Effect of increased daylight during late pregnancy on the reproductive performance of mares after parturition.

The research paper is about the effect of prolonged daylight exposure on the reproductive performance of pregnant mares, showing that mares exposed to prolonged photoperiod had a slightly enhanced fertility cycle post-parturition.

Objective of the Study

• The study aimed to measure the impact of extended light exposure in a day, specially during the last couple of months of pregnancy, on the ovarian activity and fertility in mares post-childbirth.

Methodology of the Study

• 13 pregnant mares due to give birth in January and February were exposed to an extended photoperiod (16 hours of light and 8 hours of darkness) from November 15 until one month post-childbirth.
• As a comparison, a control group of 9 mares due to give birth at the same time were kept under the natural light conditions. Both groups were managed with the same regimen and within the same stable.

Results of the Study

• The research found that light-treated mares experienced ovulation approximately 3 days earlier during their foal oestrus than the control mares, a difference that was statistically significant.
• The percentages of mares that did not show ovarian activity during winter were 7.6% in the light-treated group and 33% in the control group.
• Other processes like uterine involution and expulsion of uterine fluid were observed to be similar in both treated and control groups.
• The final pregnancy rates were high in both groups, with 92% in the light-treated group and 89% in the control group.
• The time period from childbirth to next pregnancy, called the ‘open period’, was significantly shorter in the light-treated mares compared to the untreated control mares.

Conclusion

• The exposure to an extended photoperiod during the final stages of pregnancy in mares resulted in an earlier onset of ovulation and a shorter ‘open period’ post-parturition than mares under normal lighting conditions. This slight enhancement in the fertility cycle could have potential implications for horse breeding practices in future.