This project aims to determine the effects of package type (pellet vs straw) and concentration of spermatozoa at the time of freezing by examining sperm characteristics (morphology, motility, acrosome integrity and viability). It will establish how we can optimise the quality of frozen-thawed ram semen destined for AI.
These outcomes will create benefits for the wool industry through improved and more consistent AI success. Ultimately, providing recommendations and criteria to the industry on how they can minimise the damage of cryopreservation on ram spermatozoa to greatly optimise sperm quality and improve male fertility.
Semen will be collected from 3 rams on four separate occassions (n=12) at The University of Sydney Animal Reprduction Unit. Semen will be diluted with industry standard cryodiluent (Triladyl) to 800 x 10^6, 600 x 10^6, 400 x 10^6, and 200 x 10^6 sperm/ml and then split to be frozen in straws and pellets (a total of eight treatments/replicate). Upon thawing, semen will be tested for motility (subjective and CASA kinematics), morphology, acrosome integrity, and viability at 0, 2, 4 and 6h of incubation at 37C.
Optimal straw and pellet protocols will be communicated to a commercial sheep artificial breeding company for direct comparison with their current semen processing method on a minimum of 12 processed ejaculates. Straws/pellets from these commercial processed freezes will be transported frozen to The University of Sydney and analysed as above.