Canine sterilization. Advantages and disadvantages.

Canine sterilization. Advantages and disadvantages.

To sterilize or not to sterilize? Today’s dilemma. We review the advantages and disadvantages of canine sterilization so that you make the best decision for your furry. Remember that the last decision must be made in conjunction with your veterinarian, who will consider the individual characteristics of your dog and the family environment, among other things.

Let’s first look at a summary of the pros and cons of canine sterilization. (Based on a bibliographical review carried out)


1. Control of reproduction and population reduction of stray dogs.
2. Extends life expectancy.
3. Avoid unwanted pregnancy, heat and psychological pregnancy.
4. Avoid Pyometra.
5. Avoid mammary tumors, TVT, perineal, testicular, vaginal, ovarian and uterine tumors.
6. Decreases the appearance of benign prostatic hyperplasia, prostatitis and prostatic cysts.
7. Decreases the probability of suffering from perineal and inguinal hernias.
8. Improves control of diabetes and epilepsy.


1. Increased probability of obesity.
2. Possible joint diseases, especially if castrated at an early age.
3. There is an increase in lymphosarcomas, hemangiosarcomas, mast cell tumors, and osteosarcomas.
4. Increased immune diseases and vaccine reactions.
5. Increases competitive aggressiveness in females, unless it manifests only during heat.
6. It prevents the protective role of testosterone in cognitive dysfunction syndrome (senile dementia) and is therefore contraindicated in these cases.
What is castration?

In simple words, castration is the surgical removal of testicles or ovaries, which results in sterility in our furry dogs, that is, they will not be able to reproduce. Currently, an important debate has been opened about whether or not it is good for your health, but the truth is that today the veterinarian has a more active role in terms of the decision and will make it after carefully analyzing each case. Depending on this analysis and taking into account age, predisposition to diseases, sex, behavior, family environment and other factors, it will be seen if this procedure will bring more benefits than risks or what is the same, if it is advisable or not to carry out out the intervention.

It has been known for years that castration brings multiple benefits to the health of our furry dogs and that it also helps significantly to control their reproduction, which is extremely important in Chile considering the number of abandoned and mistreated animals. But it must be taken into account that the ovaries and testicles produce hormones that have effects on all body tissues and, therefore, the absence of these can somehow impact other body systems, not only the reproductive ones, which can cause hormonal changes. While it is true that in most cases the benefits of castration outweigh the benefits of exposure to sex hormones, this is not always the case.

Aspects to consider

Although it is not yet clear how the absence of hormones produced by the testicles and ovaries influences the body of our furry dogs, there are statistical studies and tests that offer an approximation to the problems that sterilization would generate. Next, we will review the advantages and disadvantages of this type of intervention based on these studies.

1.- Control of the reproduction and therefore of the populations of stray, abandoned and/or mistreated dogs.

2.- It prolongs life expectancy, that is, they live longer. This could be explained by the decrease in behaviors associated with sexual hormones, such as dominant aggressiveness that generates a greater risk of trauma and infections, or by the better care that guardians tend to give who are willing to invest in surgery for furry dogs.

3.- Avoid unwanted pregnancy, heat and pseudo-pregnancy (false pregnancy or psychological pregnancy).

4.- Avoids pyometra (serious infectious disease), which affects approximately 25% of whole bitches before 10 years of age.

5.- Avoid tumors such as transmissible venereal tumors (TVT), perineal tumors and also testicular, vaginal, ovarian and uterine tumors. The latter depend on the hormones produced by the ovaries and testicles.

6.- Significantly reduces the appearance of mammary tumors. 60% are malignant and are more frequent and dangerous the more jealous the dog is. The decrease in their appearance works only if they are spayed before the third heat, but even after, it still increases the survival rate by 45%.

7.- Decreases the appearance of benign prostatic hyperplasia, very common in whole dogs, prostatitis and prostatic cysts.

8.- Decreases the probability of suffering from perineal and inguinal hernias.

9.- Helps to better control diabetes mellitus and the


epilepsy. Progesterone has an antagonistic effect on insulin and stimulates growth hormone, which is diabetogenic, so sterilization is recommended in diabetic and/or epileptic or predisposed dogs.

10.- Changes in behavior: In females, sexual behavior such as attraction to males and marking disappears, and competitive aggressiveness disappears in females that present it during heat. But be careful, if it does not manifest itself exclusively during heat, then castration could worsen the aggression. In castrated males, the effect it has on sexual behavior is relative and in some cases it can greatly reduce mounting, marking and competitive aggressiveness, but in others it does not occur since it will also depend on previous experience.


1.- Risks associated with surgery

2.- Greater probability of obesity: This can be explained because, when castrating, there is a decrease in metabolism and an increase in appetite. Estrogens regulate satiety at the level of the central nervous system. This is relatively easy to manage with a correct diet and exercise regimen.

3.- Neutered dogs show an increase in the rates of certain specific cancers, with the exception of mammary cancer, which is relatively rare in neutered bitches. But care must be taken with this data because, in most cases, it can be explained by the increase in life expectancy since it allows them to have more diseases that appear at an advanced age (many of the studies analyzed do not consider the factor age). However, this is not the case for cancers that present at an early age, such as lymphosarcomas (5.8 years of age), hemangiosarcomas (7.6 years), mast cell tumors (6.3 years) and osteosarcomas.

4.- Immune diseases and vaccine reactions: This could be due to the fact that sex hormones play a very important role on the immune system. For the same reason, they may present more cases of hypothyroidism produced by immune thyroiditis.

5.- Orthopedic alterations: There is no defined scientific evidence on this subject. But it is known that estrogens influence optimal bone growth, so castration should cause the bones to grow more than normal. This fact, together with the frequent weight gain in castrated animals, can theoretically lead to a greater presentation of joint problems such as hip dysplasia, bone fractures, anterior cruciate ligament rupture, etc.

6.- In cases of very early castrations (before 3 months), the incidence of urinary incontinence increases, after 3 months it increases very little and after one year of age it does not influence anything. This can be taken into consideration for predisposed breeds and affects larger dogs more. The same is true for persistent urinary infection for females neutered before puberty.

7.- Behavioral problems: Neutering is contraindicated in a female that has intrasexual or competitive aggression towards people, since it makes it worse, especially if she is neutered before 6 months, except when said aggression manifests itself only when she is in heat which is recommended. Some cases have also been seen where hyperactivity, excitability, shyness and submissive urination increased.

8.- Sterilization is not suggested in case of suffering from cognitive dysfunction syndrome, equivalent to senile dementia in humans, since testosterone has a certain protective effect and slows its progression.

Related Posts

By Lee Chun Hei