Influence of semen handling on post-thaw sperm motility

Abstract Text: Artificial insemination allows cattle producers access to the genetic-leading sires in the industry. However, correct methods of thawing frozen semen should be followed to ensure acceptable pregnancy success. Thus the objective of this project was to determine how semen handling during the thawing process can impact different parameters of sperm motility.  Semen from 14 bulls were allotted to 9 treatments: 1) Control (handled correctly; thawed at 36°C for 45 sec and placed into an warmed 36°C AI gun for 1 min), 2) thawed at 22°C, 3) thawed at 13°C, 4) thawed at 38°C, 5) thawed at 33°C, 6) thawed correctly and then placed into a 4°C AI gun, 7) thawed correctly and then placed into a 43°C AI gun, 8) thawed for on 15 sec, or 9) exposed to room temperature for 15 sec before thawing.  After thawing, semen was incubated at 37°C for 20 min and 3 h and then stained with Hoechst 33342 and motility parameters were analyzed using the IVOSII Computer Assisted Sperm Analysis (CASA) system.  Data were analyzed using the mixed procedure of SAS for repeated measures with bull as a random variable.  There was a treatment and time effect on both total motility (P < 0.01) and progressive motility (P < 0.01), and a tendency for a treatment by time interaction (P = 0.08).  Both total and progressive motility decreased with time (P < 0.01), and thawing semen at reduced temperatures (treatment 2 and 3) reduced (P < 0.05) total (15.9% and 12.4%) and progressive (3.9% and 4.3%) motility compared to controls (36% and 13.8%).  Sperm velocity (curvilinear) was influenced by time (P < 0.01), but not treatment or treatment by time (P = 0.95 and 0.45).  Straight line velocity was also influenced by time (P < 0.01), but there was no treatment or treatment by time interaction (P = 0.20 and 0.31).  Both curvilinear and straight line velocity decreased from 20 min to 3 h (P < 0.01).  In conclusion thawing semen at an incorrect temperature had negative effects on sperm motility (total and progressive).  Thus improper thawing of semen could have dramatic negative effects on AI conception rates.

Keywords: Artificial insemination, semen handling, sperm motility