Semen quality on ram: a review
DOI:
https://doi.org/10.29059/cvpa.v4i1.50Keywords:
semen quality, ram, cryopreservation, heat stress, sheepAbstract
Sperm quality is an essential component of reproductive efficiency in sheep and constitutes a key parameter in the application of biotechnologies such as artificial insemination and cryopreservation. Sperm volume, concentration, motility, morphology, and viability are seminal parameters that are affected by heat stress, nutrition, and reproductive management. Excessive heat causes a decrease in spermatogenesis, reduced sperm motility and concentration, and an increase in morphological abnormalities accompanied by cell death. Intense cold causes structural damage and loss of viability due to intracellular crystallization. Additionally, factors such as age, breed, and nutrition modulate semen quality, with antioxidants acting as protective elements against oxidative stress. Cryopreservation is limited by the low tolerance of sperm to cold, the toxicity of some cryoprotectants and underlying pathologies of the reproductive system. Understanding these, environmental, physiological, and pathological factors allow the establishment of management and conservation strategies to optimize fertility in sheep.
References
Abecia, J. A., Forcada, F., & González-Bulnes, A. (2012). Hormonal control of reproduction in small ruminants. Animal Reproduction Science, 130(3-4), 173-179. https://doi.org/10.1016/j.anireprosci.2012.01.011
Abril-Sánchez, S., Freitas-de-Melo, A., Giriboni, J., Santiago-Moreno, J., & Ungerfeld, R. (2019). Sperm collection by electroejaculation in small ruminants: A review on welfare problems and alternative techniques. Animal Reproduction Science, 205, 1-9. https://doi.org/10.1016/j.anireprosci.2019.03.023
Ahmadi, E., Tahmasebian-Ghahfarokhi, N., Nafar-Sefiddashti, M., Sadeghi-Sefiddashti, M., & Hassanpour, H. (2020). Impacts of in vitro thermal stress on ovine epididymal spermatozoa and the protective effect of β-mercaptoethanol as an antioxidant. Veterinary Research Forum, 11(1), 43-51. https://doi.org/10.30466/vrf.2018.83527.2096
Aitken, R. J. (2006). Sperm function tests and fertility. International Journal of Andrology, 29(1), 69-75. https://doi.org/10.1111/j.1365-2605.2005.00630.x
Al-Katib, W., & Dennis, S. (2009). Ovine genital actinobacillosis: A review. New Zealand Veterinary Journal, 57(6), 352-358. https://doi.org/10.1080/00480169.2009.64722
Arrebola, F., Castillejo‐Lacalle, E., Borjas‐Muñoz, F., Querino‐Santiago, F. J., Redondo‐Cardador, F. C., & Abecia, J. (2022). Comparison of four strategies of ram management in a semen collection centre. Reproduction in Domestic Animals, 57(S5), 103-105. https://doi.org/10.1111/rda.14120
Barragán Sierra, A., Avendaño-Reyes, L., Hernández Rivera, J. A., Vicente-Pérez, R., Correa-Calderón, A., Mellado, M., Meza-Herrera, C. A., & Macías-Cruz, U. (2021). Termorregulación y respuestas reproductivas de carneros bajo estrés por calor. Revisión. Revista Mexicana de Ciencias Pecuarias, 12(3), 910-931. https://doi.org/10.22319/rmcp.v12i3.5624
Bartlewski, P. M., Baby, T. E., & Giffin, J. L. (2011). Reproductive cycles in sheep. Animal Reproduction Science, 124(3-4), 259-268. https://doi.org/10.1016/j.anireprosci.2011.02.024
Carlos, J., Parra, L., Moyano, J. C., Marini, P. R., & Fischman, M. L. (2019). Variación de la calidad seminal frente a una infección bacteriana sistémica en carneros Blackbelly. Revista de Producción Animal, 31(3). https://rpa.reduc.edu.cu/index.php/rpa/article/view/92
Carrascal-Triana, E. L., Moya Romero, D. C., Herrera Perez, N., & Cañas Alvarez, J. J. (2022). Características seminales de ovinos bajo condiciones ambientales del Caribe Colombiano. Revista de Investigaciones Veterinarias del Perú, 33(4), e21611. https://doi.org/10.15381/rivep.v33i4.21611
Cognie, Y. (1999). State of the art in sheep-goat embryo transfer. Theriogenology, 51(1), 105-116. https://doi.org/10.1016/S0093-691X(98)00235-0
Cruz-Espinoza, F., Gallegos-Sánchez, J., Mendieta-Galán, T. A., Hernández, C. I. M., & Salazar-Ortiz, J. (2021). Reproductive management of the ram (Ovis orientalis aries). Agro Productividad, 5. https://doi.org/10.32854/agrop.v14i8.2101
