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.

We examined the sexual development and insemination capability of boars representing five breeds used at Polish sow insemination stations. The speed of attaining full breeding maturity by the boars and their insemination usefulness was assessed based on the results of experiments analysing age related changes in the physical characteristics of the ejaculates. Directly after sampling, the ejaculates were analysed for the following physical parameters: ejaculate volume, sperm concentration and the percentage of progressively motile spermatozoa per ejaculate. The total number of spermatozoa in the ejaculates and the number of insemination doses obtained from one ejaculate were calculated using SYSTEM SUL v. 6.1 software. The sexual development of boars continues during insemination use, leading to improved ejaculatory performance. The physical parameters of the ejaculate change along with the age of the boar. The Duroc and Hampshire boars represent a pattern of sexual development that is different from that of the PLW, PL and Pietrain males, with an evident earlier termination of growth. The American boars (Duroc and Hampshire) acquire top ejaculatory performance approximately 6 months earlier.

The aim of this study was to compare ejaculates of Duroc and Pietrain boars in terms of sperm morphology characteristics. Analysis was performed on 116 ejaculates collected from 6 Duroc boars and 9 Pietrain boars. The boars selected for examination were young and at the beginning of their reproductive utilization. Ejaculates were collected at monthly intervals over the period of 10 months. Microscopic slides were prepared immediately after collection of ejaculates. The slides were examined to assess the frequency of morphological abnormalities. Moreover, morphometric measurements were taken from 15 randomly selected morphologically normal spermatozoa. Also, conventional evaluation of ejaculates was made following methods used at Polish sow insemination centres. Differences were found in the dimensions and shape between Duroc and Pietrain spermatozoa. Pietrain spermatozoa were characterised by significantly smaller head perimeter compared with Duroc ( P ≤ 0.01). Moreover, Pietrain spermatozoa tails were by 0.8 μm longer ( P ≤ 0.01), and their total sperm length was greater by 0.5 μm compared to Duroc ( P ≤ 0.05) sperm. The volume of Duroc ejaculates was lower but their sperm concentration was greater. The results of the present study contribute to scientific progress as they demonstrate differences in sperm size between boars of different breeds, which may be reflected in different reproductive performances of the boars.

Introduction: The aim of this study was to propose the optimal methodology for stallion semen morphology analysis while taking into consideration the staining method, the microscopic techniques, and the workload generated by a number of samples. Material and Methods: Ejaculates from eight pure-bred Arabian horses were tested microscopically for the incidence of morphological defects in the spermatozoa. Two different staining methods (eosin-nigrosin and eosin-gentian dye), two different techniques of microscopic analysis (1000× and 400× magnifications), and two sample sizes (200 and 500 spermatozoa) were used. Results: Well-formed spermatozoa and those with major and minor defects according to Blom’s classification were identified. The applied staining methods gave similar results and could be used in stallion sperm morphology analysis. However, the eosin-nigrosin method was more recommendable, because it allowed to limit the number of visible artefacts without hindering the identification of protoplasm drops and enables the differentiation of living and dead spermatozoa. Conclusion: The applied microscopic techniques proved to be equally efficacious. Therefore, it is practically possible to opt for the simpler and faster 400x technique of analysing sperm morphology to examine stallion semen. We also found that the number of spermatozoa clearly affects the results of sperm morphology evaluation. Reducing the number of spermatozoa from 500 to 200 causes a decrease in the percentage of spermatozoa identified as normal and an increase in the percentage of spermatozoa determined as morphologically defective.

Experiments were performed on 75 ejaculates obtained from 19 bulls representing different cattle breeds used at the Masovian Centre for Animal Breeding and Reproduction in Łowicz. Fresh ejaculates were measured in respect to their volume and sperm count in the ejaculates was determined. The ejaculates were classified based on the criterion of sperm concentration and divided into five groups. Sperm morphometric measurements were taken from each bull and assessment of semen morphology was done on the basis of examination under a microscope using preparations made from fresh ejaculates. For each slide, morphometric measurements were taken of 15 randomly selected spermatozoa characterised by normal morphology and well visible under the microscope. Additionally, in each preparation morphometry of 500 spermatozoa was evaluated, numbers of spermatozoa with normal morphology and morphological abnormalities were recorded and these were categorized into spermatozoa with major and minor defects. An insignificant correlation was observed between the sperm concentration in the ejaculate and morphological traits, dimensions and shapes of bull spermatozoa. The less concentrated ejaculates contained spermatozoa with a slightly larger head circumference and a more elongated head shape in comparison with the spermatozoa in the more concentrated ejaculates. The highest frequency of morphologically malformed spermatozoa, both in the case of primary and secondary alterations, was observed in ejaculates with sperm concentration of no more than 1000 x 10(3)/mm3.

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).