1Autonomous Agrarian University Antonio Narro, Laguna Unit, Torreon, Coahuila, Mexico
2Autonomous Agrarian University Antonio Narro, Saltillo Unit, Saltillo, Coahuila, Mexico
3Technical University of Manabí, Ecuador
4Private Practice, Gibraltar Farm, DurangoMéxico
*Corresponding Author: J.L. Morales, Autonomous Agrarian University Antonio Narro, Laguna Unit, Torreon, Coahuila, Mexico, Email: moralesnarrojlm@gmail.com
Season of the year can affect the reproductive behavior in Holstein cows, altering the competition of the oocytes, reflecting a reduced production of embryos. The objective of this study was to evaluate the average of total oocytes, competition of oocytes and embryos in the in vitro production process at different season of the year in Holstein cows.
During the four seasons of the year, was performed on each of the oocyte donor cows (winter, n = 957; spring, n = 1571; summer, n = 1776; autumn, n = 1128), by in vivo transvaginal follicular aspiration technique after the collection were subjected to the embryos production in vitro.
The highest number of total embryos were produced in winter and autumn, compared to spring and summer (3.76±0.16 and 3.54±0.18 vs. 2.73±0.11 and 2.45±0.10; respectively, P<0.05). During winter, a higher percentage of oocyte competition was observed, followed by autumn and spring and less competition shown in summer (26.03±0.39, 19.08±0.29, respectively, P<0.05). The quantity and competence of the oocytes collected and in vitro embryo production were drastically reduced during the hottest months of the year in this area of intense heat.
Competence of oocytes, Embryos, Holstein, In vitro fertilization, Season
