title: A comparison of duck and chicken egg yolk for cryopreservation of stallion sperm.
abstract: OBJECTIVE
  Duck and chicken egg yolk were compared for their protective effects against cold shock during the cryopreservation of stallion sperm in a lactose-EDTA-glycerol cryodiluent.
  
  
  METHODS
  A completely randomised design was used. Procedure Ejaculates from five stallions (n = 14 ejaculates) were split and diluted to either 20 or 200 x 10(6) sperm/mL in a lactose-EDTA extender containing either duck or chicken egg yolk. The extended semen was then frozen in liquid nitrogen. The percentage of sperm total motility and forward progressive motility were assessed before freezing and at 0 and 1 hr after thawing. Morphology data were also collected at 0 and 1 hr post thaw.
  
  
  RESULTS
  Total and forward progressive motility were higher when the sperm were frozen in the presence of duck rather than chicken egg yolk. Furthermore, the total and forward progressive motility and percentage of morphologically normal sperm were higher when frozen at a concentration of 200 than 20 x 10(6)/mL.
  
  
  CONCLUSIONS
  The results of this study demonstrate that the motility parameters of stallion sperm are improved when the semen is frozen in lactose EDTA extender supplemented with duck egg yolk rather than chicken egg yolk. Moreover, sperm motility and the percentage of morphologically normal sperm were higher after freezing at a concentration of 200 x 10(6)/ml rather than 20 x 10(6)/ml.
authors.affiliation: Faculty of Veterinary Science, The University of Sydney, NSW 2006. jclulow@vetsci.usyd.edu.au
authors.forename: J R
authors.initials: JR
authors.lastname: Clulow
authors.forename: W M C
authors.initials: WM
authors.lastname: Maxwell
authors.forename: G
authors.initials: G
authors.lastname: Evans
authors.forename: L H A
authors.initials: LH
authors.lastname: Morris
mesh_terms: D000818:Animals; D002645:Chickens; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004372:Ducks; D004530:Egg Yolk / Q000737:chemistry; D006736:Horses / Q000502:physiology*; D008297:Male; D011897:Random Allocation; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013076:Sperm Count / Q000662:veterinary; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology
chemical_list: D003451:Cryoprotective Agents