David, I., Robert-Granié, C., Manfredi, E., Lagriffoul, G., & Bodin, L. (2008). Environmental and genetic variation factors of artificial insemination success in French dairy sheep. Animal, 2(7), 979-986. https://doi.org/10.1017/S1751731108002152
Dovenski, T., Trojacanec, P., Atanasov, B., Nikolovski, M., Petkov, V., Popovska-Percinic, F., Dovenska, M., Grizelj, J., & Vince, S. (2022). Novelties in ovine assisted reproductive technologies–a review. Macedonian Veterinary Review, 45(2), 109-125. https://doi.org/10.2478/macvetrev-2022-0018
Griswold, M. D. (2015). Spermatogenesis: The commitment to meiosis. Physiological Reviews, 96(1), 1-17. https://doi.org/10.1152/physrev.00013.2015
Guo, X., Xu, J., Zhao, Y., Wang, J., Fu, T., Richard, M. L., Sokol, H., Wang, M., Li, Y., Liu, Y., Wang, H., Wang, C., Wang, X., He, H., Wang, Y., Ma, B., & Peng, S. (2024). Melatonin alleviates heat stress-induced spermatogenesis dysfunction in male dairy goats by regulating arachidonic acid metabolism mediated by remodeling the gut microbiota. Microbiome, 12(1), 233. https://doi.org/10.1186/s40168-024-01942-6
Holt, W. V, & Van Look, K. J. W. (2004). Concepts in sperm heterogeneity, sperm selection and sperm competition as biological foundations for laboratory tests of semen quality. Reproduction, 127(5), 527-535. https://doi.org/10.1530/rep.1.00134
Huang, Z., Gao, L., Hou, Y., Zhu, S., & Fu, X. (2019). Cryopreservation of farm animal gametes and embryos: recent updates and progress. Frontiers of Agricultural Science and Engineering, 6(1), 42. https://doi.org/10.15302/J-FASE-2018231
Jiménez-Rabadán, P., Soler, A. J., Ramón, M., García-Álvarez, O., Maroto-Morales, A., Iniesta-Cuerda, M., Fernández-Santos, M. R., Montoro, V., Pérez-Guzmán, M. D., & Garde, J. J. (2016). Influence of semen collection method on sperm cryoresistance in small ruminants. Animal Reproduction Science, 167, 103-108. https://doi.org/10.1016/j.anireprosci.2016.02.013
Luis, R. G., Rocío, S. M., & Alexei, S. A. (2015). Evaluation of ram sperm quality post-thawing by using two energy sources and two cryoprotectants. Revista de Investigaciones Veterinarias del Perú, 26(1), 49-56. https://doi.org/10.15381/rivep.v26i1.10942
Luo, J., Wang, W., & Sun, S. (2019). Research advances in reproduction for dairy goats. Asian-Australasian Journal of Animal Sciences, 32(8), 1284-1295. https://doi.org/10.5713/ajas.19.0486
Marai, M., El-Darawany, I. F. M., Fadiel, A. A. & Abdel-Hafez, M. A. M. (2008). Reproductive performance traits as affected by heat stress and its alleviation in sheep. Tropical and Subtropical Agroecosystems, 8(3), 209-234. http://www.redalyc.org/articulo.oa?id=93911235001
Moradi, M., Karimi, I., Ahmadi, S., & Mohammed, L. J. (2020). The necessity of antioxidant inclusion in caprine and ovine semen extenders: A systematic review complemented with computational insight. Reproduction in Domestic Animals, 55(9), 1027-1043. https://doi.org/10.1111/rda.13754
Moustacas, V. S., Silva, T. M. A., Costa, L. F., Carvalho Júnior, C. A., Santos, R. L., & Paixão, T. A. (2014). Clinical and pathological changes in rams experimentally infected with Actinobacillus seminis and Histophilus somni. The Scientific World Journal, 2014, 241452. https://doi.org/10.1155/2014/241452
Olsen, S. C., & Palmer, M. V. (2014). Advancement of knowledge of Brucella over the past 50 years. Veterinary Pathology, 51(6), 1076-1089. https://doi.org/10.1177/0300985814540545
Poester, F., Samartino, L., & Santos, R. (2013). Pathogenesis and pathobiology of brucellosis in livestock. Revue Scientifique Et Technique de L OIE, 32(1), 105-115. https://doi.org/10.20506/rst.32.1.2193
Rizkallah, N., Chambers, C. G., de Graaf, S. P., & Rickard, J. P. (2022). Factors affecting the survival of ram spermatozoa during liquid storage and options for improvement. Animals, 12(3), 244. https://doi.org/10.3390/ani12030244
Ruiz, G. L., Sandoval, M. R., & Santiani, A. A. (2015). Evaluación de la calidad espermática del semen ovino posdescongelación al emplear dos fuentes energéticas y dos crioprotectores. Revista de Investigaciones Veterinarias del Perú, 26(1), 49. https://doi.org/10.15381/rivep.v26i1.10942
Sabeti, P., Pourmasumi, S., Rahiminia, T., Akyash, F., & Talebi, A. R. (2016). Etiologies of sperm oxidative stress. International Journal of Reproductive Biomedicine, 14(4), 231-240.
