Morphometric Characteristics of Spermatozoa in the Arabian Horse With Regard to Season, Age, Sperm Concentration, and Fertility

Abstract

One hundred eighty ejaculates were collected from 15 healthy Arabian horses (6–26 years old) for morphometric evaluation of their spermatozoal dimensions. The progressively motile sperm percentage, sperm abnormalities percentage, and sperm cell concentration (×106 sperm/mL) were determined. Stained slides with nigrosin–eosin solution were prepared for sperm morphometric analysis using an eye-piece micrometer. The sperm measurements were sperm head length, head maximum breadth, head base breadth, acrosome length, midpiece and breadth, tail length and breadth, sperm head area, and perimeter. Data were divided according to season, stallions' age, and fertility. Results revealed that mensuration of sperm head length, head maximum breadth, midpiece length, and tail length were 5.96 ± 0.004, 3.06 ± 0.004, 10.17 ± 0.008, and 48.88 ± 0.022 μm, respectively. The head area and perimeter were 14.33 ± 0.022 μm2 and 14.16 ± 0.009 μm, respectively. The total number of sperm per ejaculate in spring and summer was significantly (P < .05) higher than in autumn and winter. The lowest sperm concentration (153.61 ± 26.75 × 106/mL) and the longest head length (6.00 ± 0.01 μm) were found during winter. Sperm head length, head maximum breadth, head base breadth, head area, and perimeter were the lowest in group A (<10 years). Sperm morphometry was highly significantly (P < .001) affected by the stallion. The head maximum breadth, head base breadth, sperm head area, and perimeter were (P < .001) smaller in stallions with high fertility (69%–79%) compared with those of low fertility (50%–59%). In conclusion, stallion sperm morphometry was affected by the season, stallions' age, and stallions. Sperm head maximum breadth, head area, and perimeter were smaller in stallions of high fertilizing capacity.