Assessment of Novel Semen Evaluation Technologies and Breed Comparisons in Yearling Beef Bulls

Abstract

The objective of this study was to evaluate correlations of sperm quality assessments and breed comparisons as observed during yearling beef bull breeding soundness exams (BSE). Ejaculates were collected via electroejaculation from yearling Charolais (n = 23) and Angus (n = 23) bulls as part of BSE. One veterinarian conducted BSE, and one technician conducted sperm quality assessments. Additional sperm motility analysis was conducted with the iSperm. Ejaculates meeting minimum thresholds for passing a BSE were subjected to flow cytometry. Pearson’s correlation coefficients were determined, and breed comparisons were made using GLIMMIX in SAS. The iSperm analyzer gross and progressive motilities were correlated ( r = 0.30; 0.38; P < 0.001) with the progressive motility assessed by the technician. Neither iSperm ( P = 0.26) nor visual assessment ( P = 0.66) of sperm motility differed between breeds. Bull breed did not influence total percentage of viable cells ( P = 0.83), percentage of viable cells with intact acrosomes ( P = 0.83), or percentage of live sperm cells with positive reactive oxygen species (ROS) status ( P = 0.92). Sperm from Charolais bulls (31.1% ± 3.35) tended ( P = 0.10) to have greater percentage of positive mitochondrial energy potential as compared with Angus bulls (17.6% ± 3.35). Percentage of live spermatozoa with negative ROS status was moderately correlated with the percentage of spermatozoa exhibiting secondary abnormalities ( r = 0.33; P = 0.02). Percentage of live spermatozoa with disrupted acrosomes was strongly correlated ( r = 0.66; P < 0.001) with percentage of live spermatozoa with negative ROS. Percentage of live spermatozoa with positive ROS status was correlated ( r = 0.58; P < 0.001) with percentage of spermatozoa with active mitochondrial membranes. Sperm motility data assessed by the technician and iSperm data are positively correlated, offering producers an on-farm evaluation tool. Though the bull breed had little influence on sperm quality assessments, negative ROS status appears to impair sperm health and function.