Pet Sterilization: The Benefits & Risks of Spaying or Neutering Your Dog or Cat

Spay and Neuter are such buzzwords. You may have heard them from your vet, from your animal shelters, and even from your friendly neighborhood pet-parent. Having your pet spayed or neutered has now become a societal norm that is directly synonymous to responsible pet-parenting. But not all pet-parents are aware of how the process of spaying or neutering works, and the changes that it brings about in your pet.
 
In this article, we tell you all about Spaying, Neutering and Sterilizing your pet, the merits and risks of it and how you should go about deciding what you need to do.

Pet Sterilization and its Importance

Sterilization is usually a surgical process that involves the removal of certain reproductive organs in male and female dogs and cats. A sterilized pet cannot reproduce. This result of sterilization has led to its popularity as a way of controlling stray dog overpopulation. Like the ABC (Animal Birth Control) Programme by AWBI (Animal Welfare Board of India) that conducts mass-sterilization for strays. More on that below.
 

Sterilization of a Male Dog or Cat

Understanding the Male Reproductive Anatomy

In Male Dogs and Cats the structure of the reproductive system is made of Testicles, Vas Deferens, Prostate Gland, and the Penis. Sperm production and storage takes place in the Testicles. The Vas Deferens transport the sperms to the Prostate Gland. In the Prostate Gland, prostatic fluids nourish the sperms and it is transported to the Penis.

Neutering Male Dogs and Cats

Neutering involves the surgical removal of the Testicles. This removal ensures the male dog or cat can no longer reproduce. It also reduces breeding-instinct related behavior to an extent. Neutering is the most common way to get male pets sterilized. According to a study¹ by Dr. Laura J. Sanborn in 2007, neutering has its own merits and risks.
 

Benefits of Neutering your Male Dog

• Eliminates the risk of Testicular Cancer (Susceptible Breeds: Boxers, German Shepherds, Afghan Hound)
• Reduces the risk of non-cancerous Prostate Disorders
• Reduces the risk of Perianal Fistulas (Susceptible Breeds: Labradors, Bulldogs, Spaniels, German Shepherds)
• May reduce the risk of Diabetes (data inconclusive) (Susceptible Breeds: Miniature Poodles, Pugs, Dachshunds, Beagles)

Risks of Neutering your Male Dog

• Increases risk of Osteosarcoma (Bone Cancer) if done before 1 year of age (Susceptible Breeds: Saint Bernards, Great Danes, Doberman Pinschers, Rottweilers, German Shepherds, Boxers, Golden Retrievers)
• Increases risk of Cardiac Hemangiosarcoma (Susceptible Breeds: Golden Retrievers, German Shepherds, Boxers)
• Triples the risk of Hypothyroidism (Susceptible Breeds: Golden Retrievers, German Shepherds, Labradors, Dachshunds, Boxers, Cocker Spaniels, Dobermen, Rottweilers, Huskies, Dalmatians)
• Increases the risk of Progressive Geriatric Cognitive Impairment
• Triples the risk of Obesity (Susceptible Breeds: Pugs, Bulldogs, Beagles, Golden Retrievers, Dachshunds, Boxers, Rottweilers, Labradors)
• Increases risk of Prostate Cancer
• Doubles the risk of Urinary Tract Cancer (Susceptible Breeds: Beagles)
• Increases the risk of Orthopedic Disorders
• Increases the risk of adverse reactions to Vaccinations

The effects of neutering a male cat haven’t been studied much. Therefore, not much data is available to conclusively lay down the benefits and risks.
 

Alternatives to Neutering your Dog or Cat

Some of the demerits from Neutering occur because the removal of the testicles stops the production of testosterone. This causes an imbalance of hormones in the body.
 
Vasectomy is an alternate way of sterilizing your male dog or cat. Vasectomy involves the removal of only the Vas Deferens. This makes your male animal unable to reproduce since the vas deferens are what carry the sperms from the testicles. Vasectomy does not affect the production of hormones since the testicles are still intact. Therefore, it may not affect the breeding-instinct related behavior as in Neutering.
 

