Association between sperm morphology and sperm count of boar semen

The number of spermatozoa in the ejaculate is important for its quality and that of the sperm contained in it. The number of ejaculated spermatozoa is also associated with sperm dimensions. The aim of this study was to assess the morphological structure of sperm and the frequency of morphological abnormalities in sperm on the ejaculation performance of boars, measured as the total number sperm per ejaculate. The study was conducted using 648 ejaculates collected from 31 Large White boars and 30 Landrace boars. All ejaculates were analysed for basic physical characteristics and the frequency of sperm with morphological abnormalities. In addition, morphometric measurements of the sperm were made and used to calculate their shape indexes. As a result of our study it was noted that sperm from ejaculates with the most spermatozoa have shorter heads with a smaller area than sperm from ejaculates with a small or intermediate number of spermatozoa. Landrace boars produce semen of better quality, with a smaller percentage of sperm with major abnormalities, and the differences between the breeds increase with the number of spermatozoa in the ejaculate. The sperm from Landrace boars have larger heads and longer flagella than the sperm from Large White boars. The differences in sperm dimensions between breeds decrease as the total number of spermatozoa in the ejaculate increases. The number of spermatozoa in the ejaculate was shown to influence the dimensions of the sperm. The effect of the number of ejaculated sperm on ejaculate characteristics and sperm morphology depends on the breed of the male.