Trans-scrotal ultrasonography and testicular fine-needle aspiration cytology in the evaluation of ram sperm production

The aim of this study was to assess the predictive value of trans-scrotal ultrasonography and testicular fine-needle aspiration cytology for sperm production in rams. Ultrasonographic examination and testicular fine-needle aspiration cytology were performed on 18 adult rams of proven fertility. Semen was collected twice using electroejaculation with an interval of 1 week, then rams were slaughtered and epididymal spermatozoa were collected. Kinetic analysis of post-thawed semen was performed using a Computer-Assisted Sperm Analysis. Rams were divided in four groups on the base of testicular appearance at ultrasonography. Data were analyzed using one-way ANOVA, and Pearson correlation indexes were calculated to identify correlation among the considered parameters. The best echogenicity score group had a higher Spermatic Index (SI) and a higher semen production than the worst group (P = 0.047 for electroejaculation; P = 0.033 for epididymal spermatozoa). Several cytological parameters were correlated with sperm production: secondary spermatocytes with electroejaculation collection (0.703; P = 0.007), spermatogonia (−0.746; P < 0.001) and SI (0.667; P = 0.003) with epididymal collection. In conclusion trans-scrotal ultrasonography and testicular fine-needle aspiration can add useful information about breeding soundness examination in ram.