130 Moon cycle influences pregnancy rate and pregnancy losses following transfer of bovine embryos produced in vitro

F. P. Perea; H. J. Hernandez-Fonseca; A. M. Cambraia Esteves; J. L. Lobo Alves Correia; A. C. Nogueira; P. C. Villamediana-Monreal

doi:10.1071/RDv36n2Ab130

RESEARCH ARTICLE

130 Moon cycle influences pregnancy rate and pregnancy losses following transfer of bovine embryos produced in vitro

F. P. Perea ^A , H. J. Hernandez-Fonseca ^B , A. M. Cambraia Esteves ^C , J. L. Lobo Alves Correia ^C , A. C. Nogueira ^D and P. C. Villamediana-Monreal ^E

+ Author Affiliations

- Author Affiliations

^A Facultad de Ciencias Agropecuarias, Universidad de Cuenca, Cuenca. Ecuador

^B Department of Anatomy, Physiology and Pharmacology, School of Veterinary Medicine, St. George’s University, St. George, Grenada, West Indies

^C BH Embriões, Belo Horizonte, MG, Brazil

^D Apoyar Biotech LTD, Lagoa Santa, MG, Brazil

^E Department of Dairy and Food Science, South Dakota State University, Brookings, SD, USA

Reproduction, Fertility and Development 36(2) 218 https://doi.org/10.1071/RDv36n2Ab130

The influence of the lunar cycle (LC) on the reproductive activity in farm animals has been demonstrated. However, little is known about the effect of the LC on the pregnancy rate of in vitro embryo recipient cows. This retrospective study (2020–2022) aimed to assess the influence of the lunar cycle on PR after transfer of in vitro-produced embryos (n = 12445). Oocytes were collected from Gyr donors in 54 farms (Minas Gerais, Brazil). In vitro Gyr × Holstein embryos were produced in a commercial laboratory, following protocols for such purposes. Only fresh 7-day expanded blastocysts were transferred. All recipients were synchronized with an 8-day oestradiol/progesterone-based protocol. Pregnancy was diagnosed by ultrasound at 30 and 60 days post-transfer. According to the percentage of moonlight, the LC was divided into 30 periods of 0.98 days each (periods 1–15 crescent phase; periods 16–30 waning phase). The number of embryo transfers throughout the LC ranged between 171 and 1266 (415 ± 275 transfers). Data were analysed by logistic regression of SAS (month, year, farm, and technician were also considered as independent variables). Pregnancy rates (PR) at 30 (43.0 vs 40.4%) and 60 days (38.9 vs 36.6%) were greater in the waning (from full to new moon) than in the crescent (from new to full moon) phase of the LC (P < 0.01). The PR was influenced by the LC both at the day the transfer was performed (P < 0.0001) and at the day the oocytes were collected (P < 0.0001). In both cases, PR at 30 and 60 days followed a similar pattern across the LC. For purposes of this report, only the effect of the LC at the time of transfer will be described. The effect of the LC on the day of transfer resulted in PR (at 30 days) ranging from 28.9 (period 6; 50/173) to 58.2% (period 29; 152/366). The highest PR occurred in periods 20 to 27 (48.5%) compared to the remaining periods of the LC (40.3%; P < 0.0001). The same pattern was observed for PR at 60 days. Pregnancy losses showed large variability throughout the lunar cycle, ranging from 0.6 (period 9) to 7.5% (period 21), however, the average between the crescent (3.9%) and waning (4.3%) phases did not differ. In conclusion, the LC influenced the PR following the transfer of fresh in vitro-produced embryos. Periods 20 to 27 were the most fertile of the LC and, therefore, the most convenient for transfers of in vitro-produced embryos.