Sterilization of a Female Dog or Cat

Understanding the Female Reproductive Anatomy

Similar to human females, the reproductive system of Female Dogs and Cats is made of the Ovaries, Fallopian Tubes, Uterus, Cervix, and Vagina. Unfertilized eggs, and many hormones responsible for the heat cycle & maintenance of pregnancy are produced in the Ovaries. The unfertilized eggs pass from the Ovaries to Fallopian Tubes where fertilization takes place. The fertilized eggs are then transported to the Uterus where embryos mature.

Spaying Female Dogs and Cats

When you get your female dog or cat spayed, the ovaries, fallopian tubes, and uterus are removed surgically. Once spayed, your female dog or cat cannot reproduce, and her heat cycle stops. It also reduces breeding-instinct related behavior. Spaying is the most common way to get female dogs and cats sterilized. Some benefits and risks related to spaying were observed by Dr. Laura J. Sanborn in her 2007 study¹.
 

Benefits of Spaying your Female Dog

• Greatly reduces the risk of Mammary Cancer (the most common cancer in females) if done before 2.5 years of age
• Nearly eliminates the risk of Pyometra (which affects 23% of intact female dogs) (Susceptible Breeds: Rottweilers, Golden Retrievers, English Springer Spaniels)
• Reduces the risk of Perianal Fistulas (Susceptible Breeds: Labradors, BullDogs, Spaniels, German Shepherds)
• Eliminates the risk of Uterine, Cervical and Ovarian Tumors

Risks of Spaying your Female Dog

• Increases the risk of Osteosarcoma (Bone Cancer) if done before 1 year of age (Susceptible Breeds: Saint Bernards, Great Danes, Doberman Pinschers, Rottweilers, German Shepherds, Boxers, Golden Retrievers)
• Increases the risk of Splenic Hemangiosarcoma and Cardiac Hemangiosarcoma (Large Breeds are Susceptible)
• Triples the risk of Hypothyroidism (Susceptible Breeds: Golden Retrievers, German Shepherds, Labradors, Dachshunds, Boxers, Cocker Spaniels, Doberman Pinschers, Rottweilers, Huskies, Dalmatians)
• Increases the risk of Obesity (Susceptible Breeds: Pugs, Bulldogs, Beagles, Golden Retrievers, Dachshunds, Boxers, Rottweilers, Labradors)
• Causes Urinary ‘Spay Incontinence’ in 4-20% females
• Increases the risk of persistent or recurring Urinary Tract Infections
• Increases the risk of Recessed Vulva, Vaginal Dermatitis, and Vaginitis, especially for female dogs spayed before puberty
• Increases the risk of Orthopedic Disorders
• Increases the risk of adverse reactions to Vaccinations

Alternatives to Spaying your Dog or Cat

A lot of the risks associated with Spaying female dogs and cats are because the removal of the ovaries, fallopian tubes and uterus can cause an imbalance of hormones since the estrogen secreting ovaries are removed.
 
Hysterectomy is a type of sterilization wherein the uterus and part of fallopian tubes are removed. Sparing the ovaries allows secretion of hormones to still take place. This may not eliminate or reduce breeding-instinct related behavior, though.
 
Ovariectomy is another method where only the ovaries are removed making the animal infertile and eliminating their heat cycle and breeding-instinct related behavior.
 

Risks of Early Spaying or Neutering

Determining the time to get your pet spayed or neutered is extremely crucial. A lot of people promote getting the pet sterilized as early as possible, sometimes when they are as young as 6 weeks old. Some positives of early castration include rapid anesthetic recovery and fewer operative complications. However, many studies in recent years have proven that getting your pet castrated before they mature could be welcoming some serious trouble for the rest of their life.
 

 
According to a 2004 study² by Dr. C. Victor Spain, Dr. Janet M. Scarlett, and Dr. Katherine A. Houpt on the long-term risks and benefits of early-age gonadectomy (spaying or neutering) in dogs, following were the observations:
 

Abnormal Bone Growth

The growth plates of dogs and cats remain open until the animal reaches puberty. During this growth phase, estrogen and testosterone aid in the development of muscles and bones, until the growth plates are finally closed at puberty. If the hormone-producing glands are removed (as when spaying or neutering), these growth plates remain open allowing abnormal growth of bones. According to a 1995 study³ by Stubbs and Bloomberg, animals neutered/ spayed earlier were taller in comparison to those sterilized later or left intact.
 
