Date of Graduation

2017

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Marlon Knights

Committee Co-Chair

Ida Holaskova

Committee Member

Joe Moritz

Committee Member

Kevin Shaffer

Committee Member

Matthew Wilson

Abstract

Reproductive success is essential for high levels of animal productivity. Low fertility has been identified as one of the main constraints hindering the productivity of livestock systems. To address this problem, several tools such as genomic selection and assisted reproductive techniques (ART) have been implemented. Two of the more common ART used to improve reproductive performance are artificial insemination (AI) and embryo transfer (ET). The success of these methods is highly dependent on individual animal characteristics; therefore the ability to select animals that provide high levels of reproductive success is essential. The size of the ovarian antral follicular population (AFP) is directly determined by the antral follicular count (AFC) and can help determine reproductive success in sheep and success in ART in water buffaloes. The circulating levels of anti-mullerian hormone (AMH) have been found to be associated with AFP and may be an important endocrine marker in selection of females of high reproductive potential. In study 1, the effect of breed on AMH and the relationship between AMH and fertility in replacement ewes was evaluated. Katahdin females had a higher A than Dorset/Texel (DT) and Suffolk females. Katahdin females with HIGH AMH had a higher conception rate and lambing to first service than females with LOW AMH. AMH did not affect conception rate and lambing to first service in DT females. Katahdin females that conceived and lambed to the first service had a higher concentration of AMH. Concentration of AMH did not differ among DT females. In study 2, the concentration of AMH and the relationship between AMH and age, follicular growth and development in water buffaloes was evaluated. The within cow repeatability of the concentration of AMH was 0.97. AMH generally increased until ten years of age and then decreased. The mean concentration of AMH was 194 pg/ml. Females with HIGH AMH had more large follicles and follicles with a greater diameter than females with LOW AMH. In study 3, the relationship between circulating AMH and type of FSH preparation (FSHp and Folltropin) on follicular growth and development and ovulatory response in water buffaloes was evaluated. In animals treated with FSHp, HIGH systemic AMH was associated with more small follicles. AMH had no effect on small follicles in animals treated with Folltropin V. In animals treated with Folltropin V, HIGH AMH was associated with a higher ovulation rate. AMH had no effect on the number of ovulated follicles in animals treated with FSHp. These studies provide evidence that AMH varies among breeds of sheep, with age in water buffaloes and may be a reliable endocrine marker to predict ovarian response to superovulation treatments in water buffaloes.

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