂α in intact ewes around the time of luteolysis.

Degree: MS, Animal Science, 1991, Virginia Tech

URL: http://hdl.handle.net/10919/46031

► The exact mechanisms controlling uterine secretion of prostaglandin F₂α (PGF₂α) are not known. This study (Experiments 1, 2 and 3) was conducted to evaluate the… (more)

▼ The exact mechanisms controlling uterine secretion of prostaglandin F₂α (PGF₂α) are not known. This study (Experiments 1, 2 and 3) was conducted to evaluate the relationships of progesterone and estrogen to changes in 13,14-dihydro-15-keto-prostaglandin F₂α (PGFM) and PGF₂α in ewes. Experiment 1 was designed to determine whether a radioimmunoassay (RIA) for progesterone would detect pessary-released 6α-methyl-17α-hydroxy-progesterone (MPA; n=3) and oral 17α-acetoxy-6-methyl-16-methylene-4, 6-pregnadiene-3, 20 dione (MGA; n=3) in blood plasma of ovariectomized ewes. Neither progestogen treatment interfered with the RIA. Experiment 2 was conducted to answer the question: Do MPA-containing pessaries delay luteolysis in intact ewes? Ewes were treated with MPA containing (n=10) or blank pessaries (controls; n=8) from d 7 and until d 18 of the estrous cycle for control and until d 22 for MPA-treated ewes; d 0 was the day of estrus. Blood samples were collected from the jugular vein throughout the experiment. Pessaries containing MPA did not affect the timing of luteolysis (d 15.4 ± .2), but they prolonged (P<.O5) the interestrous interval (17.5 d for control vs 24.1 d for MPA-treated ewes). Experiment 3 was designed to study the relationships among progesterone, estrogen, PGFM and PGF₂α in ewes. Ewes were treated with MPA-containing (n=7; 60 mg), progesterone-containing (n=8i 45 mg) or blank pessaries (n=8) from d 7 until d 20 of the estrous cycle. From d 14 and continuing until 24 h after estrus, jugular and vena caval blood samples were collected during two sampling periods daily. Plasma was assayed for progesterone, estrogen, PGFM and PGF₂α. Treatment did not affect the profiles of change in concentration of progesterone, PGFM and jugular PGF₂α, but treatment affected (P < .05) estrogen and vena caval PGF₂α profiles. Overall, treatment affected (P < .05) the mean concentrations of estrogen, progesterone, PGFM and PGF₂α. sampling site (jugular vs. vena cava) affected (P < .0001) the mean concentration of progesterone, estrogen and PGF₂α, but site did not affect PGFM concentrations. Hormonal relationships associated with changes in release of PGF₂α were evaluated. Estrogen seemed to be the primary hormone controlling PGF₂α release. In conclusion, MPA treatment did not delay the timing of luteolysis, but it increased the interestrous interval. Of the compounds measured, estrogen accounted for the greatest proportion of the variation in PGF₂α release in ewes around the time of luteolysis. Advisors/Committee Members: Lewis, Gregory S. (committeechair), Hohenboken, William D. (committee member), Knight, James W. (committee member).

Subjects/Keywords: Luteinizing hormone; LD5655.V855 1991.F679

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Fortin, S. (1991). Relationships among progesterone, estradiol-17β, 13, 14-dihydro-15-keto-prostaglandin F₂α and prostaglandin F₂α in intact ewes around the time of luteolysis. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/46031

Chicago Manual of Style (16^th Edition):

Fortin, Suyapa. “Relationships among progesterone, estradiol-17β, 13, 14-dihydro-15-keto-prostaglandin F₂α and prostaglandin F₂α in intact ewes around the time of luteolysis.” 1991. Masters Thesis, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/46031.

MLA Handbook (7^th Edition):

Fortin, Suyapa. “Relationships among progesterone, estradiol-17β, 13, 14-dihydro-15-keto-prostaglandin F₂α and prostaglandin F₂α in intact ewes around the time of luteolysis.” 1991. Web. 16 Apr 2021.

