About authors

Image of partner

Tierarztpraxis Vierbeiner

This article was written by TOBALIE in cooperation with Tierarztpraxis Vierbeiner

Have you ever wondered what the difference between castration and sterilization is? And why should we actually subject our pets to one of these risky operations? Puppies and little kittens are actually hardly to be surpassed in cuteness or what do you think?

Why birth control? When is it useful?

They are clumsy, gawky and capture us humans with their baby scheme: puppies and kittens. So what would be wrong with letting nature take its natural course? Quite simply, animal welfare! After all, a view at animal shelters reveals that many cats and dogs are still waiting for a loving home. 

When does it make sense? Birth control makes common-sense when the animal is a free mover. Especially if cats are allowed to move around freely. An intact (uncastrated) female cat would reproduce about 80 million cats, over generations, in 10 years. 

Even dogs that are not living on the streets but in human care can “run away” and quickly provide for offspring. If you decide to have contraceptive surgery on your pet, you should consider the timing of the procedure. Early castration can be quite damaging, as the animals are not yet fully developed. In any case, the age and timing of the cycle are essential. Female animals should usually be allowed to go through their first heat. With male animals it is similar. In any case, you should wait for sexual maturity.

Sterilisation versus castration

Sterilization females, castration males? That’s a misconception! During sterilization, the transport of eggs and sperm is prevented. In the process, the spermatic ducts in males and the fallopian tubes in females are either closed, cut or completely removed. Since the gonads (testicles, ovaries) and the uterus are preserved during sterilisation, this surgical procedure has no effect on hormone production. The associated behaviour and biological effects remain with the animal. Only reproduction is inhibited, so no side effects are to be expected.

The situation is different with castration. Here the gonads and sometimes parts of the uterus are removed. The entire reproductive organs are removed from the animal. In male animals this procedure is much easier, because the abdomen does not have to be opened, as in females. A castration is therefore a more extensive operation than a sterilization, which is often associated with more pain. 
Most operations of this kind are castrations, sterilisation is not so frequent. 

One thing in advance: a high percentage of all pet owners are of the opinion that behavioural abnormalities can be eliminated by an operative measure. But this is not true. The elimination of sex hormones can even aggravate certain behaviours (such as anxiety aggression due to increased insecurity). You also always hears of so-called “dominance behaviour” as a reason for castration. Testosterone can play a role, but does not have to. In most cases, the reason for these abnormalities must be sought at the other end of the leash, because a lack of confidence can be reflected in the dog’s behaviour.

Banner App

Costs of castration

You can’t put a price on what you have to pay. As a rule, these operations are more expensive for female animals because they are more complex. If a castration is necessary from a medical point of view (e.g. tumours, purulent uterus), it is possible that a private health insurance for dogs and cats will pay for it.
Please do not try to find the cheapest price, because a proper procedure has its price. If you are negligent, you will have to pay for it later.


This is different for every veterinarian, please ask how it is handled in the respective practice. 
Basically, your animal must be sober before the operation, i.e. it must have had its last meal the day before. 
In most cases, your pet will be given a sedative injection, then will be prepared for the operation (intubated, shaved, etc.) and put under anesthesia. The operation takes on average 20-30 minutes for male animals and up to one hour for females. Here, the size of the animal, the type of operation and possible complications (tissue strongly supplied with blood, etc.) play a role. Afterwards, your treasure will be provided with painkillers and all necessary medication, woken up and allowed to return to your home (usually with a body or neck brace, because the wound must not be licked).

During the next few days your pet should rest in order not to disturb the wound healing. Looking for treats instead of letting off steam is the order of the day. After about 10 days the stitches can be removed and normality returns.  

Castration and its (possible!) advantages and disadvantages

As mentioned above, the gonads are preserved during sterilization. These gonads continue to produce hormones that can influence the behaviour of our beloved pets, which has the advantage of contraception, but no side effects. A castration can also bring advantages from a medical point of view:


  • Safe contraception (no offspring)
  • Gender-specific diseases (false pregnancy, mammary tumours, purulent uterus, testicular tumours, etc.) decreaseThe risk of infectious diseases also decreases considerably
  • Gender-specific behaviour (e.g. hormone-controlled territorial aggression) can be reduced BUT at this point it must be mentioned that surgery can NEVER replace behavioral therapy. If your dog shows conspicuous behaviour, it is recommended to contact a qualified trainer.


  • An operation can always be accompanied by complications (anesthesia, Wound healing disorders etc.)
  • Behaviour patterns, such as anxiety aggression, can be aggravated
  • Too early castrations can have negative effects on the psyche and body
  • Increased appetite, weight gain, obesity (reduce feed in time and observe weight)
  • Disinclination to move
  • Hair structure can change
  • Low risk of incontinence 
  • Risk of bone or spleen tumor slightly increased
  • In most cases, the essence does not change, but unfortunately there is never a guarantee in medicine. 


You see, sterilization is not castration. But both surgical procedures prevent fertilization. There are advantages and disadvantages of castration, but the desire for a change of behaviour should NOT be the reason for castration. It is always an individual decision for each animal and not per se good or bad. Think about what is best for your pet, preferably with experts.