By The Light Of The Moon: Do Lunar Phases Affect Foal Gender? – Horse Racing News

By The Light Of The Moon: Do Lunar Phases Affect Foal Gender? – Horse Racing News

If an old wives’ tale is to be believed, the phase of the moon when a mare is bred may influence her foal’s gender. 

Scientists at the Universidad Nacional de Río Cuarto in Argentina reviewed 65,535 gestations recorded in the Argentinean Stud Book, which includes every breeding of registered Arabian and Thoroughbred horses from 2003 to 2011. They compared this information to the lunar phase at the time of the breeding, and the gender of the resulting foal. 

In total, 51 percent of the foals were fillies and 49 percent were colts. This ratio stayed statistically consistent no matter what phase the moon was in when the mares were bred. 

The researchers conclude that managing the breeding dates of mares in relation to lunar phase to try to manipulate the sex of the offspring is not viable.

Read more at EQUUS magazine. 

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