In vitro assessment of sperm from bulls of high and low field fertility

摘要: The aim of this study was to investigate the reasons for differences in field fertility bulls following insemination with frozen-thawed semen. carried out two separate parts over years and comparisons were made between 5 high 4 low Holstein Friesian as determined by their either 90 day non-return rate (Year 1) or calving 2). Two Limousin included Year 1 comparative purposes. ability sperm from each bull penetrate artificial mucus assessed = 7 replicates; 2 replicates). Glass capillary tubes (2 per replicate) filled incubated stained 1% Hoechst 33342 30 min at 37 °C. number subsequently counted 10 mm intervals along tube 40 80 markers. Sperm mitochondrial activity MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) assay (4 replicates year). h °C which absorbance formazan read using a spectrophotometer. viability after thawing live/dead kit 3 A minimum 250 cells replicate classified live dead. Finally, fertilize oocytes vitro develop blastocyst stage embryos (5 year involving 220 306 bull). Data transformation normalize residuals required penetration (square root) IVF (cleavage rate) results (arcsin). mean mark higher (56.0; 95% CI 39.5 75.3) compared (42.9; 29.3 59.1) but difference did not reach formal significance (P 0.09). Fertility status had no effect on reduce (mean 0.34 ± 0.051 0.30 0.044) percentage straw 47.3 5.47 32.4 4.66) respectively. Oocyte cleavage significantly than [76.7% (95% 60.9 89.4) 55.3 40.4 69.7) respectively, P 0.04]. There significant [34.7% 21.1 49.6) 24.2 % 14.1 36.0) bulls, respectively; 0.2]. In conclusion, tended be more effective penetrating have an increased vitro; however, once fertilization occurred subsequent embryo development affected status.