Abstract: Artificial insemination (AI) is the most widely used biotechnology for genetic improvement through banks of frozen spermatozoa in bull. However, the genetic impact in the AI industry is limited by the efficiencies of semen production, 40% to 50% of viable sperm lose their integrity or functionality during the freezing-thawing process. Based on the literature from home and abroad in recent years, the article explained the effects and mechanism of frozen-thawed on spermatozoa, the influence of seminal plasma on bull frozen sperm quality, the peroxide damage and the protein and gene changes during frozen-thaw. The aim was to provide a reference for research of bull high quality semen and further promote the frozen semen quality.

Key words: bull; semen frozen; damage mechanism; research advances 