Clinical findings, pathological changes and endocrinological secretory patterns in mares with ovarian tumours.

This research aims to analyze the clinical, structural, and functional aspects of ovarian tumors in 10 mares, focusing on the observed changes in their endocrinological secretory patterns and linking these changes with the pathological and behavioral outcomes detected in the animals.

Study Participants and Primary Observations

• The study was conducted on 10 mares that were found to have ovarian tumors.
• On a microscopic level, proliferation of certain types of cells, specifically granulosa cells within large and small follicles, along with the presence of diverse quantities of Leydig-like cells within the theca interna, was the principal observation noted in 9 out of the 10 mares.

Testosterone Levels and Behavior

• All 9 of these mares were found to have a higher than normal concentration of testosterone in their peripheral plasma, which was statistically significant (P less than 0.005).
• Interestingly, the two mares showcasing male behavior had testosterone concentrations greater than 100 pg/ml and also had the highest number of Leydig-like cells in their theca. This indicates a possible correlation between testosterone levels, Leydig-like cells’ density, and changes in behavior.
• The remaining seven mares, despite having higher testosterone levels, either took an extended break from their estrous cycle (anoestrus) or exhibited intermittent estrous behavior. This suggests initially that varying degrees of testosterone elevation might impact mares’ reproductive behavior differently.

Exception Case

• The tenth mare, an exception, demonstrated a dominantly different microscopic change involving the proliferation of Sertoli-like cells. The estrogen levels in this mare were the highest amongst the subjects, and the testosterone levels were reported as normal, further affirming that there were no Leydig-like cells observed in this specific mare’s theca.

Condition of Unaffected Ovary

• The study also noted that the unaffected ovary in all the mares was small and inactive, suggesting the diseased ovary’s adverse influence might have led to this condition.
• After the removal of the affected ovary, eight out of ten mares resumed normal cyclic ovarian activity between 115 and 393 days. This pointed towards a recovery in their reproductive function post-ovary removal.