The influence of artificial light to the prepartum mare on hair growth of the developing foetus in utero

Abstract

The objective of this study was to determine if photoperiodic stimulus to a pre-partum mare would affect hair growth in the developing foetus. In seasonal breeders, time of year photoperiodic information is thought to be conveyed to the system through the presence or absence of melatonin. Through the use of artificial light we were able to expose pregnant mares to an extended photoperiod nearing the end of gestation. Through collection of hair samples from newborn foals and recording both hair weight and length we were able to detect significant differences between both hair length and weight between treatment and control groups. The results of this experiment suggest that the developing fetus is sensitive to changes in hormonal secretions in the mare and uses information regarding the prevailing environmental light/dark cycle to prepare for ex utero living conditions.