Neutering in Dog

Introduction

Neutering refers to ovariohysterectomy (OHE) (surgical removal of the ovaries and uterus), ovariectomy (OVE) (surgical removal of the ovaries alone), and orchiectomy (surgical removal of the testicles). It is a common veterinary practice for population control, health benefits, and behavior management. Neutering procedure in male dogs called castration or orchidectomy (removal of testicles).

Indications of Neutering 

Population Control: Reduces overpopulation by inhibiting male fertility.

Behavioral Benefits:

• Decreases male aggressiveness.
• Reduces roaming tendencies.
• Minimizes undesirable urination behavior (marking)

Prevention of Androgen-Related Diseases:

• Prostatic diseases.
• Perianal adenomas.
• Perineal hernias.

Medical and Surgical Indications:

• Congenital abnormalities.
• Testicular or epididymal abnormalities.
• Scrotal neoplasia.
• Trauma or abscesses.
• Inguinal-scrotal herniorrhaphy.
• Scrotal urethrostomy.

Other Clinical Benefits:

• Epilepsy control.
• Control of endocrine abnormalities.

Preoperative Management

Reproductive surgery in male dogs includes procedures to control reproduction, treat reproductive diseases (e.g., testicular tumors, prostatitis, prostatic abscesses), and stabilize systemic conditions like diabetes and epilepsy. Neutering prevents unwanted behaviors and reconstructs damaged tissues. Diagnosis relies on clinical signs, imaging (radiography, ultrasound, CT, MRI), endoscopy, and lab tests (cytology, microbiology, hormonal assays, hematology, biochemistry, urinalysis).

Male Dog Reproductive Evaluation:

Physical Examination
Abdominal and rectal palpation assess prostatic size, texture, and lymph nodes. Pain may indicate prostatitis. The scrotum, testicles, penis, and prepuce are examined for size, symmetry, masses, trauma, or congenital defects.

Clinical Pathology
Prostatic fluid analysis, obtained via ejaculation, prostatic wash, or fine-needle aspiration, detects infections, neoplasia, or inflammation. Cytology of masses and bacterial cultures aid in diagnosis. Biopsy confirms testicular, prostatic, penile, or scrotal abnormalities.

Hormone Analysis
Serum testosterone (<100 pg/mL) confirms neutering. In intact males, testosterone ranges from 0.5–9 ng/mL, while estrogen remains below 15 pg/mL. Hormonal fluctuations make interpretation variable.

Diagnostic Imaging
Radiographs assess prostatic size, shape, and metastasis. Contrast studies help evaluate prostatic reflux. Ultrasound detects prostatic and testicular abnormalities (e.g., cryptorchidism, torsion, neoplasia). Bone scans and thoracic radiographs help stage prostatic cancer.

Other Tests
Cystometrograms and urethral pressure profiling may assess urinary incontinence but are rarely performed.

Considerations in neutering

1 Preoperative considerations

• HCT (Hematocrit)
• TP ( total protein)
• In patients >5–7 y, consider electrolytes, liver enzymes, BUN, and Cr

Premedication

• Diazepam (0.2 mg/kg IV)
• Hydromorphone (0.05–0.2 mg/kg IV, IM in dogs; 0.05–0.1 mg/kg IV, IM in cats)

2 Intraoperative considerations

Induction

If premedicated, give: • Propofol (2–4 mg/kg IV), or  • Alfaxalone (2–3 mg/kg IV)

If not premedicated, give: • Propofol (4–8 mg/kg) IV), or • Alfaxalone (2–5 mg/kg IV)

Maintenance

Isoflurane or sevoflurane, plus

Fentanyl (2–10 µg/kg IV PRN in dogs; 1–4 µg/kg IV PRN in cats) for short-term pain relief, plus

Hydromorphone (0.05–0.2 mg/kg IV PRN in dogs; 0.05–0.1 mg/kg IV PRN in cats) , plus

Ketamine (low dose; 0.5–1 mg/kg IV),

Fluid needs

Estimated blood loss(EBL)

• 5–10 mL/kg/h plus 3× EBL
• 10–20 mL/kg/h plus 3× EBL if open abdomen

Monitoring

• Blood pressure
• HR
• ECG
• Respiratory rate
• SpO2
• Temperature
• EtCO2

3 Postoperative Considerations

Analgesia

•   Carprofen (2.2 mg/kg q12h PO), or
•  Deracoxib (3–4 mg/kg q24h for <7 days PO), or
• Meloxicam (0.1–0.2 mg/kg once SC, PO then 0.1 mg/kg PO q24h)

Monitoring

• SpO2
• Blood pressure
• HR
• Respiratory rate
• Temperature

Procedures for Neutering in Dogs

Prescrotal Castration Procedure

1   Patient Positioning & Preparation:

• Place the patient in dorsal recumbency.
• Confirm the presence of both testicles in the scrotum.
• For the abdomen and medial thigh clean and clip them aseptically.
• Avoid irritating the scrotum with clippers or antiseptics.
• Drape the surgical area, excluding the scrotum from the field

2   Testicle Exteriorization:

• Apply gentle pressure on the scrotum to push one testicle into the pre-scrotal area.
• Make a midline incision along the median raphe over the displaced testicle.
• Incise subcutaneous tissue and spermatic fascia to exteriorize the testicle.
• Carefully incise the parietal vaginal tunic, avoiding the tunica albuginea

