28 February 2023

Pros and cons of sterilising dogs and cats

  • Controlling the reproduction of pets helps to prevent diseases and it also, in many cases, prolongs the life expectancy of our dogs and cats.
  • Castration and sterilisation have advantages, but there are also risks.

Tuesday 28 February marked World Spay Day, an event that has taken place on the last Tuesday of February every year, since 1995. The objective of this day, promoted by the Human Society Veterinary Medical Association, is to raise awareness in society about the need to sterilise or castrate pets to control their reproduction and prolong their life expectancy.

At Dingonatura we would like to commemorate World Spay Day by analysing the benefits and the risks of these procedures for our furry friends.

Nowadays, sterilisation is a fundamental aspect in the health and quality of our pet’s life. Consequently, more and more professionals agree on the importance of educating the public in this regard so that society is aware of all the repercussions that exist through not controlling reproduction: unwanted litters, increased risk of certain diseases and behaviours that hinder coexistence that may lead to abandonment. So they advocate sterilisation and castration, always on biological and health grounds.

“It is helpful to clarify that even though both procedures serve to control reproduction, they are not the same thing. Castration refers to the removal of the genital glands (testicles in males and ovaries and uterus in females) and sterilisation refers to infertility, that is, eliminating reproductive capacity, either by cutting the sperm ducts in males or the oviducts in females. There is also the possibility of tubal ligation in females, which may be of interest if you want to avoid certain consequences associated with hormonal suppression,” says the head of Training and Technical Communication at Dingonatura, Lucía Santo Tomás.

Castration and sterilisation carry a number of health benefits and risks for pets that are important to consider. Both should be analysed on an individual basis depending on the specific case we are facing, and always guided by the advice of the veterinary professionals who are taking care of the health of our pets.

Benefits of castration and sterilisation

According to the conclusions of the sterilisation report from the Official College of Veterinarians in Malaga, the main advantages of castration are:

  • Avoiding unwanted pregnancies which help to control animal birth rates which, in turn, avoid the slaughter of young animals and encourage their responsible ownership. In the case of cats, controlling reproduction is an essential part of managing the feline overpopulation that exists in cities and towns, and it has important consequences for the cats (due to the spread of infectious diseases), for people (due to the increased risk of zoonosis resulting from a lack of adequate sanitary control in these colonies) and for the environment (as they are hunters that can generate an imbalance in the ecosystem).
  • Reducing the probability of mammary tumours which is one of the most common neoplasms in companion animals. According to data, up to 60% of mammary tumours in female dogs are malignant, while in the case of female cats, 90% of mammary tumours are considered malignant. It is shown that the sooner the female is castrated the less likely it is to develop but very early castration can have significant repercussions, such as chronic urinary incontinence.
  • Avoidance of testicular, vaginal, ovarian and uterine tumours in the case of castration.
  • Improving the control of diabetes. It is, therefore, advisable for diabetic females to be castrated in order to optimally control blood glucose levels.
  • Behavioural changes such as their breeding instinct, intrasexual competitive aggression (between animals of the same sex) and toward people or owners.
  • Lower risk of accidents and street fights as castrated animals that have access to the outdoors have a reduced need to defend their territory. Therefore, they have a lower risk of suffering certain infectious diseases acquired by scratches and bites from fights with other animals. Also, as their exploratory activity decreases, they are less likely to suffer from any accidents on the street.


By comparison, it is also important to take into account a number of disadvantages of sterilisation and castration for the health of our ‘furry ones’:

  • Increased risk of some types of cancer since oestrogen and progesterone play an important role in immunity. It is worth mentioning that castrated animals tend to live longer than those who are not, so they will have a higher probability of suffering tumours in old age. There are numerous types of tumours that can be suffered by pets (including bladder, prostate and bone carcinomas).
  • Urinary incontinence and persistent urinary infection. Some breeds, particularly those of a medium to large size, are more susceptible to suffer from this disease.
  • Increased probability of obesity. Sterilised animals eat more, have lower energy requirements (so they need fewer calories per day) and lower insulin sensitivity, so it is important to readjust their diet. In addition, their energy consumption decreases, since they have less interest in escaping to satisfy reproductive impulses or to explore and defend their territory, so we must also increase their daily activity.
  • Hypothyroidism. Animals ‘at large’ suffer less from immune thyroiditis (cause of hypothyroidism) as progesterone increases the production of thyroid hormones.
  • Behavioural problems. Aggressive behaviour after castration is more extreme in females who were aggressive before surgery, so other alternatives should be considered in these cases. Fears and phobias are also often intensified.
  • Vaccination reactions, surgical risks (although occurrence is very low) and impaired immune response.

Consequently, “controlling the reproduction of our pets involves a high degree of responsibility that falls on us. As their carer, we must assess the pros and cons in each specific case, taking into account the possible risks, both individual and collective,  involved in not doing it. In the case of opting to go ahead with it, it is advisable to assess both the procedure and the animal’s age, since both factors are crucial in minimising the risks associated with castration and / or sterilisation,” says Lucía Santo Tomás.