Annual dynamics of semen-dose production in boars for commercial artificial insemination

Sevilla, Francisco; Araya-Zúñiga, Ignacio; Alvarado-Herrera, José Rafael; Molina-Montero, Rafael; Rodríguez, Julio; Vaquerano-Pineda, Felipe; Valverde, Anthony

doi:10.15517/n8n2pg88

Authors

Francisco Sevilla Instituto Tecnológico de Costa Rica, Campus Tecnológico Local San Carlos, Escuela de Agronomía, Centro de Investigación y Desarrollo en Agricultura Sostenible para el Trópico Húmedo (CIDASTH), Laboratorio de Reproducción Animal. Alajuela, Costa Rica. Author https://orcid.org/0000-0003-1480-4141
Ignacio Araya-Zúñiga Instituto Tecnológico de Costa Rica, Campus Tecnológico Local San Carlos, Escuela de Agronomía, Centro de Investigación y Desarrollo en Agricultura Sostenible para el Trópico Húmedo (CIDASTH), Laboratorio de Reproducción Animal. Alajuela, Costa Rica. Author https://orcid.org/0000-0002-4292-2287
José Rafael Alvarado-Herrera Instituto Tecnológico de Costa Rica, Campus Tecnológico Local San Carlos, Escuela de Agronomía, Centro de Investigación y Desarrollo en Agricultura Sostenible para el Trópico Húmedo (CIDASTH), Laboratorio de Reproducción Animal. Alajuela, Costa Rica. Author https://orcid.org/0009-0005-8171-6178
Rafael Molina-Montero Instituto Tecnológico de Costa Rica, Campus Tecnológico Local San Carlos, Escuela de Agronomía, Programa de Producción Agropecuaria (PPA). Alajuela, Costa Rica. Author https://orcid.org/0009-0009-3369-8058
Julio Rodríguez Instituto Tecnológico de Costa Rica, Campus Tecnológico Local San Carlos, Escuela de Agronomía, Programa de Producción Agropecuaria (PPA). Alajuela, Costa Rica. Author https://orcid.org/0000-0002-8426-8842
Felipe Vaquerano-Pineda Instituto Tecnológico de Costa Rica, Campus Tecnológico Central Cartago, Escuela de Agronegocios, Centro de Investigación en Gestión Agroindustrial (CIGA). Cartago, Costa Rica. Author https://orcid.org/0009-0008-5299-1463
Anthony Valverde Instituto Tecnológico de Costa Rica, Campus Tecnológico Local San Carlos, Escuela de Agronomía, Centro de Investigación y Desarrollo en Agricultura Sostenible para el Trópico Húmedo (CIDASTH), Laboratorio de Reproducción Animal. Alajuela, Costa Rica. Author https://orcid.org/0000-0002-3191-6965

DOI:

https://doi.org/10.15517/n8n2pg88

Keywords:

assisted reproduction, boar sperm, monthly dynamics, reproductive biotechnology, swine industry, thermal stress, tropical climate

Abstract

Introduction. Semen-dose production in boar artificial insemination (AI) centers depends on the temporal stability of ejaculate quality, yet monthly fluctuations remain insufficiently described under tropical commercial conditions. Objective. To characterize the monthly dynamics of semen-dose yield per ejaculate in boars managed under tropical commercial AI conditions and to identify the annual periods associated with reduced ejaculate productivity. Materials and methods. The study was conducted on commercial pig farms in northwestern Costa Rica between 2020 and 2024. A total of 461 ejaculates from 119 sexually mature boars were evaluated. Each ejaculate was macroscopically assessed to determine the number of semen doses that could be prepared. A dose from each ejaculate was transported to the laboratory at 17 °C. Total and progressive motility were evaluated using ISAS^® v1, and sperm morphology was assessed after sample fixation with the Trumorph^® system. Only ejaculates containing ≥75 % morphologically normal spermatozoa were analyzed. Monthly patterns were analyzed using mixed-effects models that included month, commercial breeding-purpose category, farm, year, and age at collection as fixed effects and boar as a random effect. Results. Sperm concentration, total and progressive motility, and semen-dose yield varied across months. Concentration peaked in March, declined to its lowest value in June, and gradually recovered, with a more pronounced increase in November. Total and progressive motility were relatively high in January, lower from February through June, and increased from July, peaking in August. Semen-dose yield remained below the overall mean from February through July and above it from August onward, despite a decline in October. Conclusions. Semen-dose yield per ejaculate in tropical boars followed a marked annual pattern. Identifying the low-output period may allow AI centers to anticipate adjustments in collection schedules, boar allocation, and semen-dose availability.

