Date of Award

1984

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

A total of 402 bovine embryos, non-surgically collected on day 6.5-7.5 after estrus, were utilized in evaluation of fluorescein diacetate (FDA) for estimating embryo viability in vitro and to investigate the effect of Bovine Viral Diarrhea (BVD) Virus on embryonic development during in vitro culture. Fluorescent assessment, using UV microscopy (440-480 nm) of embryos after staining in FDA (2.5 (mu)g/ml phosphate buffered saline: PBS), was found to be a rapid, non-toxic and accurate method for evaluation of viability. Embryos with highest fluorescent scores (Score = 4) prior to culture developed at the highest rate (95.7%), while embryos with no fluorescence (score = 0) did not develop. Significant correlations were found between morphological grading and fluorescent scores (r = .71), although FDA was more sensitive in estimating positive development. The investigation of the effect of BVD virus on development of bovine embryos was divided into three studies: (1) BVD virus cultured with live and dead embryos each with and without zona pellucida (four treatments), (2) Micro-injection of BVD virus directly into the blastocele of blastocysts and (3) transfer of BVD virus-exposed embryos into recipient cows. In the first study, live embryos (with and without a zona pellucida) assessed by FDA, developed at normal rates when exposed to BVD virus, showing that embryonic development was independent of the zona pellucida. Microinjection of BVD virus (Study 2) did not reduce in vitro development (91.7%) as compared with control medium-injected blastocysts (85.0%) or non-injected controls (88.3%). In vitro development was 75 and 71 percent for control and BVD virus-exposed embryos, respectively (Study 3). Pregnancy rates were 20.0 and 13.3 percent for control and BVD virus-exposed embryos at 65 days post-transfer. Embryonic mortality was higher in recipients transferred with BVD virus-exposed embryos (5 of 30, 16.7%) compared to controls (3 of 30, 10%); however, this difference was not statistically significant. (Abstract shortened with permission of author.).

Pages

187

Share

COinS