What is the best age to castrate a dog? – Males and females

Once we make the wise decision to castrate our dog, can we have several questions about the best age to do so? You have certainly heard many versions, and you have seen all sorts of assumptions and experiences that can sometimes confuse us rather than guide us.

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In YourCatCareguide we try to expose, with pros and cons, what is the best age to castrate a dog or a bitch , and what result can we expect as soon as it is submitted to intervention.

You might also be interested in: The best age to castrate a male cat

The Breed And The Best Age To Neuter A Dog

Since reference will be made to castration before the first heat , we try to shorten this time interval, although as already predicted, race influences a lot.

At 6 months of age, very generally and without entering the races, there are still no waves in the bitches, since before ovulation there are always “attempts” that are gaining intensity in the case of females, until ovulation is triggered, when one of these attempts is successful.

In males it is something more complicated to define because there is no heat (we do not “see” when they produce viable spermatozoa), but sexual maturity is used when they become fertile. This is deduced by secondary behaviors like marking territory with urine , lifting to stop urinating, assembling females … We can agree that 6-9 months is a reasonable age to still meet with “puberty” in dogs.

How does the breed influence the ideal age to castrate a dog?

Although they are all of the same species, there is much difference between a chihuahua , for example, and a Neapolitan mastiff. To continue with the comparison, if we have two females of these races, the first will enter, as a general rule, much earlier in estrus than the second. Everything is accelerated when the size of the race is smaller: the heart rate, respiratory rate, metabolism, digestion … and the beginning of reproductive life.

Thus, smaller races are usually earlier in time to reach sexual maturity. However, many things other than race influence, such as the environment, genetics, feeding, presence of nearby stimuli such as a male dog, etc.

We can find Yorkshire breed bitches with their first heat at 5 months, and Dogue de Bordeaux breed bitches that do not appear until they reach a 1 year old, being much more complicated than the opposite. So it is difficult to talk about what months the cio in the bitch will appear, or the fertility if it is male dogs, since each race is a world (even there are bitches that only have an estrus, and is normal), and each dog in particular, a continent. In the trunks, predicting the age at which estrus will appear will become almost impossible.

The best age to castrate a bitch

To briefly address the topic, we will enumerate the advantages and disadvantages of castrating the bitch before the first heat , and so we can compare it with the case of doing so after several years:


  • The risks of undergoing breast tumors in bitches, directly related to the sex hormones produced by the ovaries, are drastically reduced. Bitches castrated before the first heat have an almost zero incidence of breast tumors, only a percentage reserved for genetic possibilities. However, those that are castrated after several cios, should continue to be reviewed periodically in search of the appearance of tumors. The breasts have already undergone the action of hormones.
  • The risks of suffering from pyometra (uterine infections) completely cancel out when the ovaries disappear, responsible for the cyclical stimulation of the uterus, and the same uterus if the surgery is ovary-hysterectomy.
  • The thickness and vascularity (blood supply) to the reproductive organs before the first heat is much lower than after starting to function. The tissues are not infiltrated with fat, and the surgery bands are much safer.
  • There are not usually obesity problems in such young bitches. The presence of excess abdominal fat makes intervention very difficult.
  • It does not stop growth . Contrary to what many people believe, it simply slows down but is sustained over time, meaning the bitch will reach its final adult size a little later than it would for uncastrated bitches.
  • We prevent our bitch from going through unplanned pregnancies, or pseudo-pregnancies (psychological pregnancy) and pseudotolerances, which can affect all bitches two months after heat, even from the first heat.


Possible appearance of urinary incontinence : estrogens appear to be responsible for the correct functioning of urinary bladder and urethral sphincter muscles. By disappearing with ovarian surgery, there will be no estrogens and therefore may appear after a few weeks or months urinary incontinence. They are mild urine losses that occur while the bitch is sleeping, or doing some exercise.

And if you let her have several cios, will not you have urinary incontinence?

