Elective surgical sterilization timing

WSAVA guideline

Key findings

• Bitch mammary tumours: intact 8.4–52% vs spayed 1.8% (4.9–5.3% if >2 yr); ~50% malignant; Schneider 1969 RR 0.5% prepubertal, 8% 1st–2nd, 26% 2nd–3rd, none after 3rd; Beauvais 2012: weak evidence (4.1.1.4).
• Queen mammary tumours: >80% malignant; gonadectomy <6 months cuts incidence 91%; no effect after 8/24 months; Siamese/Oriental ~2× (4.3.1.2.2).
• Pyometra: >20–54% of female dogs by 10 years where gonadectomy is therapeutic-only; queens 2.2% by 13 yr (fatality 5.9%) (4.1.1.2, 4.3.1).
• USMI: 5–20% of spayed females (males 0.94%); ↑ risk ≥25 kg with early gonadectomy; <3–6-month threshold evidence weak (5.1.2).
• Orthopaedics: gonadectomy <6–12 mo (retrievers, GSD) → joint disease 2–5× intact; male goldens <6 months 5× HD + CCL rupture; Dachshund IVDD ↑ <12 months (5.1.3, 5.2.3).
• Cancer: osteosarcoma 2×; lymphoma 4.3× (female vizslas) / 3× (male goldens <12 mo); haemangiosarcoma 5× / 9.2×; MCT 2.6× in 20–30 kg dogs (5.1.1, 5.2.1).
• OE vs OVH: textbook "OHE" at the uterine body is anatomically an SOHE; OE preferred absent uterine pathology — quicker, fewer complications (S1).
• Timing: bitches ideally spayed after first/second heat, not in oestrus (delay 2 months or P4 <2.0 ng/mL; queens may be spayed in oestrus); dog paediatric gonadectomy discouraged (owned animals); cats 3–4 months (5.1.7, 5.3.5).
• Tables 11–12 matrix: large/giant breeds + responsible owners → intact or hormone-sparing surgery (hysterectomy/vasectomy); feral bitches → hysterectomy not recommended (fatal peritonitis if bred); orchiectomy for ferals; GnRH implant without surgical infrastructure.
• Life expectancy: spayed females +23% lifespan (Banfield, 2.2 M dogs); Rottweilers intact ≥4.3 yr +17 mo vs spay <1 yr −1.5 yr; gonadectomised cats +1–4 yr (4.1.4, 4.3.4).

Drugs named in WSAVA’s own guideline text

As printed in WSAVA’s document, not this app’s own extracted data — see “Related drugs in this reference” below for that.

• Cefazolin (Dog + cat)

• Local anaesthetics (IP, incisional, intratesticular, ovarian, port-site) (Dog + cat)

• Phenylephrine (Dog)

• Silver nitrate (Cat)

• Oestradiol benzoate (Bitch)

• Vincristine sulphate (Dog)

• Insulin (Bitch)

Recommendations

• Neutering decisions case-by-case (species, sex, breed, size, owner)

  "can no longer be supported for all categories" — Expert consensus (WSAVA)

• Hormone loss acceptable, no uterine pathology → OE preferred; OHE for uterine disease/pregnancy

  Committee position ("OE is the preferred procedure")

• Bitches spayed after 1st/2nd heat; avoid oestrus (2 months or P4 <2.0 ng/mL)

  Expert consensus (WSAVA)

• Dogs: paediatric gonadectomy discouraged (owned animals); cats: 3–4 months recommended

  Expert consensus (WSAVA)

• Large/giant breeds at risk: leave intact or offer hysterectomy/vasectomy

  Expert consensus (WSAVA, Tables 11–12)

• Intact males: andrological monitoring yearly from 40% of life expectancy; GnRH trial before orchiectomy (behaviour)

  Expert consensus (WSAVA)

• Prophylaxis unwarranted for clean procedures; multimodal analgesia mandatory

  Expert consensus (WSAVA)

Related drugs in this reference (3)

The quoted line under each drug is its own already-extracted indication text that matched this condition — the reason it’s listed, not a paraphrase. Open a drug for its full species/route breakdown, calculator, and complete adverse-effect list.

Showing 3 of 3 linked drug records. Open a record for species, route and source details.

• MELOXICAM

  “Single-dose post-op pain (ovariohysterectomy, orthopedic, castration)”

  Source dose preview: 0.2 mg/kg loading, then 0.1 mg/kg, q24h, PO/SC/IV (Dog)

  Adverse-effect notes: GI (vomiting, diarrhea, ulceration) — Most common · Renal injury — Reported at ≥0.3–0.5 mg/kg and higher (dog); with repeated/dehydrated dosing (cat)

• PHENYLPROPANOLAMINE

  “Urethral sphincter mechanism incompetence (spay incontinence) — first-line medical therapy; retrograde ejaculation (3–4 mg/kg q12h)”

  Source dose preview: 1–2 mg/kg (12.5–50 mg total), q8h (or 1.5 mg/kg q8–12h), PO (Dog)

  Adverse-effect notes: Restlessness, anxiety, irritability, anorexia — Common · Hypertension, tachycardia, urine retention — Dose-related

• ROBENACOXIB

  “OstiRobe Injection is indicated for the control of postoperative pain and inflammation associated with orthopedic surgery, ovariohysterectomy and castration in…”

  Source dose preview: 1–2 mg/kg, q24h, PO (Dog)

  Adverse-effect notes: GI (vomiting, soft feces, diarrhea) — Most common, usually mild/self-limiting · ↑ Liver enzyme activity — With long-term oral use (not always associated with pathology)