Introduction: The effect of two smear staining methods on the dimensions and shape of sperm cells in the semen of domestic pigs was evaluated. Material and Methods: The studies were carried out on 30 ejaculates collected from 15 boars, which included five Duroc boars, five Pietrain boars, and five hybrid Duroc × Pietrain boars. Each ejaculate was next sampled to make two microscopic slides, of which one was stained with eosin-nigrosin and the other with eosin-gentian dye. In total, 600 measurements of sperm cells were made. Each sperm was measured for the following morphometric parameters: head length, head width, head area, head perimeter, tail length, and the total sperm length. Results: Sperms measured on slides stained with eosin-nigrosin showed lower dimensions as compared with those stained with the eosin-gentian dye method. Sperm stained with eosin-nigrosin had shorter and narrower heads than sperm stained with eosin-gentian dye. The method of staining, therefore, affected not only the dimensions of the sperm, but also the proportions of the dimensions defining the shape of the sperm. Conclusions: The size and shape parameters in porcine sperm may take on different values depending on the method of semen staining. Sperm cells stained with eosin-nigrosin are smaller than the sperm stained with eosin-gentian dye. The sensitivity of the sperm to the type of dye used for the fixation may be associated with genetic factors.

Parameters of sexual activity were determined in 49 young boars used for artificial insemination, four times at three-month intervals. The parameters included the time from entering the arena until mounting the phantom; the time from mounting the phantom until achieving erection; the time from achieving full erection until the start of ejaculation; duration of ejaculation; and the number of times the boar mounted the phantom. Characteristics of the ejaculates were also assessed. The libido parameter associated with the greatest efficacy of artificial insemination was the effectiveness of artificial insemination service, the time from entering the arena until the start of ejaculation. The significance of this trait for predicting ejaculation performance was analysed. The libido characteristics were classified into three categories: boars with a short reaction time to the phantom, boars with an intermediate reaction time, and boars with a long reaction time. For these groups, the characteristics of ejaculates collected at the start of the period during which ejaculates were collected and after three, six and nine months were determined. The sexual experience of boars was not associated with the expression of sexual behaviour because young boars during their first three months of ejaculate collections required less time to initiate ejaculation. The ejaculates with the greatest utility were obtained after six months of service. These ejaculates had the largest volume (255.22 mL), and the most insemination doses could be prepared from these ejaculates. On average, more than 23 insemination doses were prepared from ejaculates collected after six months of semen collections, which is about four doses more than from ejaculates collected at the start of artificial insemination service (p < 0.01).The time from entering the arena to beginning ejaculation can be used to predict a boar’s future libido. A relationship was shown between the level of libido and ejaculate characteristics. The ejaculates of the boars which needed the longest time to begin ejaculation at the start of semen collections had the greatest sperm concentration and number. In group 3, the boars’ejaculates contained about 6–9 × 10⁹ more sperm than the ejaculates of boars from group 1. After six months of the experimental period, the difference was nearly 15 × 10⁹ sperm (p < 0.05), and after nine months, it exceeded 22 × 10⁹ sperm (p < 0.01).

The study involved 50 insemination boars at the age of 8–9 months at the beginning of the study. Each boar was assessed four times for its sexual activity: at the beginning of breeding service and after three, six and nine months into the insemination service. Ejaculates were collected for the purpose of the sexual activity parameters’ assessment. Physical parameters of the ejaculates were subsequently analysed. Pearson’s linear correlation was used to calculate the coefficients of a phenotypic correlation between sexual activity levels and physical parameters of the ejaculates. According to this an appropriate analysis was conducted concerning the changes in boars’ sexual activity throughout their dynamic, sexual development. It was proved, that ejaculate volume depends on the total time of copulation. The highest correlation between ejaculate volume and sexual urge levels was observed in the youngest boars at the beginning of insemination service. The correlation between the ejaculatory efficiency and a boar’s libido changes with age and sexual development. Changes in ejaculatory efficiency are the most dynamic at the age of approx. 1.5 years. At this age ejaculate volume and ejaculate sperm count dynamically increase. The insemination fitness forecasting in case of boars should include libido measurements taken at the beginning of an insemination service – within the first three months. Measurements taken at a more advanced age are of little use for the purpose of ejaculatory efficiency forecasting in case of boars.

Introduction:The aim of this study was to evaluate the dependence between ejaculate traits, sperm morphology, and ejaculate volume in Duroc boars.Material and Methods:The analysis involved 121 ejaculates collected from 12 Duroc boars kept in three artificial insemination centres located in central Poland. Ejaculates were collected manually at one-month intervals, over a period of 10 months. At least 10 ejaculates were collected from each boar. The material was divided by ejaculate volume and each ejaculate was assigned to one of three volume groups: 160 mL and lower, 161–200 mL, and 201 mL and higher. The ejaculates were assessed to identify the basic physical traits and determine the incidence of morphological abnormalities in the spermatozoa, specifying major and minor abnormalities. Furthermore, the morphological structure indices for the spermatozoa were also calculated.Results:In large-volume ejaculates, spermatozoa were more elongated in shape, their heads were more elongated and had the largest flagella. With an increase in the ejaculate volume, sperm concentration in the ejaculate decreased. Moreover, while the total number of sperm in the ejaculate increased, the number of insemination doses obtained from a single ejaculate were higher.Conclusion:The volume of ejaculate has little impact on the occurrence of morphological abnormalities and the size of sperm cells. Ejaculate volume is important for the shape of the sperm cells.

Introduction: Determination of sperm concentration and morphology in ejaculate is essential in evaluating fertility. Sperm shape and dimensions may depend on their concentration in ejaculate. The aim of the study was to evaluate the dependence of Hypor boar morphological and morphometric sperm characteristics on concentration in ejaculate. Material and Methods: The study was conducted on 120 ejaculates from 12 Hypor boars. Depending on sperm concentration, they were put into three groups: low, medium, and high. Ejaculate sperm concentration was determined with the photometric method. Slides were prepared from semen samples which were evaluated for the morphology of spermatozoa. The preparations for morphological analyses were by the eosin-gentian staining method. Results: As the sperm concentration in the ejaculate increased, the length, perimeter, and area of the sperm heads also did. In the ejaculates with higher sperm concentration the sperm heads were rounder. The ratios of head dimensions to tail length or total length were the highest in the sperm from ejaculates with the highest concentrations. The highest percentage of morphologically abnormal sperm was noted in ejaculates with low concentrations. Conclusion: The dimensions and shape of sperm depend on the sperm concentration in the ejaculate. In ejaculates with the highest concentrations, the sperm have larger dimensions. Sperm concentration affects the frequency of morphological anomalies in the spermatozoa.