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References

Argenti, L. E., Parmeggiani, B. S., Leipnitz, G., Weber, A., Pereira, G. R., & Bustamante-Filho, I. C. (2018). Effects of season on boar semen parameters and antioxidant enzymes in the south subtropical region in Brazil. Andrologia, 50(4), Article e12951. DOI: https://doi.org/10.1111/and.12951

Boeters, M., Garcia-Morante, B., van Schaik, G., Segalés, J., Rushton, J., & Steeneveld, W. (2023). The economic impact of endemic respiratory disease in pigs and related interventions - a systematic review. Porcine Health Management, 9(1), Article 45. DOI: https://doi.org/10.1186/s40813-023-00342-w

Bronson, F. H. (2009). Climate change and seasonal reproduction in mammals. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1534), 3331–3340. DOI: https://doi.org/10.1098/rstb.2009.0140

Calderón-Calderón, J., Sevilla, F., Roldan, E. R. S., Barquero, V., & Valverde, A. (2022). Influence of fat-soluble vitamin intramuscular supplementation on kinematic and morphometric sperm parameters of boar ejaculates. Frontiers in Veterinary Science, 9, Article 908763. DOI: https://doi.org/10.3389/fvets.2022.908763

Dcunha, R., Hussein, R. S., Ananda, H., Kumari, S., Adiga, S. K., Kannan, N., Zhao, Y., & Kalthur, G. (2022). Current insights and latest updates in sperm motility and associated applications in assisted reproduction. Reproductive Sciences, 29, 7–25. DOI: https://doi.org/10.1007/s43032-020-00408-y

Dehghanbanadaki, H., Randell, Z., Cain, T., Fendereski, K., Horns, J. J., Ramsay, J. M., Gross, K. X., Pastuszak, A. W., & Hotaling, J. M. (2025). Seasonal variations in human semen parameters: a systematic review and meta-analysis. Andrology, 14(5), 1102–1120. DOI: https://doi.org/10.1111/andr.70167

Flowers, W. L. (2022). Factors affecting the production of quality ejaculates from boars. Animal Reproduction Science, 246, Article 106840. DOI: https://doi.org/10.1016/j.anireprosci.2021.106840

Fraser, L., Strzeżek, J., Filipowicz, K., Mogielnicka-Brzozowska, M., & Zasiadczyk, L. (2016). Age and seasonal-dependent variations in the biochemical composition of boar semen. Theriogenology, 86(3), 806–816. DOI: https://doi.org/10.1016/j.theriogenology.2016.02.035

Goldberg, A. M. G., Argenti, L. E., Faccin, J. E., Linck, L., Santi, M., Bernardi, M. L., Cardoso, M. R. I., Wentz, I., & Bortolozzo, F. P. (2013). Risk factors for bacterial contamination during boar semen collection. Research in Veterinary Science, 95(2), 362–367. DOI: https://doi.org/10.1016/j.rvsc.2013.06.022

Hancock, J. L., & Hovell, G. J. R. (1959). The collection of boar semen. Veterinary Record, 71, 664–665. https://www.cabidigitallibrary.org/doi/full/10.5555/19602201228

Harstine, B. R., Utt, M. D., & Dejarnette, J. M. (2018). Review: Integrating a semen quality control program and sire fertility at a large artificial insemination organization. Animal, 12(s1), s63–s74. DOI: https://doi.org/10.1017/S1751731118000319

Hensel, B., Henneberg, S., Kleve-Feld, M., Jung, M., & Schulze, M. (2024). Selection and direct biomarkers of reproductive capacity of breeding boars. Animal Reproduction Science, 269, Article 107490. DOI: https://doi.org/10.1016/j.anireprosci.2024.107490

Henneberg, S., Pieper, L., Selige, C., Jung, M., & Schulze, M. (2023). Analysis of artificial insemination center management factors that contribute to sperm parameters and boar longevity with a major focus on PGF2α treatment. Journal of Animal Science, 101, Article skad251. DOI: https://doi.org/10.1093/jas/skad251

Jongbo, A. O., de Borba, L. P., Pereira, R. M. M., Bello, Q. O., Gregoratto, L. L., de Souza, D. P., Adeyeye, O. A., & Vieira, F. M. C. (2026). Heat stress in livestock under tropical climates: impacts and mitigation strategies. Tropical Animal Health and Production, 58(2), Article 65. DOI: https://doi.org/10.1007/s11250-026-04848-7