Longer bones are not the issue per se. This abnormal bone growth paves the way for orthopedic injuries later in life and even increases the risk of Hip Dysplasia.
 

Urinary Incontinence

Urinary Incontinence is the condition where a trained dog loses control of his/her bladder. The severity of urinary incontinence could range from small leaks to large amounts of urine. In the study mentioned above, it was observed that early spaying of female dogs can lead to Urinary Incontinence also known as Spay Incontinence.
 
Other risks include an increase in Noise Phobias and even certain types of cancer.
 

Frequently Asked Questions & Common Myths about Sterilizing Your Pets

Does neutering or spaying my pet make him or her obese?

The procedure of neutering or spaying itself does not make your pet obese or gain weight. However, studies have proven some related factors. The loss of estrogens and androgens that occur due to castration cause a decreased metabolic rate, lowering the energy requirements (RER) of your pet⁴. Androgens and estrogens also stimulate general physical activity or roaming behavior in pets. Lack of activity in your pet, post-sterilization, will also reduce their energy requirements⁵.
 
Ensuring your pet does not gain excess weight post neutering or spaying will require you to make changes to their diet and the amount of calories they intake. You will also need to exercise them regularly. If these two are taken care of, obesity can be kept at bay even after neutering or spaying. Most sterilized pets are overfed and underexercised, leading to obesity.
 

Will neutering my male pet reduce his aggression?

Aggression is associated with Testosterone. Surgical removal of the testicles through neutering will stop the production of testosterone in the body, rendering your dog or cat less aggressive. However, while being one of the causes, not all aggression can be associated with testosterone. The only kind of aggression reduced by neutering is that associated with sexual instincts. Like fighting with other male dogs over a potential mate. Protective-possessive aggression may also reduce.
 
Note that neutering dogs does not change fear-based aggression. If your pet is afraid that someone or something may cause harm, he will act out aggressively even after being neutered.
 
It may become troublesome to house an intact male cat when a female cat around them goes under heat. They make act unreasonable and aggressive. Neutering can be considered in this situation to ease out the atmosphere.
 

Will spaying my female pet reduce her aggression?

While in males, the elimination of testosterone and the presence of estrogen and oxytocin induce calming and anti-anxiety effects, making them more docile in nature; the case with females is slightly more complex. Spaying will lead to surgical removal of your pet’s ovaries, where these hormones are produced. This will lead to a reduction or elimination of sexual-instinct based aggression. Like anger towards other bitches over a potential male mate while on heat.
 
However, the absence of the calming hormones will lead to an imbalance, with higher testosterone. Cases of already aggressive female pets becoming more aggressive after being spayed are noted in studies. Though there is no conclusive data to prove the results, it is believed that an increase in aggression can be expected.
 

Will neutering or spaying reduce the risk of cancer for my pet?

In the case of male dogs, neutering and hence the removal of the testicles eliminates the risk of Testicular Cancer. Testicular cancer is the most common cancer in intact older male dogs. It has a fairly noticeable prognosis and castration done in time is usually curative.
 
In female dogs, spaying before 2.5 years of age greatly reduces the risk of Mammary Tumors. Mammary tumors are extremely common, more so in intact dogs than spayed dogs. About 50% of these tumors are malignant in nature.
 
However, according to the same study¹ that observes the above positives, neutering and spaying also have some negatives in terms of cancer risks.
 
Neutering or Spaying increases the risk of:

• Osteosarcoma or Bone Cancer which is extremely common in medium to large breeds. It also has poor prognosis usually delaying treatment. Breeds like Saint Bernards, Great Danes, Dobermen, Rottweilers, German Shepherds, Boxers, Golden Retrievers are genetically predisposed to Osteosarcoma.
• Cardiac Hemangiosarcoma is the most common type of Cardiac Tumor in dogs. It is usually undiagnosed until complications arise. Medium to large dog breeds like Boxers, German Shepherds, Golden Retrievers are susceptible to it. Dogs older than six years are also likely to have Cardiac Hemangiosarcoma.
• Urinary Tract Cancers are rare. But they may occur in the kidney, bladder or urethra.
• The risk of Prostate Cancer goes up in male dogs. It is a rare but malignant type of cancer usually manifesting in older dogs between the ages of 9 to 10 years. Hormonal imbalance caused due to neutering is considered a reason for the increase in the risk of Prostate Cancer.

