De la Torre, JavierSánchez Martín, PascualGosálvez Berenguer, JaimeCrespo Castejón, Francisco2024-01-312024-01-312017de la Torre J, Sánchez-Martín P, Gosálvez J, Crespo F. Equivalent seminal characteristics in human and stallion at first and second ejaculated fractions. Andrologia. 2017 Oct;49(8)0303-456910.1111/and.12708https://hdl.handle.net/20.500.14352/97392Sperm quality was assessed in normozoospermic human (n = 10) and Spanish breed stallion (n = 10) after sperm fractionation during ejaculation. The first ejaculated frac-tion was separated from the second. A third sample was reconstituted using equiva-lent proportion of both fractions (RAW). Fraction 1, Fraction 2 and RAW semen were incubated for 30 min at 37°C to homogenise the impact of iatrogenic damage be-tween both species. Sperm concentration, motility and sperm DNA damage were as-sessed in each fraction and RAW semen. The results showed two important facts: (i) spermatozoa confined at Fraction 1 exhibit superior parameters than those included at Fraction 2 in both species, and (ii) there is a certain level of concordance between spe-cies in the proportion of benefit observed when Fraction 1 is compared to RAW semen. Altogether, these results call into question whether the standard practice of whole ejaculate collection can be considered the best strategy when using male gam-etes for artificial insemination. In fact, the reconstituted RAW semen exhibits poorer semen characteristics than those found in Fraction 1.engjournal articlehttps://doi.org/10.1111/and.1270827660115https://pubmed.ncbi.nlm.nih.gov/27660115/restricted access61Ejaculate fractionationEquus caballusHomo sapiensSCDSperm DNA fragmentationVeterinaria24 Ciencias de la Vida