Karageorgiou, M. A., Tsousis, G., Boscos, C. M., Tzika, E. D., Tassis, P. D., & Tsakmakidis, I. A. (2016). A comparative study of boar semen extenders with different proposed preservation times and their effect on semen quality and fertility. Acta Veterinaria Brno, 85(1), 023–031. DOI: https://doi.org/10.2754/avb201685010023

Knecht, D., Środoń, S., & Duziński, K. (2014). The influence of boar breed and season on semen parameters. South African Journal of Animal Science, 44(1), 1–9. DOI: https://doi.org/10.4314/sajas.v44i1.1

Kommisrud, E., Paulenz, H., Sehested, E., & Grevle, I. S. (2002). Influence of boar and semen parameters on motility and acrosome integrity in liquid boar semen stored for five days. Acta Veterinaria Scandinavica, 43(1), 49–55. DOI: https://doi.org/10.1186/1751-0147-43-49

Kondracki, S., & Górski, K. (2025). Analysis of factors of variation in characteristics of boar ejaculates. Animals, 15(14), Article 2043. DOI: https://doi.org/10.3390/ani15142043

Krupa, E., Krupová, Z., Žáková, E., Bauer, J., Moravčíková, N., & Vrtková, I. (2023). An assessment of the genetic parameters of boars’ reproductive traits. Genes, 14(11), Article 2003. DOI: https://doi.org/10.3390/genes14112003

Kunavongkrit, A., Suriyasomboon, A., Lundeheim, N., Heard, T. W., & Einarsson, S. (2005). Management and sperm production of boars under differing environmental conditions. Theriogenology, 63(2), 657–667. DOI: https://doi.org/10.1016/j.theriogenology.2004.09.039

Kuster, C. E., & Althouse, G. C. (2016). The impact of bacteriospermia on boar sperm storage and reproductive performance. Theriogenology, 85(1), 21–26. DOI: https://doi.org/10.1016/j.theriogenology.2015.09.049

León, J., Sevilla, F., Araya-Zúñiga, I., Silvestre, M. A., Barrientos, M., Molina-Montero, R., Roldan, E. R. S., & Valverde, A. (2025). Evaluating the effect of semen storage and dilution rate on boar sperm quality. Acta Agriculturae Scandinavica, Section A — Animal Science, 74(1), 59–71. DOI: https://doi.org/10.1080/09064702.2024.2430785

Li, J., Zhao, W., Zhu, J., Wang, S., Ju, H., Chen, S., Basioura, A., Ferreira-Dias, G., & Liu, Z. (2023). Temperature elevation during semen delivery deteriorates boar sperm quality by promoting apoptosis. Animals, 13(20), Article 3203. DOI: https://doi.org/10.3390/ani13203203

Lopez Rodriguez, A., Van Soom, A., Arsenakis, I., & Maes, D. (2017). Boar management and semen handling factors affect the quality of boar extended semen. Porcine Health Management, 3, Article 15. DOI: https://doi.org/10.1186/s40813-017-0062-5

Lucca, M. S., Gianluppi, R. D. F., Mellagi, A. P. G., Bortolozzo, F. P., Wentz, I., & Ulguim, R. da R. (2021). Effects of the classification of boars according to progressive sperm motility and the extender type on the reproductive performance of a single fixed-time insemination. Theriogenology, 161, 120–125. DOI: https://doi.org/10.1016/j.theriogenology.2020.11.018

Mellado, M., Sepulveda, E., Macias-Cruz, U., Avendaño, L., Garcia, J. E., Veliz, F. G., & Rodríguez, A. (2014). Effects of month of breeding on reproductive efficiency of Holstein cows and heifers inseminated with sex-sorted or conventional semen in a hot environment. Tropical Animal Health and Production, 46(1), 265–269. DOI: https://doi.org/10.1007/s11250-013-0470-8

Mengistu, D. A., Tezera, S. D., Birhanie, M. K., Kolech, T. A., Mekonen, A. W., Wassie, A. T., Endeshaw, A. G., Mekonnen, S. A., & Melsie, N. M. (2026). Assessment of artificial insemination practices, semen quality, and reproductive constraints in dairy farms in Central Gondar Zone, Ethiopia. BMC Veterinary Research, 22(1), Article 5. DOI: https://doi.org/10.1186/s12917-025-05161-5

Murphy, E. M., Kelly, A. K., O’Meara, C., Eivers, B., Lonergan, P., & Fair, S. (2018). Influence of bull age, ejaculate number, and season of collection on semen production and sperm motility parameters in Holstein Friesian bulls in a commercial artificial insemination centre. Journal of Animal Science, 96(6), 2408–2418. DOI: https://doi.org/10.1093/jas/sky130

National Research Council. (2012). Nutrient requirements of swine (11th rev. ed.). The National Academies Press.

