Do parameters of seminal quality correlate with the results of on-farm inseminations in rabbits?

This study was conducted to determine if different sperm characteristics correlate with the in vivo fertility of rabbit sperm. A total of 2,765 heterospermic inseminations were performed in commercial rabbitries using 50-pooled samples of fresh semen. Sperm motility and morphological evaluations were performed on each of the heterospermic pooled samples to asses the seminal quality, and the percentage of kindling rate (76.2%) and number of kits born alive (9.3) were recorded. Sperm motility parameters, assessed using a computer-assisted sperm analysis (CASA) system (Sperm Class Analyzer, Microptic, Barcelona, Spain), were: average path velocity, curvilinear velocity, straight-line velocity, linearity, amplitude of lateral head displacement, beat cross-frequency, wobble and percentage of total motile spermatozoa. Morphological analyses included the percentage of sperm with a normal apical ridge, the percentage of sperm with cytoplasmatic droplets and the percentage of abnormal sperm. Significant correlations were observed between kindling rate and the percentage of total motile cells (r=0.31; P<0.05), linearity index (r=-0.32; P<0.05) and the percentage of abnormal sperm in the sample (r=-0.32; P<0.05). Regression models including motility and the morphological parameters explained 45% of the variation in kindling rate. These results indicate that motility parameters, determined by CASA systems, in combination with sperm morphology analyses can provide some information about the fertilizing potential of rabbit sperm.