Effect of Breeding Season on the Kinematic Parameters and Morphology of Ram’ Sperm from Synthetic Population Bulgarian Milk Sheep Breed

1 Bulgarian Academy of Sciences, Institute of Biology and Immunology of Reproduction, BG - 1113 Sofia, Bulgaria
2 Institute of Animal Science, BG - 2232 Kostinbrod, Bulgaria


ABADJIEVA, D., M. CHERVENKOV, R. STEFANOV, N. METODIEV, E. KISTANOVA, D. KACHEVA and E. RAYCHEVA, 2014. Effect of breeding season on the kinematic parameters and morphology of ram’ sperm from synthetic population Bulgarian milk sheep breed. Bulg. J. Agric. Sci., 20: 967-972


The aim of this study was the investigation of the breeding season effect on the kinematic and main spermatological parameters of the rams from Synthetic Population Bulgarian Milk sheep breed (SPBM), new Bulgarian breed certificated in 2005. The experiment was carried out with seven rams. Two consecutive ejaculates from each ram were obtained by artificial vagina before and during the breeding campaign (n=28). Overall sperm motility and the individual kinematic parameters of motile spermatozoa were assessed by the computer-aided sperm analysis system Sperm Class Analyzer (SCA). The sperm morphology was estimated after sperm blue stain and calculated as a percent of abnormal cells among 100 sperm cells from several fields on the slide. It was found that the ejaculates obtained from SPBM rams during the breeding season had better features of sperm motion kinetics. The values of the velocity parameters (P< 0.05), motility (P< 0.05), and percentages of spermatozoa with rapid (P< 0.01) and medium (P< 0.001) speed were higher than those from the ejaculates collected before the breeding season. Minor and not significant changes in the kinematic parameters of motile spermatozoa in consecutive ejaculates were observed. No significant differences were established in morphological status of spermatozoa in nonbreeding and breeding season. It seems that the better sperm motility kinematic parameters during the breeding season ensure the higher sperm fertility and success on the future insemination.

Key words: rams, spermatozoa, velocity, motility, morphology
Abbreviations: SPBM: Synthetic Population Bulgarian Milk sheep breed; SCA: Sperm Class Analyzer; VCL: curvilinear velocity; VSL: straight-line velocity; VAP: average path velocity; LIN : linearity; STR : straightness; ALH: amplitude of lateral head displacement; BCF: beat cross frequency; WOB : wobble

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