Previous studies of epididymal transit in the pig have had insufficient animal numbers
to provide a comprehensive picture of a continuous process. The present study attempts
to addresses this issue. Radioactively labeled thymidine was infused into the testicular
arteries of 48 sexually rested young adult boars of the Goettingen Miniature Pig breed.
Hemicastrations were performed in random order in 2 animals daily on Days 21-24 following
thymidine injection and in 4 animals daily on Days 25-41 and 43, 45, 47 and 49. Sperm
obtained from 12 epididymal sites between the proximal caput and distal cauda were
autoradiographically examined to record the percentage of labeled sperm and labeling
intensity at different times after thymidine infusion. An initial surge of labeled
spermatozoa emerged in the proximal caput 28 days after thymidine injection. After
2 d labeled sperm had arrived at the distal caput and, after another 2, the bulk of
labeled sperm was found in the corpus. From there the sperm advanced to the transition
of corpus and cauda, where progress was arrested until Dayll. On Day 12, transit was
resumed and by Day 13 sperm had passed through the cauda and vacated the epididymis
via the ductus deferens. (C) 2020 Published by Elsevier Inc.