Assessment of the sexual behavior of pregnant mares.

The research focuses on the sexual behavior of pregnant horses (mares) in the presence of male horses (stallions), noting that these mares do not exhibit sexual activity during pregnancy, even when their hormone levels change.

Study Methodology

• The study involved twelve pregnant mares who were observed from the beginning of their gestation period until childbirth.
• The mares were placed with a stallion and observed for 20 minutes every day for five days each month. This observation period ran from September to July.
• The research aimed to examine any changes in sexual behavior or social interaction between the mares and the stallion or between mares, with different months and gestation stages.

Study Findings

• Throughout the study, the mares did not show any signs of estrus, a period of sexual receptivity in female mammals, and there were no instances of copulation.
• Social interactions, such as male approaches and mutual grooming between females, were seen more frequently during the spring and fall months than in winter months. These social behaviors were not dependent on the gestation month.
• Similar behavior was noted in non-pregnant mares in their diestrous phase (a period when sexual activity is suppressed). In these cases as well, there was no sexual behavior and no differences in social interactions.

Interpretation of Results

• The results indicate that pregnant mares do not exhibit sexual activity during their term, despite fluctuations in hormonal levels. This was observed even during times of high estrogen and low progesterone levels, when sexual activity might be more likely.
• Progesterone, a hormone that inhibits sexual activity, seems to be responsible for the lack of sexual behavior in diestrous mares. However, the researchers suggest that another unidentified substance that suppresses sexual behavior may be present during pregnancy.