Computer automated morphometric analysis of bull sperm heads

Abstract

Morphological type classification of spermatozoa is an important component of the modern semen evaluation; however, current methods of analysis are subjective and highly variable between technicians. To reduce the subjectivity and thus variability of sperm morphology assessment, computer automated sperm head morphology analysis (ASMA) has been developed. Previous studies have shown the importance of standardizing ASMA procedures to optimize accuracy. The objective of this study was to standardize ASMA procedures for evaluating bull sperm heads. Semen from 10 fertile bulls was used to standardize procedures for optimal analysis of bull spermatozoa. Sample preparation methods, sperm staining methods and microscopic magnifications were compared. Semen samples that were diluted to a standard concentration of 200× 10 6 sperm/ml were more efficiently analyzed than raw samples. A modified GZIN staining procedure, incorporating rose bengal as an acrosomal stain, was used for accurate ASMA at a magnification of × 60. The mean morphometric measurements for all bulls were the area (27.30μM), perimeter (25.36μM), length(8.65μM), width(4.40μM) and width/length (0.50). Within the analyses, coefficients of variation ranged from 3.45% for length to 8.52% for area. The ASMA system correctly digitized sperm heads 97% of the time. Results of this study indicate that bull sperm heads can be accurately analyzed using current standard procedures of ASMA technology.