Contreras Huamani, MijailGuillen Palomino, Crissthel YverlinOrellana Berrocal, Harumi RebecaLaines Arcce, Irwin MitchellBellido Quispe, Dionet KenyAcuña Leiva, Alex YonySilva Chaves, Maianade Figueirêdo Freitas, Vicente José2025-06-022025-06-022025-05-22Contreras, M; Guillen,C.; Orellana, H.; Laines, I.; Bellido, D.; Acuña, A-; Silva, M.; de Figueirêdo, V. Influence of reproductive season and testicular volume on seminal parameters of alpacas (Vicugna pacos). Trop Anim Health Prod 57, 227 (2025). https://doi.org/10.1007/s11250-025-04478-51573-7438http://hdl.handle.net/20.500.12955/2760The male alpaca plays an important role in the reproductive process and, consequently, in genetic improvement. South American camelids (SACs) have a well-defined reproductive season, particularly in the Andean region. The objective was to evaluate the influence of reproductive and non-reproductive seasons, as well as testicular volume, on seminal parameters in alpacas. Nine healthy male alpacas, over 4 years old, were selected for this experiment. Semen samples were taken every two days using an artificial vagina incorporated into a dummy. The collected were in the reproductive (November to April) and non-reproductive (May to October) seasons, from breeders with testicular volumes that range between 63–70 cm3 and 83–94 cm3. The total number of ejaculates collected was 72 per season, with 8 samples collected from each male. Macroscopic aspects such as color, volume (ml), thread formation (cm) and foam (cm) were evaluated, in addition to microscopic aspects such as sperm motility (%), viability (%) concentration (sperm/ml) and total number of sperm. The results were analyzed with the Mann–Whitney non-parametric test, using the R 3.4.3 software, considering P < 0.05 as the significance level. A decrease in thread formation was observed in semen collected during the reproductive season compared to the non-reproductive season (P < 0.05). On the other hand, sperm motility and viability in semen collected during the reproductive period was higher (p < 0.05). Regarding testicular volume, alpacas with larger testicular volume had greater ejaculate volume, sperm concentration and total number of sperm (p < 0.05). Based on these results, it is possible to conclude that the semen of alpaca breeders is influenced by the season, and that testicular volume can predict their reproductive capacity, being a parameter to be considered when selecting the best breeding male.application/pdfenginfo:eu-repo/semantics/restrictedAccessAlpacaTesticular volumenReproductive seasonSeminal parametersinfo:eu-repo/semantics/articlehttps://purl.org/pe-repo/ocde/ford#4.00.00https://doi.org/10.1007/s11250-025-04478-5Alpacas; reproductive physiology; semen quality; animal reproduction; seasonal variation