The Germplasm Bank of the Murciano Levantina (ML) bovine breed contains seven thousand, seven hundred and seventy‑five seminal doses, none of which have undergone sperm sexing treatment. The objective of this work is to know the influence of the ML bull on the seminal refreezing process. For this study, six ML bulls, declared threatened breed, were used as semen donors, where the seminal doses obtained were frozen and thawed using a conventional method; then refrozen and assessed by in vitro and in vivo fertility studies (artificial insemination-AI). The results obtained allow us to study fertility in vitro with results of seminal parameters considered sufficient. The results obtained after the AI of seven cows with refrozen semen from the bull that presented better fertility results in vitro was 71.43 % with pregnancy diagnosis at 45 days, and 57.14 % when the diagnosis was made at 60 days. The variability of the average values of the seminal parameters studied in vitro indicates significant differences (p < 0.05) among the six bulls in the study. The study of semen quality after refreezing, as well as the use of AI with refrozen semen could be used to determine the fertility of the bull, therefore, the seminal refreezing process could be used effectively for the conservation and recovery of threatened breeds such as ML.

Almela‑Veracruz L, Peinado‑Ramón B, Ruiz‑López S, Poto‑Remacha A (2022). Influencia del donante de semen en la recongelación de espermatozoides bovinos de raza Murciano Levantina. ITEA‑Información Técnica Económica Agraria 118(4): 580-593. https://doi.org/10.12706/itea.2022.002