Vancouver:

Fortin S. Relationships among progesterone, estradiol-17β, 13, 14-dihydro-15-keto-prostaglandin F₂α and prostaglandin F₂α in intact ewes around the time of luteolysis. [Internet] [Masters thesis]. Virginia Tech; 1991. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/46031.

Council of Science Editors:

Fortin S. Relationships among progesterone, estradiol-17β, 13, 14-dihydro-15-keto-prostaglandin F₂α and prostaglandin F₂α in intact ewes around the time of luteolysis. [Masters Thesis]. Virginia Tech; 1991. Available from: http://hdl.handle.net/10919/46031

Virginia Tech

12. Jabbar, Ghulam. Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes.

Degree: MS, Animal and Poultry Sciences, 1993, Virginia Tech

URL: http://hdl.handle.net/10919/43419

► Two commercially available progestogen products for cattle, melengestrol acetate (MGA) and norgestomet (SMB) , were evaluated for their ability to induce synchronized estrus in… (more)

▼ Two commercially available progestogen products for cattle, melengestrol acetate (MGA) and norgestomet (SMB) , were evaluated for their ability to induce synchronized estrus in anovulatory ewes. Seasonally anestrous ewes (n=232; determined by blood serum progesterone concentration) of mixed breeding were randomly assigned within broad age groups to one of seven treatments: 1) control (C); 2) MGA only (OMGA); 3) MGA + zeranol (RMGA); 4) MGA + PG-600 (PMGA; 400 IU pregnant mare's serum gonadotropin + 200 IU human chorionic gonadotropin in a 5 mL dose); 5) 5MB only (OSMB); 6) 5MB + zeranol (RSMB); and 7) 5MB + PG-600 (PSMB). Beginning 10 d before breeding, OMGA, RMGA, and PMGA ewes were fed .3 mg MGA/d provided through a mixture of shelled com and a commercially prepared pelleted supplement containing MGA. Concomitantly, OSMB, RSMB, and PSMB ewes were given a 3 mg norgestomet implant inserted subcutaneously on the back of the ear. Immediately preceding initiation of the MGA and 5MB treatments, RMGA and RSMB ewes were given a single i.m. injection of 2.5 mg zeranol. At the end of the 10-d treatment period, MGA feeding was discontinued and the norgestomet implants were removed. Concomitantly, PMGA and PSMB ewes were given a single i.m. injection of PG-600 (5 mL). All treatment groups were combined into one breeding group on May 4, 1992, with a ram to ewe ratio of 1: 17 for a 30-d breeding period. Mating to synchronized estrus was greater (P < .0001) for progestogentreated ewes. Within progestogen treatments, more (P < .000 1) 5MB ewes were marked within the first 5 d of breeding than MGA ewes. Overall, there were no treatment differences in estrus response for the 30-d breeding period. Blood serum samples collected during the first 14 d of breeding were analyzed for progesterone as an indicator of corpora lutea formation. Even though a large proportion of C ewes displayed luteal activity, only 12 % exhibited behavioral estrus within the first 17 d of breeding. Progestogen treated ewes exhibited a shorter mean interval (P < .0001) from ram introduction to lambing. Fertility and prolificacy were not different for C, MGA, or 5MB ewes. Of the two progestogen treatments used alone, lambing rate was 85 and 59 % (P < .03) for OMGA and OSMB ewes, respectively. Ewes plimed with zeranol before MGA or 5MB treatment exhibited similar levels of fertility and intervals from ram introduction to lambing compared with ewes receiving an injection of PG- 600 after progestogen treatment. These data indicate that progestogen products commercially available for cattle may be useful in enhancing out-of-season breeding performance in sheep. Advisors/Committee Members: Umberger, Steven H. (committeechair), Lewis, Gregory S. (committee member), Notter, David R. (committee member).

Subjects/Keywords: Progestational hormones; Synthetic.; LD5655.V855 1993.J222

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Jabbar, G. (1993). Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/43419

Chicago Manual of Style (16^th Edition):

Jabbar, Ghulam. “Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes.” 1993. Masters Thesis, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/43419.