Odinius, T. S., Siuda, M., Lautner, M., Leiding, C., Neuner, S., Bollwein, H., & Malama, E. (2024). Sperm functional status: a multiparametric assessment of the fertilizing potential of bovine sperm. Veterinary Sciences, 11(12), Article 678. DOI: https://doi.org/10.3390/vetsci11120678

Padilla, L., Lucas, X., Parrilla, I., Perez-Patiño, C., Rodriguez-Martinez, H., Roca, J., & Barranco, I. (2020). Period of boar ejaculate collection contributes to the yearly intra-male variability of seminal plasma cytokines. Biology, 9(5), Article 105. DOI: https://doi.org/10.3390/biology9050105

Pascal, C., Pânzaru, C., Radu-Rusu, R. M., Maciuc, V., Florea, A. M., & Nechifor, I. (2024). The influence of season and age on specific semen traits and reproductive behavior in Carpatina breed bucks. Agriculture, 14(11), Article 2092. DOI: https://doi.org/10.3390/agriculture14112092

Peña, S. T., Jr., Stone, F., Gummow, B., Parker, A. J., & Paris, D. B. B. P. (2019). Tropical summer induces DNA fragmentation in boar spermatozoa: implications for evaluating seasonal infertility. Reproduction, Fertility and Development, 31(3), 590–601. DOI: https://doi.org/10.1071/RD18159

Petrocelli, H., Batista, C., & Gosálvez, J. (2015). Seasonal variation in sperm characteristics of boars in southern Uruguay. Revista Brasileira de Zootecnia, 44(1), 1–7. DOI: https://doi.org/10.1590/S1806-92902015000100001

Quirino, M., Pereira, V. N., Tamanini, M. de S. C., Ulguim, R. da R., Schulze, M., Mellagi, A. P. G., & Bortolozzo, F. P. (2023). Sperm concentration of boar semen doses and sperm quality: novel perspectives based on the extender type and sperm resilience. Animal Reproduction Science, 255, Article 107293. DOI: https://doi.org/10.1016/j.anireprosci.2023.107293

Rocha, J. C., Rosa, E. R., Quirino, M., Marques, M. G., Bennemann, P. E., Coldebella, A., Rauber, L. P., Schwegler, E., Moreira, F., Peripolli, V., Lucia Junior, T., & Bianchi, I. (2024). Quality control of semen processing in boar studs: a Brazilian scenario. Scientia Agricola, 81, Article e20230164. DOI: https://doi.org/10.1590/1678-992x-2023-0164

Sá, P., Godinho, R. M., Gòdia, M., Sevillano, C. A., Harlizius, B., Madsen, O., & Bovenhuis, H. (2025). Genetic parameters and parental and early-life effects of boar semen traits. Genetics Selection Evolution, 57, Article 4. DOI: https://doi.org/10.1186/s12711-025-00954-6

Schulze, M., Henning, H., Rüdiger, K., Wallner, U., & Waberski, D. (2013). Temperature management during semen processing: impact on boar sperm quality under laboratory and field conditions. Theriogenology, 80(9), 990–998. DOI: https://doi.org/10.1016/j.theriogenology.2013.07.026

Schulze, M., Nitsche-Melkus, E., Jakop, U., Jung, M., & Waberski, D. (2019). New trends in production management in European pig AI centers. Theriogenology, 137, 88–92. DOI: https://doi.org/10.1016/j.theriogenology.2019.05.042

Schulze, M., Rüdiger, K., & Waberski, D. (2015). Rotation of boar semen doses during storage affects sperm quality. Reproduction in Domestic Animals, 50(4), 684–687. DOI: https://doi.org/10.1111/rda.12532

Sevilla, F., Araya-Zúñiga, I., Silvestre, M. Á., Cervantes-Acosta, P., Hernández-Beltrán, A., Salamanca-Carreño, A., & Valverde, A. (2026). Influence of age, breed lines and season on boar sperm motility and morphology under tropical conditions. Austral Journal of Veterinary Sciences, 58, Article e5802. DOI: https://doi.org/10.4206/ajvs.58.2

Sevilla, F., Murillo, L., Araya-Zúñiga, I., Silvestre, M. Á., Saborío-Montero, A., Vargas-Leitón, B., & Valverde, A. (2025). Effects of age, season, breed, and sperm counting chamber on boar semen quality variables in tropical conditions. Austral Journal of Veterinary Sciences, 57, Article e5701. DOI: https://doi.org/10.4206/ajvs.57.01