So, should one Neuter or Spay their Pet or Not?

After taking a holistic look at neutering and spaying, its advantages and risks, it is safe to say that a lot of this decision will be subjective to your dog and what you are trying to achieve. If a medical need demands of you to have your pet castrated, it may well be for their benefit to have them neutered or spayed.
 
Neutering your male dog, however, seems to have more risks than benefits. Hence, neutering to prevent future health problems may not be a compelling enough reason to have your pet neutered. For female dogs, the situation is more complex. The extent of the benefits of spaying surpass the risks (in some cases).
 

 
Overall, you need to take into consideration your pet’s breed and the health problems he/she is susceptible to. You also need to consider the right age to get them neutered. Anything before 6 months is inviting more trouble than good.
 
As for cats, early castration, as per the current state of studies⁶ does not seem to have any adverse effects.
 
While parenting a spayed/neutered pet comes with its challenges like controlling dietary habits, exercising the pet enough, etc. Parenting an intact pet isn’t a cakewalk either. It is very important that you know what you’re signing up for if you decide to keep your pet intact.

1. Know that there is absolutely nothing wrong in parenting an intact pet if it is for their benefit. It may go against societal norms, and you may have to answer a few nosy-aunties (pass them this blog). But as long as you know you are making the best choice for your pet, don’t let societal pressure force you into making a choice you do not want to make.
2. Have your pet trained by a professional trainer. Ensure they are always under your watch. Even when out on walks, have them on a leash at all times. Training your pet is crucial, especially when you decide to keep them intact. Your pet needs to learn to obey your commands to avoid potential mishaps.
3. Training can also help get rid of unwanted behavior like humping, urinary territory marking, uncalled aggression, etc.
4. Some kennels or pet-boardings may not agree to board an intact pet.

SEE ALSO: How to Find the Best Trainer for Your Pet

Being a responsible parent is important irrespective of the sterilization choice you make. Parenting an intact pet may need you still to be more cautious about their behavior. Always be on the lookout for anything unusual like lumps and bumps on the body. Obesity is the foundation of all health problems. Ensure that your pet gets a nutritious, balanced, species-appropriate diet in the right quantity. Exercise them enough, a little more than you think is enough. A tired dawgie is always a happy dawgie.
 

Animal Birth Control (ABC) Programme

Developed by the WHO and implemented by the Government of India

India has a very evident overpopulation of homeless or stray dogs. A lot of these dogs have in the past been killed by humans who see them as a nuisance. Spaying and Neutering proves a practical and humane solution to the situation, allowing the animal to live a full life while preventing societal harm. Spaying a single female dog can help prevent 67,000 births over six years.
 
To deal with the issue of stray overpopulation while avoiding the killing of animals, the GOI implemented the ABC programme. It also forbade the killing of street dogs mentioning that animals are not encroachers on the planet, and eliminating them is not a question. It called for all state functionaries such as municipalities to be obligated to carrying out the programme.
 

 
According to ABC, every stray dog must be sterilized (spayed or neutered), vaccinated and released in the exact location it was taken from. The sterilized animal also needs to have their ears clipped or tattooed to be identified as sterilized and immunized.

SEE ALSO: Animal Rights, Welfare & Safety Laws in India

Apart from reducing the numbers and maintaining the population, the ABC programme also helps eliminate the risk of Rabies, as all pets are to be given vaccinations along with the sterilization. Sterilized dogs also mean no fights between strays during the mating season. No aggression may mean reduced ill-treatment of dogs by residents, leading to a friendlier, harmless relationship between the dogs and humans.
 
Euthanization can only be carried out by a qualified veterinarian on animals that are diagnosed rabid, incurably ill or mortally wounded. They should be euthanized in a humane manner approved by the AWBI (Animal Welfare Board of India) and never in the presence of other animals.
 
A major role in overpopulation is played by breeders carrying out their processes unethically, handing out pets to irresponsible owners who later abandon the animal to the streets. As per ABC, every breeder needs to be registered with the AWBI. He/She must also maintain a record of all pups born/died from individual bitches. They must also ensure the person buying the puppy has the required knowledge for its upkeep, and keep a record of who they are selling the puppies to.