Pathohistological Findings after Bilateral Ovariectomy in Mares with Behavioral Problems.

Area of Science:

• Veterinary Medicine
• Animal Reproduction
• Pathology

Background:

• Behavioral problems in mares often necessitate treatment beyond breeding potential.
• Bilateral ovariectomy (BO) is a successful laparoscopic treatment for these behavioral issues, leading to high owner satisfaction.
• A pathohistological basis for BO's efficacy in improving animal welfare is currently lacking.

Purpose of the Study:

• To pathohistologically evaluate ovaries from mares with behavioral problems (bOE) and compare them to ovaries with granulosa cell tumors (GCT-uOE).
• To investigate potential subclinical causes for behavioral issues in mares undergoing BO.
• To analyze hormonal profiles (AMH, testosterone) and immunohistochemical markers in both groups.

Main Methods:

• Pathohistological examination of bilaterally removed ovaries from mares with behavioral problems (n=20) and neoplastic ovaries (n=10).
• Analysis of clinical data, including serum anti-Müllerian hormone (AMH) and testosterone levels.
• Immunohistochemical analysis of granulosa cells for markers including Ki-67, AMH, aromatase, and others.

Main Results:

• Serum AMH and testosterone were significantly higher in the GCT-uOE group compared to the bOE group.
• Immunohistochemical expression of key markers in granulosa cells did not differ between bOE and GCT-uOE.
• Subclinical findings in bOE included early neoplastic changes (15%) and anovulatory-like follicles (30%).

Conclusions:

• The high success rate of BO (85%) in mares with behavioral problems may be attributed to underlying subclinical neoplastic or anovulatory changes.
• Pathohistological evaluation provides a justification for BO concerning animal welfare in cases of unexplained behavioral issues.
• Further investigation into early neoplastic changes in equine ovaries is warranted.