Relation between leptin and estradiol levels in Egyptian lactating Arab mares during foaling heat.

The research examines the relationship between the hormones leptin and estradiol in lactating Arab mares during their first postpartum estrus (or heat) after foaling (giving birth). The study finds a significant positive correlation between these hormone levels, suggesting that leptin plays an important role in the ovulation cycle in postpartum mares.

Research Methodology

• The research was carried out on 16 Arab lactating mares from Al-Zahraa Arab Horse Stud.
• Each mare underwent two ultrasound examinations with a three-week interval, starting from the day they demonstrated foaling heat.
• The team collected daily blood samples from the birth of the foal until the first postpartum estrus, typically around day 11.
• Observations of estrous signs were also carried out daily.

Hormonal Analysis and Findings

• The researchers tracked levels of both leptin and estradiol hormones in the mares.
• On average, the mares experienced foaling heat around 8.9 days after giving birth.
• Mares that went into estrus on days 9 and 10 had a higher conception rate than those entering earlier or later.
• Estradiol hormone levels were found to be high after foaling and then decreased after the expression of foaling heat.
• Conversely, leptin levels rose from day 8 to day 10 compared to other days before and after the first ovulation.

Correlation Between Leptin and Estradiol

• A significant positive correlation was discovered between levels of estradiol and leptin, marked by a correlation coefficient (r) of 0.58.
• This positive correlation suggests that the leptin hormone plays a key role in ovulation during the first postpartum estrus in mares.

Implications and Conclusions

• The study’s findings contribute to the understanding of hormone interactions during reproduction in mares, specifically in the postpartum period.
• Understanding the role of leptin in ovulation during the first postpartum estrus could potentially help in better managing reproduction in horses and possibly in other animals as well.