Dog desexing: how Australian vets choose the timing

Deciding whether and when to spay or neuter a dog is not as simple as picking a surgery date. In a newly published Australian survey, most responding veterinarians recommended routine desexing, but the timing they advised depended on factors including the dog's expected adult size, breed and the owner's circumstances.^[1]

Behavior was also a prominent reason for recommending surgery, especially for male dogs.^[1] For trainers and owners, that finding raises a useful question: when someone expects desexing to improve behavior, exactly which behavior do they mean?

The study, published in the Australian Veterinary Journal on October 16, 2026, collected online responses from 107 Australian veterinarians between March and November 2025.^[1] It describes what vets said they recommend and do, rather than tracking what happened to dogs after surgery.^[1]

Broad support, different timing

The Melbourne Veterinary School research team reported that 93.6% of respondents to the routine-desexing question recommended it.^[1] Preventing unwanted mating, perceived health benefits and population control were common reasons given.^[1]

Agreement on the general recommendation did not produce one timetable for every dog. Larger expected adult size was associated with a later recommended age of desexing.^[1] Vets also identified breed and owner preference among the factors shaping their advice, while written responses mentioned matters such as an owner's ability to confine a dog, finances, temperament and whether the setting was a charity or private practice.^[1]

For female dogs, the results section reported that 59.3% of those answering the heat-cycle question recommended waiting until after one season, while 40.7% recommended desexing before the first.^[1] That is a split in reported advice, not a finding that either timetable produced better health outcomes.

The Australian Veterinary Association's policy provides useful context: it calls for decisions about the procedure and timing to be made case by case, with the owner, using the individual animal's risks and benefits and current evidence.^[2] The survey gives a glimpse of how that conversation takes shape in practice.

Reasons for surgery and possible consequences

Preventing an unwanted litter, managing a hormone-related behavior and weighing future health risks are different goals. The 2012 review Effects of Surgical Sterilization on Canine and Feline Health and on Society separates population-level aims from the potential benefits and drawbacks for individual animals, and stresses that the strength of the evidence and breed predispositions matter.^[3]

Breed-specific research provides one example. A study comparing Labrador and Golden Retrievers used veterinary hospital records and found that associations between neutering and certain joint disorders and cancers differed by breed and sex.^[4] Those findings give context for an individual discussion, rather than establishing one surgery age that is best for every dog.^[4]

Behavior is a reason, not a measured result

Asked why they would recommend desexing, 86.7% of respondents to that question selected preventing or managing unwanted behavior for male dogs, compared with 57.3% for female dogs.^[1]

Those percentages deserve careful reading. They are percentages of veterinary responses, not percentages of dogs whose behavior improved. The questionnaire used the broad category “prevent or manage unwanted behaviours”; it did not establish which specific problems each vet had in mind or measure the effects of surgery.^[1]

In their discussion of earlier research, the authors distinguish findings about libido, roaming and marking from the less consistent evidence concerning aggression.^[1] They also note that reported behavioral outcomes vary with context.^[1] Those are background observations, not new behavioral results from this survey.

For a closer look at those behavioral questions, McGreevy and colleagues' 2018 study in the Knowledge Base analyzed owners' reports of male dogs' behavior and found that associations with the timing of castration and the estimated proportion of life spent intact differed across behaviors, including marking, fearfulness and aggression.^[5] It was an observational questionnaire analysis, not a randomized surgery trial, so it does not show that neutering will cause or prevent aggression in a particular dog.^[5]

For an owner bringing a behavior concern to a vet, a more useful question than “Will neutering make my dog better behaved?” might be: “Which behavior are we trying to change, and what evidence supports expecting that change in this dog?” A trainer can contribute specific observations to that discussion without turning a broad survey category into a promise about surgery.

The operation and recovery matter, too

The survey went beyond the decision to desex. Traditional castration and removal of both the ovaries and uterus remained the dominant procedures reported, while alternatives such as vasectomy and ovary-sparing surgery were rarely performed.^[1] The authors identified a gap between recognizing some alternatives as suitable in selected cases and actually using them, but did not establish why that gap existed.^[1]

They also raised questions about relatively infrequent use of local anesthetic blocks as part of pain management.^[1] That should not be confused with dogs receiving no pain relief: the survey also recorded use of opioids and postoperative anti-inflammatory medication, and did not measure patients' pain or recovery.^[1]

These findings offer further questions for a consultation: why is a particular procedure being recommended, what will pain management involve, and what should the owner expect during recovery? The survey does not tell an individual owner which operation or drug protocol to choose.

A snapshot, not a new rulebook

Participation was voluntary, recruitment used professional networks and social media, and Victoria was overrepresented.^[1] All questions were optional, so the number answering varied; the age-by-size figures, for example, were based on 72 respondents rather than all 107.^[1] These results should not be treated as a precise national tally, and the one-time survey cannot establish how practice has changed over time.^[1]

Its contribution is a detailed picture of the decisions being reported by this group of veterinarians. For owners and trainers, the useful next step is a clearer conversation about the particular dog: the purpose of surgery, the reason for the proposed timing and the outcomes that can reasonably be expected. Individual medical decisions belong with the veterinarian who knows the animal.

Readers can explore these papers and other related resources together in the Knowledge Base's Spay/Neuter collection.