Use of Fluorescent Dyes for Observing Bovine Spermatozoa in Opaque Media

Abstract

A method for staining sperm with fluorescent dyes and examination with ultraviolet light is presented. By using this method with semen diluted with opaque media, the spermatozoa were made clearly visible with no interference from fat globules or other extraneous material, and evaluation of sperm motility was readily made. These dyes in concentrations of 1:10,000 to 1:40,000 were nontoxic to the spermatozoa during the 15-min. incubation at 37° C. and caused only a slight reduction in motility after storage at 5° C. for 24 hr. The staining of sperm so that they fluoresce in ultraviolet light was found to make the sperm clearly visible for evaluation of motility in whole milk, yolk-phosphate, or other diluents in which white light illumination does not allow good discrimination between sperm and media. Other possible uses of this procedure also are discussed. © 1959, American Dairy Science Association. All rights reserved.