Embryo development, In vitro fertilization, Bull fertility, Polyspermy, Proteomics Project description: The correlation between sperm traits, fertilization and embryonic development outcomes were investigated by means of functional in vitro assays and mass spectrometry-based proteomics experiments. Spermatozoa from four independent bulls, as well as approx.. 20 cells at 2-cell embryonic stages and full blastocysts (approx. 250 cells) derived from in vitro fertilization of oocytes with spermatozoa from these foru bulls were analyzed by MS-based proteomics.