Comparison of Two Dilution Rates on Canine Semen Quality After Cryopreservation in a Coconut Water Extender

Anim Reprod Sci. 2006 May;92(3-4):384-91. doi: 10.1016/j.anireprosci.2005.05.028. Epub 2005 Jul 7.


The objective of the present study was to evaluate the effect of sperm dilution (one part semen:one part extender or at 200 x 10(6) spermatozoa/mL) using a coconut water extender on the post-thaw sperm quality. Twelve ejaculates were collected from six dogs. Semen was divided into two aliquots, one for dilution one part semen:one part extender (group 1) and another for a concentration of 200 x 10(6) spermatozoa/mL (group 2). Semen was initially extended at 37 degrees C at a proportion of one part semen:half part extender (1:1/2) for group 1 (A-fraction). For group 2, the volume for a concentration of 200 x 10(6) spermatozoa/mL was calculated and a half of this volume was used for the initial dilution (A-fraction, 37 degrees C). Coconut water extender containing 20% egg yolk was used for this initial dilution in both groups. After dilution, the semen was cooled for 40 min in a thermal box (15 degrees C) and for 30 min in a refrigerator. The other half of the extender (B-fraction) containing egg yolk and glycerol (12%) was added to semen in both groups. Subsequently, the final concentration of glycerol in the extender was 6%. Ejaculates were frozen in 0.25 mL straws 5 cm above the surface of liquid nitrogen and stored at -196 degrees C. After 1 week, straws were thawed at 37 degrees C for 1 min and the microscopic criteria were evaluated. The dilution method had no influence on sperm motility, vigor and normal spermatozoa (71.4 compared with 67.7%). There was no effect of dog, ejaculate within male on post-thaw semen quality. Moreover, there was not a male x treatment interaction. Both treatments were efficient in preserving sperm quality.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cocos / chemistry
  • Cryopreservation / veterinary*
  • Cryoprotective Agents / pharmacology*
  • Dogs / physiology*
  • Dose-Response Relationship, Drug
  • Male
  • Semen / cytology
  • Semen Preservation / methods
  • Semen Preservation / veterinary*
  • Sperm Count / standards
  • Sperm Count / veterinary*
  • Sperm Motility / drug effects
  • Spermatozoa / physiology*


  • Cryoprotective Agents