Lunar cycles at mating do not influence sex ratio at birth in horses.

The research article investigates whether lunar cycles at the time of horse mating impact the sex ratio of the offspring, concluding that there is no significant association between the two.

Objective of the Study

• The main goal of the study was to determine whether lunar phases have an influence on the sex ratio of horse offspring at birth. This question arose due to existing controversy regarding the influence of the moon on biological events, including animal and human birth. This research is particularly relevant for the horse industry, especially Polo Horse breeders, who tend to prefer female offspring.

Data Collected

• The data necessary for the research was provided by the Argentinean Stud Book, which maintains detailed records of horse matings. The study focused on the matings of Thoroughbred and Arab horses that took place between 2003 and 2011.

Analytical Approach

• The researchers investigated any statistical associations between mating dates at different lunar phases or days and the resulting sex ratio at birth. They assessed each lunar phase separately and counted the number of male and female offspring born from matings during these phases.

Results of the Study

• The study analyzed a total of 65,535 horse gestations. The resulting sex ratio at birth was 33,396 fillies (female foals) representing 50.96% of the total, and 32,139 colts (male foals) representing 49.04% of the total.
• Importantly, the researchers found that the percentages of males and females born after matings during different lunar phases or days were not statistically different. This means that the lunar phase during which mating took place did not significantly impact the sex of the offspring.

Conclusion of the Study

• The conclusion drawn from the study was that managing breeding dates in accordance with lunar cycles does not affect the sex ratio of offspring in horses. Breeds or breeders aiming to manipulate the sex ratio of their offspring cannot rely on lunar cycles to achieve this goal.