Use of computer-assisted sperm motility assessment and multivariate pattern analysis to characterize ejaculate quality in Mohor gazelles (Gazella dama mhorr): effects of body weight, electroejaculation technique and short-term semen storage

Subjective and objective semen assessments were performed on 18 male Mohor gazelles (Gazella dama mhorr). Sperm motility assessments combined with spe rm plasma membrane and acrosomal integrity evaluations were undertaken as p art of a captive breeding programme. The primary objective was to test meth odology for shortterm preservation of gazelle semen for artificial insemina tion (storage in N-[Tris(hydroxymethyl)methyl]-2-aminoethanesulphonic acid- Tris diluent (TEST) for up to 96 h at 17 degreesC). However, the secondary objective was to investigate phenotypic and genotypic influences on semen q uality within this small population, which was established in 1971 with onl y 12 genetic founders. Sperm motility was measured by computer-assisted sem en assessment and the data were analysed using a pattern analysis technique to detect and quantify naturally occurring sperm subpopulations within the semen samples. Four sperm subpopulations distinguishable by their motion c haracteristics were detected. The relative frequencies of two subpopulation s (population 2: highly motile, non-linear; and population 4: poorly motile , non-linear) in fresh semen were correlated with the maximum voltage used during electroejaculation. The frequency of subpopulation 2 was negatively correlated with maximum voltage (r = -0.875, P < 0.0001) and the frequency of subpopulation 4 was positively correlated (r = 0.727, P < 0.005). The fr equencies of all subpopulations varied significantly among the animals samp led (chi-squared = 2577.6, degrees of freedom = 54, P < 0.0001) and subpopu lation 4 was also correlated with body weight (r = -0.59, P < 0.005). Semen stored at 17 degreesC retained motility, plasma membrane and acrosomal int egrity for 48 h, but these measures decreased thereafter. The frequency of a sperm subpopulation showing uncoordinated but active motility increased s ignificantly over the first 48 h and then decreased.