WSAVA 2024 Guidelines: Feline Castration and Ovariohysterectomy

Introduction

The World Small Animal Veterinary Association (WSAVA) released comprehensive guidelines in 2024 for the control of reproduction in dogs and cats, published in the Journal of Small Animal Practice. These guidelines represent a significant update to feline sterilization recommendations, emphasizing individualized decision-making while providing detailed surgical protocols for castration, ovariectomy (OE), and ovariohysterectomy (OHE) in cats.

This clinical article synthesizes the key recommendations relevant to feline practice, with particular focus on surgical technique selection, optimal timing, perioperative analgesia, and evidence-based approaches to minimize complications.

Surgical Terminology: Understanding the Distinctions

The WSAVA guidelines purposefully distinguish between three surgical approaches for female sterilization:

Ovariectomy (OE)

Removal of the ovaries only, leaving the uterus in situ. When gonadal hormone loss is the goal and no uterine pathology exists, OE is the preferred procedure according to the guidelines.

Subtotal Ovariohysterectomy (SOHE)

Removal of ovaries and most of the uterus, with ligatures placed on the uterine side of the cervix. The guidelines note that this is what most veterinarians actually perform when they believe they are doing an OHE, as some distal uterine tissue inevitably remains.

Ovariohysterectomy (OHE)

Complete removal of ovaries and entire uterus including the cervix. True OHE is technically more demanding and rarely necessary for routine sterilization.

This distinction becomes critical when considering gonad-sparing surgeries, where precise terminology affects patient outcomes.

Optimal Timing for Feline Sterilization

The Fix by Five Initiative

The guidelines align with the Veterinary Task Force on Feline Sterilization consensus, which recommends that cats not intended for breeding be gonadectomized by five months of age. This recommendation is endorsed by:

• American Veterinary Medical Association (AVMA)
• American Association of Feline Practitioners (AAFP)
• American Animal Hospital Association (AAHA)
• Association of Shelter Veterinarians
• 14 state veterinary medical associations

Evidence for Early Sterilization Safety

A comprehensive literature review found no evidence of increased complications or long-term adverse health effects following sterilization of pediatric and juvenile cats. Key findings include:

• No increased incidence of infectious disease in cats sterilized before 6 months compared to those sterilized later
• No statistically significant difference in outcomes between cats neutered before 4 months versus at or after 6 months
• Minor complication rates were actually lowest in the youngest age group and highest in cats 24 weeks or older
• The traditional concern that early castration predisposes to urinary obstruction in male cats has been disproven

Benefits of Pre-Pubertal Sterilization

Benefit	Evidence
Mammary carcinoma risk reduction	Third most common cancer in cats; risk significantly decreased
Elimination of reproductive emergencies	Prevents pyometra, dystocia
Prevention of unintended pregnancy	Can occur as early as 4 months of age
Decreased urine spraying in males	Castration before 5.5 months associated with reduction
Reduced aggression toward veterinarians	Documented in early-neutered males
Decreased shyness around strangers	Both sexes when gonadectomized before 5.5 months

Surgical Approach: Midline vs. Flank

Midline Approach

Advantages:

• Increased familiarity with regional anatomy for most surgeons
• Better visualization of abdominal cavity if complications arise
• Easier to extend incision if needed
• Preferred for obese patients

Considerations:

• Finding the uterus may take significantly longer
• Standard approach taught in most veterinary curricula

Flank Approach

Advantages:

• Less bleeding reported
• Reduced wound inflammation and infection risk
• Lower risk of wound dehiscence and evisceration
• Smaller incisions possible
• May be advantageous for feral/stray cats where postoperative wound monitoring is difficult
• Shorter time from skin incision to peritoneal entry

Considerations:

• Limited visualization of abdominal cavity if complications occur
• Grid approach less readily expanded than midline
• Must avoid splenic injury
• Obesity may hamper usefulness
• Reaching the cervix may require considerable wound retraction

Evidence from Recent Studies

A December 2024 study in the Journal of Feline Medicine and Surgery compared midline and flank ovariectomy in feral/stray cats (n=38) and found:

• No significant difference in intraoperative nociception between approaches
• Flank approach allowed for smaller incisions
• Flank approach may be preferable for sterilization programs where postoperative wound control is difficult

A 2020 prospective study found no significant difference in pain scores or wound complications between approaches within a teaching environment.