MLA Handbook (7^th Edition):

Jabbar, Ghulam. “Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes.” 1993. Web. 16 Apr 2021.

Vancouver:

Jabbar G. Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes. [Internet] [Masters thesis]. Virginia Tech; 1993. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/43419.

Council of Science Editors:

Jabbar G. Melengestrol acetate and norgestomet for the induction of synchronized estrus in seasonally anovular ewes. [Masters Thesis]. Virginia Tech; 1993. Available from: http://hdl.handle.net/10919/43419

Virginia Tech

13. Degelos, Suzanne Denise. Separation of abnormal spermatozoa from semen produced by bulls with impaired testicular thermoregulation.

Degree: PhD, Animal Sciences, Dairy, 1995, Virginia Tech

URL: http://hdl.handle.net/10919/38205

Subjects/Keywords: spermatogenesis; LD5655.V856 1995.D444

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Degelos, S. D. (1995). Separation of abnormal spermatozoa from semen produced by bulls with impaired testicular thermoregulation. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/38205

Chicago Manual of Style (16^th Edition):

Degelos, Suzanne Denise. “Separation of abnormal spermatozoa from semen produced by bulls with impaired testicular thermoregulation.” 1995. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/38205.

MLA Handbook (7^th Edition):

Degelos, Suzanne Denise. “Separation of abnormal spermatozoa from semen produced by bulls with impaired testicular thermoregulation.” 1995. Web. 16 Apr 2021.

Vancouver:

Degelos SD. Separation of abnormal spermatozoa from semen produced by bulls with impaired testicular thermoregulation. [Internet] [Doctoral dissertation]. Virginia Tech; 1995. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/38205.

Council of Science Editors:

Degelos SD. Separation of abnormal spermatozoa from semen produced by bulls with impaired testicular thermoregulation. [Doctoral Dissertation]. Virginia Tech; 1995. Available from: http://hdl.handle.net/10919/38205

Virginia Tech

14. Custer, Edward E. Differential effect of melengestrol acetate or progesterone-releasing intravaginal devices on follicular development, progesterone and estradiol-17β concentrations and patterns of luteinizing hormone release during the bovine estrous cycle.

Degree: PhD, Animal Science, 1992, Virginia Tech

URL: http://hdl.handle.net/10919/38836

Subjects/Keywords: Progestational hormones.; LD5655.V856 1992.C879

Record Details Similar Records Cite « Share

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Custer, E. E. (1992). Differential effect of melengestrol acetate or progesterone-releasing intravaginal devices on follicular development, progesterone and estradiol-17β concentrations and patterns of luteinizing hormone release during the bovine estrous cycle. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/38836

Chicago Manual of Style (16^th Edition):

Custer, Edward E. “Differential effect of melengestrol acetate or progesterone-releasing intravaginal devices on follicular development, progesterone and estradiol-17β concentrations and patterns of luteinizing hormone release during the bovine estrous cycle.” 1992. Doctoral Dissertation, Virginia Tech. Accessed April 16, 2021. http://hdl.handle.net/10919/38836.

MLA Handbook (7^th Edition):

Custer, Edward E. “Differential effect of melengestrol acetate or progesterone-releasing intravaginal devices on follicular development, progesterone and estradiol-17β concentrations and patterns of luteinizing hormone release during the bovine estrous cycle.” 1992. Web. 16 Apr 2021.

Vancouver:

Custer EE. Differential effect of melengestrol acetate or progesterone-releasing intravaginal devices on follicular development, progesterone and estradiol-17β concentrations and patterns of luteinizing hormone release during the bovine estrous cycle. [Internet] [Doctoral dissertation]. Virginia Tech; 1992. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/10919/38836.

Council of Science Editors:

Custer EE. Differential effect of melengestrol acetate or progesterone-releasing intravaginal devices on follicular development, progesterone and estradiol-17β concentrations and patterns of luteinizing hormone release during the bovine estrous cycle. [Doctoral Dissertation]. Virginia Tech; 1992. Available from: http://hdl.handle.net/10919/38836

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