Side effects of spaying a dog

This blog will talk about the adverse effects of spaying female dogs. Castration is a procedure used by several veterinarians due to the great benefits for dogs’ health and public health, but what would be the adverse effects of neutering a dog?

Side effects of spaying a dog

Dog castration causes it to lose its major source of sexual hormone production, due to surgical removal of the gonads. With the reduction of sex hormones, several benefits can be had, but in recent studies some adverse effects have been observed. 

Spaying dogs can have adverse effects such as:

  • Increased incidence of orthopedic diseases;
  • Increased occurrence of tumors;
  • It favors the weight.

Increased incidence of orthopedic diseases

In general, early castration in large dogs can be more harmful because research has observed an increase in the incidence of joint diseases such as hip dysplasia, rupture of the cranial cruciate ligament and elbow dysplasia in spayed dogs.

Precociously spayed dogs, in animals less than 6 months old, are the most affected by these diseases, and may be twice as likely to have these orthopedic diseases when compared to non-spayed dogs.

Increased occurrence of tumors

Spaying a female dog has been used for many years as a way of preventing breast tumors. However, in some breeds such as Golden Retriever, Labrador, Boxer and Rottweiler, an increase in the incidence of tumors such as osteosarcoma, mast cell tumor, lymphoma, hemangiosarcoma of the spleen and heart was observed.

In these dogs, the increase in the incidence of these tumors was also related to early castration, in dogs under 6 months of age.

It is worth remembering that some breeds such as Poodle, Schnauzer, Yorkshire are breeds with a high predisposition to present breast tumors. So, for these breeds, castration may be indicated.

It is still not known for sure what the other function of sex hormones is and what interference of the absence of this sex hormones in dogs that leads the early appearance of tumors, cancers and even orthopedic diseases.

It favors the weight gain


Spayed dogs tend to be less energetic, so they reduce physical activity and play. But not all dogs are like that, some continue to show active behavior. Dogs that reduce physical activities can increase food consumption, thus increasing the dog’s weight gain.

Therefore, after castration, the use of food for castrated dogs is indicated, thus avoiding the animal’s weight gain associated with the reduction of physical activities.

Should I spay my female dog?

Even knowing the benefits of castration for the female dog, its harm must be considered. Tutors and veterinarians must agree on the animal’s general health status, tutor’s breeding intent, breed, age and location. Thus, the veterinarian can assist the tutor in the decision to spay or not the animals.

It is now known that some breeds are more predisposed to breast tumors, and these female dogs should be spayed. However, to the dogs that do not have a predisposition to breast tumors, other factors must be evaluated for the decision to castration to be taken.

Benefits of Castration

Even with the adverse effects, castration of female dogs has several benefits. Below we will talk about the main benefits of spaying female dogs.

Some benefits of female canine spaying:

  • Population control;
  • Prevention of some of tumors;
  • Prevention of pathologies of the reproductive system;
  • Prevents heat related problems.

Population control

Castrated dogs do not reproduce, thus helping with population control. Abandoned dogs can benefit more from this practice, while tutor dogs will never reproduce even if they are not castrated, requiring an evaluation with the veterinarian to make the best decision for the animal’s health.

Population control is very necessary due to the large number of abandoned dogs. Abandoned dogs without castration can generate many puppies and thus only exacerbate the problem by increasing the population of abandoned dogs. That’s why it’s important to perform castration, especially in abandoned dogs.

For tutor dogs, it is recommended to consult the veterinarian to assess the need for castration. If it is an animal that runs away a lot, it would be interesting to keep it castrated, avoiding problems with unwanted reproduction.

On the other hand, Molento and colleagues in 2007, show in their research that castration alone is not enough to help with population control. To be a real solution to the uncontrolled dog population problem, a mass castration must be associated with the education of the population for responsible dog care.

Prevention of some of tumors

In female dogs, spaying can reduce the chances of breast tumors. Some breeds, especially small breeds, are more predisposed to develop breast tumors. For these breeds, a consultation with a veterinarian for spaying is indicated.

Prevention of pathologies of the reproductive system

In female dogs, diseases such as pyometra, endometritis, uterine tumors, ovarian cysts and others are no longer a concern. In the surgery, the uterus and ovaries are removed, so the animal will not have any of these diseases.

Heat problems  

Female dogs in heat can release a bloody secretion, which can make the tutor’s house or apartment very dirty. During estrus, female dogs can also become more active and even try to run away to breed.  

Castrated female dogs, on the other hand, do not go into heat anymore, thus reducing the house dirt with bloody secretions. In addition to reducing the chances of runaways and unwanted compilations.


Castration is a surgical procedure that not only has benefits for dogs. The adverse effects of castration can affect the dog in a negative way, leading to the development of diseases and tumors. Therefore, the decision to castrate must be taken with the veterinarian who will evaluate the dog and present the positive and negative points of castration for each dog.

Frequently Asked Questions (FAQs): Side effects of spaying a dog

Spayed female dog comes into heat?

No, this is because castration removes the internal reproductive organs responsible for inducing heat. In this way, it is not possible for a castrated female dog to show heat. If the female dog is in heat a possible disease called remnant ovarian syndrome should be investigated.

Can a neutered dog still be attracted to an unneutered dog?

Yes, dogs can be attracted by the pheromones exhaled by unneutered dogs. But this does not indicate that there may be copulation between them.

What are the benefits of spaying a female dog?

The benefits of neutering a female dog are:

  • Population control;
  • Prevention of some of tumors;
  • Prevention of pathologies of the reproductive system;
  • Prevents heat related problems.


Beaver, B. V. (2001). Comportamento canino: um guia para veterinários. Roca.

de la Riva, G. T., Hart, B. L., Farver, T. B., Oberbauer, A. M., Messam, L. L. M., Willits, N., & Hart, L. A. (2013). Neutering dogs: effects on joint disorders and cancers in golden retrievers. PloS one, 8(2), e55937.

Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (2016). Neutering of German Shepherd Dogs: associated joint disorders, cancers and urinary incontinence. Veterinary Medicine and Science, 2(3), 191-19

McGreevy, P. D., Wilson, B., Starling, M. J., & Serpell, J. A. (2018). Behavioural risks in male dogs with minimal lifetime exposure to gonadal hormones may complicate population-control benefits of desexing. PLoS One, 13(5), e0196284.

McGuire, B. (2019). Effects of gonadectomy on scent-marking behavior of shelter dogs. Journal of Veterinary Behavior, 30, 16-24. 

Reichler, I. M. (2009). Gonadectomy in cats and dogs: a review of risks and benefits. Reproduction in Domestic Animals, 44, 29-35.

Starling, M., Fawcett, A., Wilson, B., Serpell, J., & McGreevy, P. (2019). Behavioural risks in female dogs with minimal lifetime exposure to gonadal hormones. PloS one, 14(12), e0223709.

UF College of Veterinary Medicine. (2015) The Visual Guide to Canine Reproduction. Available in:<>

Witsberger, T. H., Villamil, J. A., Schultz, L. G., Hahn, A. W., & Cook, J. L. (2008). Prevalence of and risk factors for hip dysplasia and cranial cruciate ligament deficiency in dogs. Journal of the American Veterinary Medical Association, 232(12), 1818-1824.

Picture from