Effect of Processing Procedures on Motility of Bovine Spermatozoa Frozen in .25-ml Straws

Abstract

One ejaculate from each of six bulls was used in an experiment of factorial design to determine the effects of cooling from 37 to 5 C in .5, 2 or 4 hr and glycerol equilibration at 5 C for 2, 4, 6, 10 or 18 hr on post-thaw motility of spermatozoa frozen in .25-ml Continental⁵ straws. Thawing was by immersion in iced water for 3 min or 75 C water for 7 sec or by rolling straws between the palms of the hands for 50 seconds. Cooling from 37 to 5 C in 2 or 4 hr was superior (P<.05) to cooling in .5 hour. The length of equilibration had no effect (P >.10) on post-thaw spermatozoal motility. Thawing by immersing straws in 75 C water was superior (P<.01) to thawing in iced water or palm thawing, but there was no difference between the latter two methods (P>.05). Optimum post-thaw motility for spermatozoa in straws resulted when spermatozoa were cooled to 5 C in 2 hr followed by 4- or 10-hr equilibration or when cooled in 4 hr followed by 2- or 4-hr equilibration. Results with these four treatments using 75 C thawing were better (P<.01) than when spermatozoa from the same ejaculates were frozen in 1.0-ml glass ampules and thawed in iced water for 10 minutes. A second experiment of factorial design was conducted to evaluate two procedures for treating semen with antibiotics; incubation at 32 C both with and without antibiotics for 0, 15, 30 or 60 min before initial dilution and cooling; and glycerol equilibration for 1, 2, 4, 8 or 16 hours. Neither method of antibiotic addition nor holding time affected (P>.10) post-thaw motility. Equilibration times of 1, 2 and 4 hr were superior (P<.05) to 16 hours. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science