Leaving one or two cios to operate, thinking that this way you will not have urinary incontinence after the surgery, is a mistake. Urinary incontinence also appears in medium-breed bitches castrated at 4 years, for example, than in the rest of age ranges. And in addition, it affects a low percentage of castrated females.

Although not castrate, over the years, blood levels of hormones fall (bitches are less fertile), and with this low estrogen, urinary incontinence can also appear, just as it does in humans.

If it does, is there treatment?

There are several drugs that can solve the problem of urinary incontinence, from small amounts of hormones to drugs (phenylpropanolamine), which act as innervation of bladder muscles, and which have already been shown to be effective only in castrated females to treat incontinence .

The best age to castrate a male dog

Here we talk about the advantages and disadvantages of castrating our dog before reaching sexual maturity:


  • We avoid escapes to smell females in heat, since it happens frequently in dogs with a few months, which still do not obey too much, and the hormones are accelerated.
  • We spared the pattern of territory marking that begins to take place systematically, no matter where it is, when it reaches sexual maturity, days without eating when they detect a bitch in the heat in the neighborhood, and the anxiety and / or aggressiveness that can appear in this circumstance.
  • You will not have the constant need to get in trouble at park meetings with other dogs. Its territoriality diminishes or is not developed and the will to seek a fight also, although its character remains the same.
  • The prostate is not influenced by testosterone, which will not suffer from hyperplasia that practically all uncastrated male dogs are at 3-4 years of age.
  • The weight gain we all associate with castration in dogs is less noticeable or goes unnoticed when the operation is done before 12 months of life.
  • Do not get the riding behavior and this is important. Dogs that have learned by observation of other males, or because they were allowed to mount females, may continue with this behavior despite being castrated. Because they have a bone in the penis, dogs do not need the hormones to be able to perform the copulation. If they have acquired the habit, they can mount a female after castrated although, of course, there is no gestation. It is a shorter mount, but the risk of getting herpes virus or suffering the wrath of other males or owners will continue to exist.


Practically, none. Many people believe that your dog will not reach the size you could have as an adult if you had not castrated him at 8 months of age, for example. But if there is no genetic basis, no hormonal stimulation can get a dog to measure or weigh what we want. Muscle development is favored by testosterone, but genetics, combined with proper nutrition and physical exercise , gives rise to practically equal sizes to castrated males at age 3, to say a value.

And the character …

Sometimes, after overcoming the fears of surgery, since there may always be complications in anesthesia, or in the process, as in everything, even though they are minimal, and after taking stock of advantages and drawbacks, someone tells us that our dog will behave childishly, or that his character will change and will no longer be the same if he is castrated before the first heat.

We may hear the same thing if we decide to castrate him when he is several years old, but in the first case, some argue that we will not let the dog do well if he does not receive the influence of the sex hormones. Faced with this, it must be taken into account that the character is defined by genetics, socialization, length of stay with her mother and siblings, surroundings, habits … and that receiving estrogen or testosterone waves in her life will not do with our dog a more balanced animal nor more or less hostile. Hormones can influence but can not determine. We advise you to visit the YourCatCareguide article, which discusses the ideal age to separate the dogs from their mother to understand how important this theme is.

We hope that doubts about the best age for castrating a dog have been clarified, and as we always do, we recommend that you consult your veterinarian about each particular case, since we can not always apply generalizations to our dog or bitch despite of the same work with the other congeners.

See also our article on post-castration care .

This article is purely informative, in YourCatCareguide.com.br we do not have the capacity to prescribe veterinary treatments nor to make any type of diagnosis. We suggest that you bring your pet to the veterinarian in case of any type of condition or malaise.

If you want to read the similar articles to What is the best age to castrate a dog? – Males and Females , we recommend you to enter our Prevention section .

    Emily Harris

    Hi Guys, Girls, and Cats:-pI am Emily Harris, and you can see in above pic. She loves me I swear. I saved her from a dumpster a few weeks back.

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