ULTRASTRUCTURE OF THE `DECAPITATED SPERM DEFECT' IN GUERNSEY BULLS

Abstract

Summary. Attempts to study the ultrastructure of the `decapitated sperm defect' in ejaculates from sterile Guernsey bulls have so far been a failure because of difficulties in fixation of the separated heads and tails. Fixation of testis and epididymis tissue from a recent typical case, however, gave better results and have confirmed that in the testis most of the heads and tails are still in close contact with each other. The separation takes place in the caput epididymidis. The cause of the defect seems to be localized to structures belonging to the base of the sperm head, especially the implantation groove and the basal plate.