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Cows Are More Likely to Give Birth During the Full Moon

Elizabeth Fox
3rd September, 2016

A team of researchers from the University of Tokyo has found that lunar cycles affect the timing of cow births. Spontaneous births in Holstein cows were more common on and around the full moon. The findings are in a paper just published in the journal PLOS ONE. Many people believe that lunar cycles affect the timing of births. Some even believe that this is the case for humans, though there hasn’t been any conclusive evidence. There have been anecdotal reports of cows giving birth during full moons but this phenomenon had not been previously studied. Researchers analyzed data from 428 Holstein cow births over a three year period. All of the births were spontaneous, not induced, and they were from cows on a private farm in Hokkaido, Japan. The research team compared the farm’s calving records to lunar cycles. The team found that there was a significant increase in births starting during the waxing gibbous moon phase. The number of births then peaked at the full moon before dropping back down. Cows that had already given birth before were much more likely to give birth during the full moon. The team found that cows were much more likely to give birth right before and during the full moon. This study is the first to show that lunar cycles influence the birth rates of cows. The researchers don’t currently have an explanation for why this happens and are planning further research. They hope to conduct a study with a larger sample size. It’s also unclear why this phenomenon was more common in cows that had previously given birth. Future research will focus on answering these questions while possibly applying the findings to human research. Cows are easy to study and may prove to be helpful models for studying the effect of moon phases on mammal births. REFERENCE Tomohiro Yonezawa, Mona Uchida, Michiko Tomioka, Naoaki Matsuki. Lunar Cycle Influences Spontaneous Delivery in Cows. PLOS ONE (2016).