Ovariectomy vs. Ovariohysterectomy

The guidelines note that OE and OHE are equally effective in:

• Preventing reproduction
• Reducing mammary cancer risk

Potential Advantages of OE

• Less invasive procedure
• Less tissue excision and ligation required
• May be simpler and quicker to perform
• Incisions can be made more cranially, potentially improving ovarian visualization
• May reduce risk of ovarian remnant syndrome

Long-Term Outcomes

Both procedures show similar rates of:

• Urinary sphincter mechanism incontinence
• Weight gain
• Long-term complications

Perioperative Pain Management

The WSAVA guidelines emphasize that adequate analgesia is mandatory for all surgical sterilization procedures.

Multimodal Approach

Pain management should be:

1. Pre-emptive: Begin before surgery
2. Intraoperative: Maintained throughout the procedure
3. Postoperative: Continued after surgery

Local Anesthetic Techniques

Local anesthesia is particularly appropriate as it provides:

• Excellent analgesia
• No systemic side effects
• Cost-effective adjunct to systemic analgesia

Recommended Protocols

Agent	Dose	Route	Timing
Meloxicam	0.1-0.2 mg/kg	SC/PO	Pre-operative
Buprenorphine	0.02-0.03 mg/kg	IM/IV	Pre-operative
Bupivacaine	1-2 mg/kg	Local infiltration	Intraoperative
Lidocaine	2-4 mg/kg	Local infiltration	Intraoperative

Note: Always verify current dosing recommendations and ensure no contraindications exist for individual patients.

Antimicrobial Prophylaxis

The WSAVA guidelines provide clear guidance on antibiotic use:

Prophylaxis should be AVOIDED in routine sterilization procedures when:

• Surgery is of short duration
• Performed in a clean environment
• No other factors predispose to infection

If prophylaxis is utilized:

• Use the safest available antimicrobial
• Administer intravenously
• Select low-toxicity, low-cost options
• Follow antimicrobial stewardship principles

This recommendation reflects growing concern about antimicrobial resistance and aligns with responsible antibiotic use guidelines.

Laparoscopic Approaches

The guidelines recommend keyhole or laparoscopic approaches when:

• Available at the practice
• Not cost-prohibitive for the client

Potential advantages include:

• Smaller incisions
• Improved visualization
• Potentially faster recovery
• Reduced postoperative pain

However, traditional approaches remain appropriate for most practices and clinical situations.

Species-Specific Considerations for Cats

Unlike recommendations for dogs (where the guidelines suggest more individualized approaches), for cats the guidelines are more aligned with traditional norms:

Key Points for Feline Practice

1. Doing nothing is generally not recommended for both male and female cats, even with responsible owners
2. Cats are more likely to roam than dogs, increasing unwanted reproduction risk
3. Population control remains a significant concern for feline welfare
4. Benefits of sterilization typically outweigh risks in the cat

Clinical Pearls

• Timing: Sterilize cats by 5 months of age unless specifically intended for breeding
• Technique selection: Choose based on patient factors, surgeon experience, and clinical context rather than dogma
• OE vs. OHE: Both are appropriate; OE may be preferred in absence of uterine pathology
• Approach: Neither midline nor flank is definitively superior; select based on patient and practice factors
• Analgesia: Multimodal, pre-emptive pain management is mandatory, not optional
• Antibiotics: Avoid routine prophylaxis in clean, short procedures
• Documentation: Use precise terminology (OE, SOHE, OHE) in medical records
• Client communication: Discuss timing recommendations proactively with kitten owners

Conclusion

The 2024 WSAVA guidelines provide evidence-based recommendations that support early sterilization in cats while emphasizing individualized surgical approach selection and mandatory multimodal analgesia. The key takeaway for practitioners is that sterilization by 5 months of age is safe, effective, and recommended for cats not intended for breeding, with surgical technique selection guided by patient factors and clinical context rather than tradition alone.

Practitioners should familiarize themselves with these updated guidelines to ensure they are offering current, evidence-based reproductive control options to their feline patients and clients.