The Use of Stains to Improve Bovine Embryo Search Times

Thomas Vierhout


During a bovine embryo transfer, the embryos need to be located under a microscope once they have been extracted from a donor cow. Simple and vital stains were used to try to improve visibility of the embryos and shorten the amount of time necessary to find them. A visibility gradient was set up using observable, defining characteristics of the embryos and used to compare the stained with the unstained embryos. The embryos stained with a vital stain, methyl blue, were more visible under challenging circumstances than the unstained. Methyl blue was shown to significantly shorten the time spent searching for the bovine embryos. The short term viability of the stained embryos was tested to determine any deleterious effects of the stain. The stained embryos sustained their viability after five hours. The staining method was determined to be beneficial in the search for bovine embryos, and subsequent steps necessary before use in the field were discussed.