LC-MS/MS proteomic dataset of frozen-thawed Guanzhong dairy goat (Capra hircus) semen/spermatozoa comparing a control freezing extender versus the same extender supplemented with 6 uM L-selenomethionine, to identify differentially abundant proteins and pathways linked to cryo-induced stress, ferroptosis-related mechanisms, and post-thaw sperm quality.