The correlation between selected computer assisted sperm analysis parameters and bull fertility

Abstract

Computer Assisted Sperm Analysis (CASA) represents an objective, reproducible and reliable method of sperm quality assessment, however, not many reports exist that correlate its accuracy with bull semen fertility. The aim of this study was to evaluate the correlation between selected CASA motility parameters of cryopreserved bull semen and fertility. The total spermatozoa motility (SM %), the progressive spermatozoa motility (PSM %) as well as the percentage of spermatozoa with rapid movement (RAP %) were measured through CASA. All 12 ejaculates were collected from one Holstein Friesian bull. A total of 816 Holstein Friesian cows were used for artificial insemination (AI) and the evaluation of fertility. The fertility success was assessed by pregnancy rates per cycle (PRC %), 90 days after AI of the cows. The sperm variables that were associated with an increase in the PRC were the SM (R2 = 0. 6722), the PSM (R2 = 0. 6520) and the RAP (R2 = 0. 7103). RAP had a greater influence (P<0.001) on fertility (PRC), than SM and PSM (P<0.01). The increase of sperm motility parameters (SM, PSM and RAP) led to increased PRC, i.e. to increased fertility.