Sadeghi, S., Del Gallego, R., García-Colomer, B., Gómez, E. A., Yániz, J. L., Gosálvez, J., López-Fernández, C., & Silvestre, M. A. (2020a). Effect of sperm concentration and storage temperature on goat spermatozoa during liquid storage. Biology, 9(9), 300. https://doi.org/10.3390/biology9090300
Sadeghi, S., Del Gallego, R., García-Colomer, B., Gómez, E. A., Yániz, J. L., Gosálvez, J., López-Fernández, C., & Silvestre, M. A. (2020b). Effect of sperm concentration and storage temperature on goat spermatozoa during liquid storage. Biology, 9(9), 300. https://doi.org/10.3390/biology9090300
Saha, A., Asaduzzaman, M., & Bari, F. Y. (2022). Cryopreservation techniques for ram sperm. Veterinary Medicine International, 2022, 7378379. https://doi.org/10.1155/2022/7378379
Tsakmakidis, I. A. (2010). Ram semen evaluation: Development and efficiency of modern techniques. Small Ruminant Research, 92(1-3), 126-130. https://doi.org/10.1016/j.smallrumres.2010.04.017
Van de Hoek, M., Rickard, J. P., & De Graaf, S. P. (2022). Motility assessment of ram spermatozoa. Biology, 11(12), 1715. https://doi.org/10.3390/biology11121715
van Wettere, W. H. E. J., Kind, K. L., Gatford, K. L., Swinbourne, A. M., Leu, S. T., Hayman, P. T., Kelly, J. M., Weaver, A. C., Kleemann, D. O., & Walker, S. K. (2021). Review of the impact of heat stress on reproductive performance of sheep. Journal of Animal Science and Biotechnology, 12(1), 26. https://doi.org/10.1186/s40104-020-00537-z
Wang, Q.-J., Yi, H.-M., Ou, J.-Y., Wang, R., Wang, M.-M., Wang, P.-H., He, X.-L., Tang, W.-H., Chen, J.-H., Yu, Y., Zhang, C.-P., Ren, C.-H., & Zhang, Z.-J. (2024). Environmental heat stress decreases sperm motility by disrupting the diurnal rhythms of rumen microbes and metabolites in Hu rams. International Journal of Molecular Sciences, 25(20), 11161. https://doi.org/10.3390/ijms252011161
Wang, Y., Fu, X., & Li, H. (2025). Mechanisms of oxidative stress-induced sperm dysfunction. Frontiers in Endocrinology, 16, 1520835. https://doi.org/10.3389/fendo.2025.1520835
Wickramasingha, D., Schumann, F., Sayi, S., Toews, A., Gabadage, K., Fernandopulle, R., & Dadarwal, D. (2025). Semen quality and pathological lesions in rams naturally infected with Brucella ovis during an outbreak in Saskatchewan. The Canadian Veterinary Journal = La Revue Veterinaire Canadienne, 66(5), 523-532.
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Ciencias Veterinarias y Producción Animal

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Accepted 2026-07-13
Published 2026-07-15






