Bull field fertility differences can be estimated with in vitro sperm capacitation and flow cytometry

Introduction This study evaluated whether post in vitro capacitation changes sperm could be used to estimate field fertility differences between bulls. Methods Frozen-thawed semen from five bulls (two four ejaculates per bull) previously identified as high (48.1% and 47.7%), intermediary (45.5%) or low (40.7% 43.1%) fertility, based on pregnancy AI (P/AI), were for total progressive motility, plasma membrane integrity (viability), acrosome (viable with an intact disrupted acrosome), reactive oxygen species (ROS; viable ROS+ ROS-), mitochondrial energy potential, zinc signatures (signatures 1-to-4) CD9 protein populations at pre-wash post-wash (only motility), h0 (diluted non-capacitation media), h0, CM, h3, h6, h24 after dilution media (CM) incubation 37ºC. Data analyzed using the GLIMMIX procedure repeated measures SAS bull, time interaction fixed effects. Results Bull by was significant (P≤0.03) viability, acrosome, signature 3. There tended (P=0.06) a bull 1+2 combined. Time (P≤0.003) all analyses, except ROS- (P=0.12). effect of (P≤ 0.03) 1, 2 1+2, CD9- dead CD9+. High had greater (P≤0.04) percentages sperm, compared decreased (P≤0.05) percentage CD9+ Viable differed (P=0.02) differ amongst bulls; however, association not observed. positive correlation P/AI (P=0.04), there viability (P=0.10), (P=0.10). Discussion In summary, CM flow cytometry analyses seems promising vivo