Fases lunares y su relación con el sexo del ternero en diferentes razas productoras de carne

The objective of this work was to analyze the relationship of the lunar phases in beef cattle calving, as well as the influence of the lunar phase of insemination on the sex of the offspring, during the period 1994-2020. The breeds used were Hereford and Angus, and their respective crosses. The database of the breeding herd of the Bernardo Rosengurtt Experimental Station of the Faculty of Agronomy, located in the department of Cerro Largo, Uruguay, was used. It has a total of 4961 data, registering 3765 births. The lunar phases used were: waxing, waxing fourth, waning, and waning fourth, new and full. It was observed that there is an influence of the insemination moon on the sex of the calves, where it was found that the number of males is greater when the cows are inseminated in the lunar phase of the crescent and new moon. But no influence of the birth moon on sex was found. In relation to births, the highest number occurred in the waxing phase with respect to the waning phase, and within the phases of one day's duration, births were predominant in the new moon, with lower values in the full moon. The distribution of births in the different moons varies with the genotypes of the cows.