In the porcine industry, male sperm quality plays a relevant role in the productivity and profitability of the productive system in the tropics. Understanding the factors affecting semen quality is important for optimizing male reproductive efficiency. The present study aimed to evaluate the seminal quality associated with season, breed, age, and sperm counting chamber in boar ejaculates. A total of 22 sexually mature and healthy boars from maternal and sire commercial breeds were utilized as semen donors, with an average age (mean ± standard deviation) of 21.0 ± 7.2 months. The boars were housed individually in well-ventilated pens and fed a standard breeder mix. The boars were grouped according to age into three categories: 24 months, and semen doses were collected from each boar during the dry and rainy seasons. Ejaculates with at least 75 % morphologically normal sperm and more than 8.5 x 109 total sperm per ejaculate were used. The semen doses were analyzed using Computer-Assisted Semen Analysis (CASA; ISAS® v1). The results showed that younger boars (<12 months) exhibited higher progressive and total sperm motility and faster swimming patterns than older boars. The estimation of total motility and fast spermatozoa increased during the rainy season. The kinematic variables showed significant differences (P < 0.05) between the sperm counting chambers. The Duroc and Landrace breeds presented spermatozoa with greater total motility, whereas the terminal sire line breeds showed accelerated linear progressiveness (P < 0.05). Overall, the impact of various factors on seminal and kinematic variables in boar ejaculates, including age, season, genetic breed composition, and sperm counting chamber, enables us to better understand semen quality in boars. This emphasizes the importance of optimizing swine reproductive management practices in sexually active boars.

Introduction. In the dairy industry, frozen-thawed semen is crucial for artificial insemination and genetic improvement of cattle. Objective. To evaluate the variation in the kinematic subpopulation structure of frozen-thawed semen in Jersey and Holstein breeds using a CASA-mot system. Materials and Methods. The study was conducted from April to November 2023, at the Animal Reproduction Laboratory (AndroTEC), located at the Campus Tecnológico Local San Carlos, Alajuela, Costa Rica. Eight animals from the Holstein and Jersey breeds were used, and nine doses of frozen-thawed semen per animal were analyzed for each breed. A total of 72 semen doses from eight bulls (four from each breed) were thawed at 37 °C for 30 s. Sperm motility and kinematic variables were analyzed using CASA-mot (Computer-Assisted Semen Analysis) technology. Results. The Jersey breed presented higher percentages of total motile, progressive motile, and rapid spermatozoa compared to the Holstein breed (P < 0.05). Principal component analysis revealed two significant factors explaining 87.5 % of the total variance in kinematic variables. The kinematic variables between sperm subpopulations (SP) showed differences (P < 0.05) in both breeds. Subpopulation SP2 was the fastest, with higher values for curvilinear speed (VCL), straight-line speed (VSL), and average trajectory speed (VAP) in both Holstein and Jersey bulls. Conclusions. Kinematic differences were found between the identified subpopulations in both breeds. The kinematic patterns of the subpopulations present in the ejaculate could influence fertility and reproductive performance.

The objective of this study was to evaluate how male age, semen extender, cooling (equilibration) time and freezing method influence the quality of Brahman bulls’ sperm after cryopreservation, as measured by Computer-Assisted Sperm Analysis (CASA) parameters. Six Brahman bulls, with an average age of 48.6±11.5 months, were used. Two ejaculates were collected for each animal on different days, with an interval of approximately one week between collections. Semen was diluted with three extenders: Andromed®, BioXcell®, and OptiXcell®. The samples [...] ABSTRACT The objective of this study was to evaluate how male age, semen extender, cooling (equilibration) time and freezing method influence the quality of Brahman bulls’ sperm after cryopreservation, as measured by Computer-Assisted Sperm Analysis (CASA) parameters. Six Brahman bulls, with an average age of 48.6±11.5 months, were used. Two ejaculates were collected for each animal on different days, with an interval of approximately one week between collections. Semen was diluted with three extenders: Andromed®, BioXcell®, and OptiXcell®. The samples