Degree Type

Thesis

Date of Award

2018

Degree Name

Master of Science

Department

Animal Science

Major

Animal Science

First Advisor

Curtis R. Youngs

Abstract

During the 2016 and 2017 breeding seasons, a total of 462 producer-owned ewes were presented at the Iowa State University large animal hospital for laparoscopic artificial insemination (LAI). A retrospective analysis was performed using these clinical data to investigate factors that potentially influence the success of LAI. Because not all producers provided pregnancy data, only 310 ewes were used for the final analysis. One hundred eighty-eight of 310 ewes (60.6%) became pregnant following LAI, and pregnancy rate was affected (P<0.001) by year. Uterine tone at the time of LAI had no effect (P>0.23) on pregnancy rate. Semen having a post-thaw motility rate of less than 50% produced a lower (P=0.0314) pregnancy rate (29.4%) than semen with post-thaw motility above 65% (pregnancy rate of 60.5%); post-thaw motility between 50-65% was intermediate (pregnancy rate of 54.1%). In one year, there was a tendency (P<0.10) for higher pregnancy rates in ewes whose estrus was synchronized with progesterone for 10 days (52.6%) than in ewes treated for 7 days (31.6%). Results of this study revealed that the degree of uterine tone observed at the time of LAI is not predictive of pregnancy rate and that semen post-thaw motility, as well as the duration of progesterone treatment during synchronization of estrus for LAI, can influence pregnancy outcome resulting from LAI in sheep.

Copyright Owner

Benjamin James Duran

Language

en

File Format

application/pdf

File Size

69 pages

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