Vet’s 2025 Guide to Equine Cryptorchidism – by Dr Duncan Houston

⚠️ Vet’s 2025 Guide to Equine Cryptorchidism

By Dr Duncan Houston BVSc

1. What Is Cryptorchidism?

Cryptorchidism occurs when one or both testicles fail to descend into the scrotum—a condition seen in ~5–8% of male foals, especially in Quarter Horses, Saddlebreds, Percherons, ponies and crosses :contentReference[oaicite:3]{index=3}. A unilateral rig has one retained testicle; a bilateral rig has both undescended.

2. Why It Matters

• Retained testicles produce testosterone, so rigs still display stallion behavior—aggression, marking, libido :contentReference[oaicite:4]{index=4}.
• Undescended testicles often lose fertility due to higher abdominal temperature but can still produce hormones :contentReference[oaicite:5]{index=5}.
• Retained testes carry higher risks of torsion or tumor development :contentReference[oaicite:6]{index=6}.
• The condition is heritable; breeding affected animals is discouraged :contentReference[oaicite:7]{index=7}.

3. Causes & Risk Factors

Results from a mix of genetic, hormonal, and mechanical factors—failure of gubernaculum regression or hormonal signaling during fetal development :contentReference[oaicite:8]{index=8}.

4. Signs & Diagnosis

4.1 Palpation & History

• At birth, both testicles should descend; if one or both are absent by 24 months, cryptorchidism is likely :contentReference[oaicite:9]{index=9}.
• Rectal or external palpation under sedation may locate the retained testis :contentReference[oaicite:10]{index=10}.

4.2 Imaging

Ultrasound—transabdominal or inguinal—helps locate the undescended testicle :contentReference[oaicite:11]{index=11}.

4.3 Hormonal Testing

• Testosterone, estrone sulfate (>3 yr olds), and anti‑Müllerian hormone (AMH) help distinguish cryptorchid from gelded :contentReference[oaicite:12]{index=12}.
• AMH is reliable: detectable in intact and cryptorchid stallions, absent in geldings :contentReference[oaicite:13]{index=13}.

5. Treatment Options

5.1 Cryptorchidectomy

The definitive treatment is surgical removal of the retained testicle. Methods include:

• Standing laparoscopy: Minimally invasive, outpatient-friendly :contentReference[oaicite:14]{index=14}.
• Flank/paramedian laparotomy: Open abdominal approach for deeply located testes :contentReference[oaicite:15]{index=15}.
• Inguinal approach: Suitable for testes retained near scrotal canal :contentReference[oaicite:16]{index=16}.

During surgery, tetanus prophylaxis, NSAIDs, and antibiotics (if abdominal entry occurs) are essential :contentReference[oaicite:17]{index=17}.

5.2 Outcome & Fertility

• Removing both testes yields sterility; unilateral removal may leave some fertility :contentReference[oaicite:18]{index=18}.
• Post-op prognosis is excellent with low complication rates :contentReference[oaicite:19]{index=19}.

6. Post-Operative Care & Complications

• Restrict exercise briefly, monitor incision and check for hemorrhage, funiculitis, peritonitis, or hernias :contentReference[oaicite:20]{index=20}.
• Prognosis is generally good following laparoscopy or open surgery :contentReference[oaicite:21]{index=21}.

7. Breeding & Herd Management

• Because cryptorchidism is heritable, affected horses should not be used for breeding :contentReference[oaicite:22]{index=22}.
• Registration bodies often restrict listing rigs :contentReference[oaicite:23]{index=23}.
• Consider early inspection of breeding stock and vans :contentReference[oaicite:24]{index=24}.

8. Behavioral Considerations

Cryptorchid horses often remain aggressive, display sexual behavior, and are harder to geld until the retained testicle is removed :contentReference[oaicite:25]{index=25}.

9. Ask A Vet Support 🩺

At Ask A Vet, we assist by:

• Interpreting hormone test results (AMH, testosterone, estrone sulfate).
• Guiding imaging—palpation vs ultrasound diagnostics.
• Planning surgical approach—laparoscopy vs laparotomy.
• Post-op monitoring—incision, behavior, healing.
• Advising on breeding rights, registries, and herd planning.

Download the Ask A Vet app today for tailored cryptorchidism support and confident equine management in 2025 and beyond! ❤️

10. Quick Reference Table

11. Final Thoughts

Equine cryptorchidism is a manageable condition with excellent surgical solutions. Early detection, appropriate surgical planning, and post-op care lead to strong long-term outcomes. Ask A Vet offers expert guidance from diagnosis to recovery, empowering you to make structured decisions for your horse’s health and future in 2025. ❤️