Neutering reliably prevents a dog or cat from reproducing. It is best decided early — between six months and a year of age — and in females, doing it before the first season greatly reduces the risk of mammary tumours. It does not change the animal’s personality and it does not rob it of its instincts: those are myths.
Key facts:
- What it is: making a fertile animal infertile, medically (hormones, reversible) or surgically (permanent).
- When to decide: roughly between 6 months and a year of age.
- Key benefit in females: done before the first season, it greatly reduces mammary tumours.
- Especially advisable in cats: feline mammary tumours are highly malignant.
- Drawbacks: surgical and anaesthetic risk; it is irreversible; they may gain weight.
- Myths: “it changes their personality”, “they become lazy”, “every female should have one litter”.
As soon as the first signs of sexual maturity appear, so do the doubts. Should we neuter? Is it good for her? There is a great deal of folklore around this subject, so it is worth making the decision on reliable information.
What is neutering?
It means making an animal that was fertile no longer fertile. There are two routes: medical (hormonal), which is reversible, and surgical — removal of the ovaries and uterus, or of the testicles — which is permanent.
What are the benefits in a bitch?
She will not have litters. Removing the ovaries and uterus prevents diseases of those organs, such as pyometra and tumours. And if it is done before the first season, or between the first and the second, it greatly reduces the likelihood of her developing mammary tumours.
The drawbacks: as with any surgery there is a surgical and anaesthetic risk; some bitches may develop urinary incontinence afterwards (usually manageable with appropriate treatment); and it is irreversible.
And in a queen (female cat)?
The benefits are the same as in the bitch, with one important difference: feline mammary tumours are highly malignant, so in cats neutering is especially advisable. The drawbacks are the same too, although incontinence is not usually a problem in cats.
What are the benefits in a male dog?
The procedure may be orchiectomy (removal of the testicles; the dog stops producing testosterone) or vasectomy (division of the vas deferens; the testicles remain). It prevents unwanted matings, reduces fighting with other males and the tendency to escape in search of females, and lowers the likelihood of prostate problems, neoplasia and orchitis. Neutered males also tend to be more focused on their owners.
A caveat on vasectomy: because the testicles remain, it does not prevent the problems caused by testosterone.
And in a tomcat?
The male cat marks with urine, which has a strongly unpleasant smell, and tends to escape in search of females. Castration resolves or at least greatly reduces both problems; vasectomy does not. And because he roams less, he is exposed to fewer fights — and to the diseases that fights transmit.
What are the myths about neutering?
“It will change their personality.” It will not: the operation does not alter their essential nature. “They’ll spend all day lying down.” Dogs are more or less active according to their temperament, not according to surgery. “Every female should have at least one litter.” There is no medical justification for this whatsoever — on the contrary, females neutered before the first season have a far lower risk of mammary tumours. “My cat will lose his instincts.” Neutered cats tend to be more affectionate and calmer, and they do not lose their hunting instinct.
What about contraceptive treatments?
They exist, but they bring problems. Tablets must be given exactly as directed to avoid adverse effects. Injections are given by the vet at the right moment and can be painful, so the animal remembers and becomes progressively harder to inject. If it is clear the animal is not going to be bred from, neutering is the better option.
Frequently asked questions
When should I neuter my dog or cat?
The decision is best made between six months and a year of age. In females, before the first season greatly reduces mammary tumour risk.
Will neutering change my pet’s character?
No. That is a myth: it does not alter their essential nature or their basic instincts.
Do neutered pets get fat?
They can gain weight, so increase exercise and adjust the food to their new requirements.
Is vasectomy better than castration?
Vasectomy does not prevent testosterone-driven problems — marking, roaming, prostate disease — because the testicles remain.
Pyometra or a mammary tumour means emergency surgery and a substantial bill. Petplan España (Petplan Ibérica, S.L.) reimburses 100% of the vet bill up to €3,100 a year, with a €45 excess, at any vet you choose, provided it is not a pre-existing condition. See the policy terms.
