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Optimization of ovarian superstimulation before ovum pick-up and in vitro embryo production in pregnant cattle

Hayden, Cameron
http://rave.ohiolink.edu/etdc/view?acc_num=osu1661120001272212

Abstract Details

2022, Master of Science, Ohio State University, Animal Sciences.
This thesis focuses on the assessment of strategies directed at the optimization of ovum pick-up (OPU) and in vitro embryo production (IVEP) in pregnant cattle. The primary determinants for the success of OPU/IVEP are the number and quality of oocytes recovered after OPU, which in turn are affected by the number and developmental stage in the follicle population from which oocytes are collected. The objectives, therefore, were to: 1) evaluate the effect of use and dose of follicle stimulating hormone (FSH) on ovarian response and IVEP; 2) investigate the effect of synchronization of timing of follicle wave emergence (FWE) among females before ovarian superstimulation on ovarian response and IVEP; and 3) determine the efficacy of various methods for synchronizing FWE. In the first experiment, presented in Chapter 3, pregnant heifers (n = 48) were assigned to receive 0, 160 or 300 mg of porcine FSH (p-FSH) administered in four decreasing doses beginning at time of FWE. Ultrasonography, to evaluate ovarian response preceded OPU, which was performed 40 h after the last p-FSH administration and cumulus oocyte complexes (COC) that were collected were subjected to IVEP procedures. Total number of follicles at OPU and number of both total and viable COCs increased linearly (P < 0.0001) with increasing p-FSH dose. Cleavage percentage, number of cleaved oocytes, blastocyst percentage and number of blastocysts increased linearly (P < 0.0001) with increasing p-FSH dose. In the second experiment, presented in Chapter 4, pregnant heifers (n = 64) were randomly assigned to initiate superstimulatory treatments, consisting of administration of 160 mg of p-FSH, after synchronization of timing of FWE or at random stages of the follicular wave. Synchronization of timing of FWE resulted in a greater (P < 0.01) percentage of medium sized follicles, as well as greater (P < 0.01) cleavage and blastocyst percentage, which subsequently led to an increased (P < 0.01) number of blastocysts produced. In the third experiment, presented in Chapter 5, pregnant heifers (n = 86) were randomly assigned to be administered gonadotropin releasing hormone (GnRH); human chorionic gonadotropin (hCG); follicle ablation (FA); or remain untreated (Control). Ovarian dynamics were evaluated using transrectal ultrasonography. Efficacy of synchronizing the timing of FWE was greater (P < 0.05) for FA and hCG-treated than Control heifers, while there was marginal evidence (P = 0.06) for a difference between GnRH-treated and Control heifers. Conversely, heifers in the FA-treated group had a shorter and less variable (P < 0.05) interval from treatment to FWE than Control, hCG and GnRH-treated heifers. In conclusion, synchronization of timing of FWE and subsequently inducing ovarian superstimulation with exogenous FSH before OPU/IVEP in pregnant cattle improves ovarian response and oocyte developmental competence leading to greater embryo production. Furthermore, synchronization of timing of FWE using hCG or GnRH has similar efficacy as that occurring with FA treatment, however, FA provides a more precise control of follicle development which may prove beneficial for use before ovarian superstimulation and OPU/IVEP.
Alvaro Garcia Guerra (Advisor)
Marco Coutinho da Silva (Committee Member)
James Kinder (Committee Member)
165 p.
Animal Sciences
Bovine, ovarian superstimulation; ovum pick-up; in vitro embryo production; follicle stimulating hormone; follicle wave emergence; pregnant; cattle

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Citations

  • Hayden, C. (2022). Optimization of ovarian superstimulation before ovum pick-up and in vitro embryo production in pregnant cattle [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1661120001272212

    APA Style (7th edition)

  • Hayden, Cameron. Optimization of ovarian superstimulation before ovum pick-up and in vitro embryo production in pregnant cattle. 2022. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1661120001272212.

    MLA Style (8th edition)

  • Hayden, Cameron. "Optimization of ovarian superstimulation before ovum pick-up and in vitro embryo production in pregnant cattle." Master's thesis, Ohio State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=osu1661120001272212

    Chicago Manual of Style (17th edition)

osu1661120001272212
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