Analyses of Morphological and Morphometrical Deviations of Bull Spermatozoa by Computer Assisted Semen Analysis Technique

Abstract

To eliminate the subjectivity inherent in conventional methods, morphology evaluation of spermatozoa by morphometry using CASA technique was undertaken in bulls. In this study, 1219 properly digitized spermatozoa, 616 and 603 sperm for 2 clinically normal Jersey bulls identified by scanning the sperm slides prepared from 19 ejaculates were used for morphological and morphometric analysis by CASA technique. The total percentage of sperm abnormalities recorded was 24.4%, of which, the occurrence of tail abnormalities was more often than head and head and tail (in combination). The total and head abnormalities showed significant (p≤0.05) differences between bulls. Among the tail abnormalities the incidence of coiled tail was most frequent followed by bent tail and absent tail. The morphometric characteristics viz. major axis (μm), minor axis (μm), elongation (%), head area (μm2), perimeter (μm) and tail length (μm) were recorded as 9.53, 4.73, 49.5, 35.7, 23.7 and 61.14, respectively. The between bull variations for major axis, elongation, head area, perimeter and tail length were reflected in the morphological differences as well. The incidence of head abnormalities due to higher morphometric values was significantly (p≤0.05) more than abnormalities due to lower and/or higher and lower morphometric values. CASA technique facilitates identification of even small but significant variations in sperm head morphomtrey and certain types of morphological deviations namely total and head abnormalities between clinically normal bulls, which encourages further studies to explore the difference in fertility if any, between bulls.