Breeding Soundness Examination of the Mare

What is Breeding Soundness? Why is it Performed?

• Breeding Soundness Examination (BSE): A comprehensive medical and reproductive assessment of a mare's suitability for breeding.

• Purposes of BSE:

  • Identify potential reproductive issues or anatomical abnormalities that could impact conception, pregnancy, or birthing.

  • Assess fertility potential prior to entering a breeding program.

  • Optimize breeding efficiency.

  • Determine suitability for natural mating, artificial insemination (AI), or embryo transfer.

  • Minimize economic losses by selecting mares with a high chance of successful reproduction.

Importance of Breeding Soundness Exam

• Ensures stallions and mares are capable of reproduction.

• Early identification of fertility issues to prevent breeding failures.

• Enhances breeding efficiency and economic returns.

• Evaluates reproductive anatomy, semen quality, and overall health.

• Crucial for breeding programs, performance horses, and genetic selection.

Components of the Breeding Soundness Exam

1. Comprehensive History:

   • Gather background information on the mare's health and reproductive history:

     • Age, previous medical conditions, vaccination records, feeding program.

     • Estrous cycle history: onset of heat, frequency, last cycle.

     • Breeding history: attempts to achieve pregnancy, methods used.

     • Pregnancy and foaling history: last foaling, complications, lactation, pregnancy losses.

2. Physical Examination:

   • General physical check, including vital signs and musculoskeletal assessment.

   • Evaluate mammary glands for signs of mastitis, infection, or tumors.

3. External Vulvar Examination:

   • Assess vulva structure, alignment, apposition, and tone, ideally vertical to anus.

4. Rectal Palpation:

   • Internal examination to assess size, shape, and tone of cervix, uterus, and ovaries using rectal palpation under standing sedation.

5. Rectal Ultrasound:

   • Detailed assessment of reproductive organs via ultrasound conducted through the rectum.

   • Helps determine the stage of the heat cycle and identifies hard-to-feel issues.

6. Vaginal Speculum Examination:

   • Uses a cardboard tube to inspect the vagina interior for scarring and infection.

7. Uterine Cytology:

   • Examines a sample from the endometrium for infections or abnormalities.

   • Indications of inflammation correlate with lower pregnancy rates.

Restraint and Medication

• Techniques for restraining mares during exams:

  • Halter and lead rope, twitch (lip/ear), stocks, holding up a leg, chemical restraint (sedation).

  • Utilize sedatives, analgesics, and antispasmodics as needed.

Endometrial Biopsy

• A procedure that involves taking a sample of the endometrium for microscopic examination to detect abnormal cells or disease.

• Procedure:

  • Cleanse the perineum, don sterile covering, and use gloved hands to introduce the biopsy instrument.

  • Clamp onto the uterine wall, retract to obtain a tissue sample, and preserve in Bouin's fixative for analysis.

Grading of Endometrial Biopsy

• Grading based on inflammation, glandular nesting, and fibrosis:

  • Grade I: Normal, mild focal inflammation – ~80% chance of successful pregnancy.

  • Grade IIa: Mild/moderate inflammation – ~50-80% chance of successful pregnancy.

  • Grade IIb: Moderate inflammation – ~10-50% chance of successful pregnancy.

  • Grade III: Severe inflammation – <10% chance of successful pregnancy.

Vaginal Examination

• Steps include cleaning, rinsing, and drying the perineum.

• Use a speculum to view the cervix and vaginal wall; cervix reflects hormonal status (estrogen vs. progesterone levels).

Reproductive Issues Found in BSE

• Endometritis: Inflammation or infection of uterine lining, common cause of infertility; symptoms include vulvar discharge and cyclic inflammation.

• Uterine Cysts: Fluid-filled structures in the uterus caused by lymphatic blockage, scarring, or chronic inflammation.

• Fibrosis: Scarring and thickening of the uterine lining due to chronic inflammation or trauma.

Advancements in Equine Reproduction Exams

• Artificial Insemination (AI): Advances in semen preservation and transport techniques.

• Embryo Transfer (ET): Allows high-value mares to produce multiple foals.

• Intracytoplasmic Sperm Injection (ICSI): Enhances fertilization for subfertile stallions.

• Genetic Testing & Hormonal Analysis: Provide insights on fertility potential.

• Advanced Imaging: Enhanced ultrasound and endoscopy techniques for reproductive assessments.