3  Cord Ligation & Testicle Removal:

• Place a hemostat on the vaginal tunic near the epididymis.
• Digitally separate the ligament of the tail of the epididymis while maintaining traction.
• Further, exteriorize the testicle, and identify the spermatic cord structures.
• Ligate the vascular cord and ductus deferens separately, then apply an encircling ligature around both.
• Use 2-0 or 3-0 absorbable suture (e.g., Vicryl, PDS, Monocryl, Maxon, or Biosyn).
• Clamp the spermatic cord near the testicle, grasp the ductus deferens, and transect both.
• Inspect for hemorrhage and replace the cord within the tunic.
• Encircle the cremaster muscle and tunic with a ligature.

4   Second Testicle Removal:

• Advance the second testicle into the incision.
• Repeat the same procedure for removal.

5   Wound Closure:

• Approximate the dense fascia on either side of the penis with interrupted or continuous sutures.
• Close subcutaneous tissue using a continuous pattern.
• Use intradermal or simple interrupted sutures for skin closure.

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Closed Prescrotal Castration Procedure

1. General Approach:

Similar to open castration, the parietal vaginal tunic remains intact.

The testicle and spermatic cord are exteriorized without incising the tunic.

2. Exteriorization of the Testicle:

Reflect fat and fascia from the parietal tunic using a gauze sponge.

Apply traction on the testicle while tearing fibrous attachments between the spermatic cord tunic and scrotum.

3. Ligation & Testicle Removal:

Clamp the spermatic cord just distal to the testicle using a hemostat.

Place an encircling ligature around the entire spermatic cord and tunics using 2-0 or 3-0 absorbable sutures (e.g., Vicryl, PDS, Monocryl, Maxon, or Biosyn).

Apply a second transfixion ligature, either:

Through the cremaster muscle or

• Between structures within the tunic, proximal or distal to the first ligature.
• Transect the cord between the distal ligature and the hemostat.
• Inspect for hemorrhage before releasing the stump.

4. Removal of the Second Testicle:

Advance the second testicle into the incision and follow the same procedure.

5. Wound Closure:

Close the subcutaneous tissue using a continuous suture pattern.

Oppose the skin with either intradermal or simple interrupted sutures.

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Perineal Castration Procedure

1. General Approach:

Performed similarly to open prescrotal castration, but with a perineal incision.

The open technique is required as testicles are harder to displace into a caudal incision.

2. Incision Placement:

Make a midline incision through the skin and subcutaneous tissue.

The incision is dorsal to the scrotum and ventral to the anus in the perineal region.

3. Exteriorization of the Testicle:

Gently advance one testicle into the incision.

Incise the spermatic fascia and vaginal tunic to expose the testicle.

4. Ligation & Testicle Removal:

Fully exteriorize the testicle by applying controlled traction.

Identify and ligate the spermatic cord, following the open or closed pre scrotal technique.

Transect the spermatic cord and inspect for hemorrhage before replacing the stump.

5. Second Testicle Removal:

Advance the second testicle into the incision and repeat the procedure.

6. Closure:

Suture the subcutaneous tissue using a continuous pattern.

Close the skin with intradermal or simple interrupted sutures.

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Scrotal Ablation Procedure

Scrotal ablation is a surgical procedure where the entire scrotum is removed, often performed in animals alongside castration.

1. Indications:

• Neoplastic scrotal diseases (e.g., tumors).
• Scrotal urethrostomy in dogs and perineal urethrostomy in cats.
• Severe trauma, abscesses, or ischemia of the scrotum.
• Cosmetic improvement for dogs with a pendulous scrotum.

2. Surgical Approach:

• Elevate the scrotum and testicles from the body wall.
• Make an elliptical skin incision at the base of the scrotum, ensuring minimal excess skin removal.

3. Hemostasis & Castration:

• Control hemorrhage using electrocoagulation, ligation, or direct pressure.
• Incise the vaginal tunics and remove the testicles using either:
• Open castration technique, or
• Closed castration technique (as an alternative).
• 4. Scrotum Removal:

Incise the median septum of the scrotum and remove it completely.

5. Closure:

Subcutaneous tissue: Use a simple continuous pattern with 3-0 absorbable sutures.

Skin closure: Use either:

• Interrupted sutures with 3-0 or 4-0 nonabsorbable sutures, or
• Intradermal suture pattern for a smoother closure.

Complications of Neutering(castration) 

• Hemorrhage
• Scrotal hematoma
• Scrotal bruising
• Infection
• Dehiscence
• Urinary incontinence
• Behavior change
• Eunuchoid syndrome

• Will neutering change my dog’s personality?
  No, but it can reduce hormone-driven behaviors like roaming and marking.

• Will my dog gain weight?
  Only if diet and exercise aren’t managed properly.

• How long is the recovery?
  10–14 days, with full internal healing taking up to a month.

• Can my dog still reproduce right after surgery?
  Yes, sperm can remain for weeks—keep him away from females in heat.

• Will neutering stop humping?
  It may reduce it, but training is still needed for habit-driven humping.