|WONDERLY, JESSICA - University Of Wyoming|
|KOEPKE, KALLI - University Of Wyoming|
|ALEXANDER, BRENDA - University Of Wyoming|
Submitted to: Research Day Abstracts: Regional Universities Research Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/7/2017
Publication Date: N/A
Technical Abstract: Artificial insemination (AI) is not readily utilized with sheep because of a lack of knowledge and infrastructure. Therefore, we investigated the effects of the timing of AI with a synchronized estrous on fertility and the impact of cryopreservation diluents on post-thaw sperm quality. The estrous cycle of 80 ewes were synchronized using progesterone-containing controlled internal drug releasing devices (CIDR) and ovulation was induced with PMSG. Ewes were inseminated nonsurgically 47 to 53 hours following CIDR removal using frozen-thawed semen. The fertility was determined at the time of lambing. In a separate experiment, semen was collected and cryopreserved using 200 mM Tris, 300 mM Tris, or skim milk extenders and analyzed using resazurin dye and computer assisted sperm analysis to assess the metabolism and motility of the sperm, respectively. Sperm frozen in 200 or 300 mM Tris had higher (P=0.04) metabolic activity after thawing than sperm preserved in skim milk. Proportions of motile sperm were similar (P>0.05) at thaw regardless of the extender, but curvilinear velocity was greater (P=0.04) in sperm extended in 200 or 300 mM Tris at 15 min. Sperm head movement was greater (P<0.01) for samples frozen with 200 mM Tris extender. The AIs resulted in 15% fertility (12 of 80 lambing) and evaluation of the frozen-thawed sperm indicated that 200 mM Tris is an acceptable extender that enables increased metabolic activity and motility. Future research is warranted to find an optimal AI protocol and time to be used in conjunction with the 200 mM Tris extender.