Sevilla, F., Soler, C., Araya-Zúñiga, I., Barquero, V., Roldan, E. R. S., & Valverde, A. (2023). Are there differences between methods used for the objective estimation of boar sperm concentration and motility? Animals, 13(10), Article 1622. DOI: https://doi.org/10.3390/ani13101622

Singh, M., Celina, A., Katiyar, R., Deori, S., Singh, A., Singh, V., Singh, G. D., Rajoriya, J. S., Kalita, H., & Mishra, V. K. (2025). Alteration in sperm mitochondrial membrane potential and antioxidant biomarkers in summer adversely affects Hampshire-Ghungroo crossbred boar semen fertility in sub-tropical climate. Frontiers in Veterinary Science, 12, Article 1562988. DOI: https://doi.org/10.3389/fvets.2025.1562988

Sui, H., Wang, S., Liu, G., Meng, F., Cao, Z., & Zhang, Y. (2022). Effects of heat stress on motion characteristics and metabolomic profiles of boar spermatozoa. Genes, 13(9), Article 1647. DOI: https://doi.org/10.3390/genes13091647

Suliman, Y., Becker, F., Tuchscherer, A., & Wimmers, K. (2020). Seasonal variations in quantitative and qualitative sperm characteristics in fertile and subfertile stallions. Archives Animal Breeding, 63(1), 145–154. DOI: https://doi.org/10.5194/aab-63-145-2020

Suriyasomboon, A., Lundeheim, N., Kunavongkrit, A., & Einarsson, S. (2004). Effect of temperature and humidity on sperm production in Duroc boars under different housing systems in Thailand. Livestock Production Science, 89(1), 19–31. DOI: https://doi.org/10.1016/j.livprodsci.2003.12.008

Toledo-Guardiola, S. M., Luongo, C., Martínez-Pastor, F., Soriano-Úbeda, C., & Matás, C. (2025). The individual variations in sperm quality of high-fertility boars impact the offspring production and early physiological functions. Veterinary Sciences, 12(6), Article 582. DOI: https://doi.org/10.3390/vetsci12060582

Tsakmakidis, I. A., Lymberopoulos, A. G., & Khalifa, T. A. A. (2010). Relationship between sperm quality traits and field-fertility of porcine semen. Journal of Veterinary Science, 11(2), 151–154. DOI: https://doi.org/10.4142/jvs.2010.11.2.151

Valverde, A., Barquero, V., & Carvajal, V. (2021). Applied biotechnology to the study of the boar semen motility. Agronomía Mesoamericana, 32(2), 662–680. DOI: https://doi.org/10.15517/am.v32i2.40628

Waberski, D., Petrunkina, A. M., & Töpfer-Petersen, E. (2008). Can external quality control improve pig AI efficiency? Theriogenology, 70(8), 1346–1351. DOI: https://doi.org/10.1016/j.theriogenology.2008.06.006

Waberski, D., Riesenbeck, A., Schulze, M., Weitze, K. F., & Johnson, L. (2019). Application of preserved boar semen for artificial insemination: Past, present and future challenges. Theriogenology, 137, 2–7. DOI: https://doi.org/10.1016/j.theriogenology.2019.05.030

Walter, M. P., Bottan, J., Machado, S. A., Bennemann, P. E., & Bragança, J. F. M. (2020). Characterization of boar studs in Brazil. Ciência Rural, 50(11), Article e20190998. DOI: https://doi.org/10.1590/0103-8478cr20190998

Žaja, I. Ž., Samardžija, M., Vince, S., Majić-Balić, I., Vilić, M., Duričić, D., & Milinković-Tur, S. (2016). Influence of boar breeds or hybrid genetic composition on semen quality and seminal plasma biochemical variables. Animal Reproduction Science, 164, 169–176. DOI: https://doi.org/10.1016/j.anireprosci.2015.11.027

Zak, L. J., Gaustad, A. H., Bolarin, A., Broekhuijse, M. L. W. J., Walling, G. A., & Knol, E. F. (2017). Genetic control of complex traits, with a focus on reproduction in pigs. Molecular Reproduction and Development, 84(9), 1004–1011. DOI: https://doi.org/10.1002/mrd.22875

Zasiadczyk, L., Fraser, L., Kordan, W., & Wasilewska, K. (2015). Individual and seasonal variations in the quality of fractionated boar ejaculates. Theriogenology, 83(8), 1287–1303. DOI: https://doi.org/10.1016/j.theriogenology.2015.01.015