Effect of sire and extender on sperm motility and share of live or dead sperm in bulls’ fresh ejaculate and in AI doses after thawing
The objectives were to evaluate the effects of sire and content of fresh or ionised egg yolk in extenders on sperm motility and share of live and dead sperm in collected ejaculate, in thawed artificial insemination (AI) doses, and during thermodynamic testing compared to extenders not containing egg yolk. Ejaculates were collected once a week from 4 Holstein bulls. Each of the 20 ejaculate samples from each bull was diluted with 4 different extenders. AndroMed and Bioxcell (no egg yolk) and Triladyl and Optidyl (fresh, ionised egg yolk) were used. A total of 640 AI doses were analysed. The volume of samples, sperm concentration, and percentage of motile spermatozoa were evaluated after collection, as was sperm motility after thawing of AI doses and during thermodynamic testing. Percentages of live and dead sperm were also evaluated. The data set was analysed using SAS/STAT 9.1 (SAS Institute Inc., Cary, NC, USA). The results confirmed significant ( P<0.05–0.01) between-sire differences in the volume, density, and activity of sperm as well as in share of live and dead sperm after collection; in decline of sperm motility in the fresh ejaculate, after thawing, and during the entire thermodynamic test, as well as in the share of live and dead sperm after thawing. The extenders ranked by sperm motility are: Optidyl, Triladyl, AndroMed, and Bioxcell, demonstrating the higher quality of AI doses produced using egg yolk extenders. Differences in sperm motility were significant ( P<0.05–0.01) during the entirety of thermodynamic testing. Egg yolk extenders had a significantly ( P<0.05–0.01) higher percentages of live sperm after thawing.