Sterilization of Dogs: At What Age Should It Be Considered, Depending on the Breed?

Nearly 1 in 3 dogs will develop a testicular tumor at some point in their lives. As a result, veterinarians often recommend early sterilization. Female dogs subjected to sterilization before their first, second, or third heat cycles have a 0.5%, 8%, and 26% risk, respectively, of developing mammary cancer. And until recently, the benefits of sterilization seemed unequivocal. But new studies are shaking up the established views and updating the recommendations. An update is needed.   Sterilization or castration of dogs—both male and female—within their first year has become routine in the United States and much of Europe. And it is being done earlier and earlier, sometimes before 6 months of age, without full awareness of the potential side effects. Sterilization obviously prevents the dog from reproducing, but it is often recommended for its effects on certain problematic behaviors (aggression, running away, urine marking, hypersexuality). It may also be recommended to prevent certain genital disorders (prostate infections, uterine infections) or tumors. A neutered dog is therefore more likely to live a long life and age more healthily. However, recent studies are challenging some of these claims. For certain dog breeds, sterilization may be associated with an increased risk of developing debilitating joint disorders (hip dysplasia, tear or rupture of the cranial cruciate ligament, and elbow dysplasia) or certain types of cancer (lymphoma, mast cell tumor, hemangiosarcoma, and osteosarcoma). However, overall, the data remain complex, inconsistent, and, above all, variable. But one thing is certain: the trends are not universal. Some cancers appear to occur less frequently after sterilization or neutering, while others occur more frequently. A genetic component appears to play a role, as evidenced by varying trends across breeds. A new study from the School of Veterinary Medicine in California aims to shed light on the subject by examining 35 different pedigree dogs and their susceptibility to developing joint disorders, cancers, or urinary incontinence depending on the age at which they were subject to sterilization. In most cases, the age at which a dog is subject to sterilization does not necessarily increase the risk of developing joint disorders and/or cancer. However, a notable difference across breeds has been highlighted. Smaller breeds appear to be at lower risk. Only the Boston Terrier and the Shih Tzu show a significant increase in cancer risk following sterilization. Based on this study, the following recommendations emerge, depending on the breeds studied:  

Australian Cattle Dog

In neutered males, there is no increased risk of joint disorders or cancer; sterilization can be performed at any age. In females, an increased risk of joint disorders after sterilization occurs only when the procedure is performed before 6 months of age. It is therefore recommended to perform sterilization on females after 6 months of age.

Australian Shepherd

In neutered males, there is no increased risk of joint problems or cancer; sterilization can be performed at any age. The recommendation is the same for females; however, a certain risk of cancer—particularly mammary cancer—may be associated with sterilization after 6 months of age or with not undergoing sterilization at all.

Beagle

In males, there may be an increased risk of joint problems if sterilization is performed between 6 and 11 months of age; researchers recommend postponing sterilization until after 1 year of age. In spayed females, there is no increased risk of joint problems or cancer; sterilization can be done at any age.  

Bernese Mountain Dog

Given the risk of joint problems in males, it is recommended to delay sterilization until well past 2 years of age. In spayed females, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age.  

Border Collie

Given the increased risk of developing certain cancers after sterilization, it is advisable to delay sterilization for both sexes until well past one year of age.  

Boston Terrier

In male dogs neutered before 11 months of age, a significant increase in the risk of cancer suggests that sterilization should be delayed until after 1 year of age. In female dogs, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age.  

Boxer

Given the increased risk of developing certain cancers following sterilization, it is recommended to delay the procedure for both sexes well beyond two years of age.  

Bulldog

In spayed females and neutered males, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age; however, caution is advised given the apparent risk of developing joint problems.  

Cavalier King Charles

In spayed females and neutered males, there is no increased risk of joint problems or cancer; sterilization can be performed at any age.  

Chihuahua

For females and neutered males, there is no increased risk of joint problems or cancer; sterilization can be performed at any age.  

Cocker Spaniel

It is recommended to perform sterilization on males after 6 months. Given the increased risk of cancer in females who are sterilized at 1 year of age, it is recommended to delay sterilization until after 2 years of age.  

Collie

In neutered males, there is no increased risk of joint problems or cancer; sterilization can be performed at any age. For females, given the apparent risks of cancer with sterilization before 6 months of age and urinary incontinence with sterilization between 6 and 11 months of age, it is advisable to delay sterilization until after 1 year of age.  

Pembroke and Cardigan Welsh Corgis 

For males, given the increased risk of intervertebral disc disorders when subjected to sterilization before 6 months of age, it is recommended to undergo sterilization after 6 months. For females, since there is no increased risk of joint disorders or cancer, sterilization can be performed at any age  

Dachshund

For females and neutered males, since there is no increased risk of joint disorders or cancers, sterilization can be performed at any age.  

Doberman

Based on limited data, it is recommended not to neuter males, or to do so before they are 1 year old to avoid the increased risk of cancer observed when sterilization is performed after 1 year of age. Also based on limited data, it is recommended to delay sterilization in females until after age 2 to avoid the risk of urinary incontinence and joint problems seen in females sterilized at an early age.  

English Springer Spaniel

In neutered males, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age. For females, given the increased risk of urinary incontinence in dogs sterilized before 1 year of age, it is recommended to delay sterilization until after 1 year of age.  

German Shepherd

For males, given the risk of joint problems, it is recommended to delay sterilization until after 2 years of age. For females, the same joint problems and the risk of urinary incontinence also make it advisable to delay sterilization until after 2 years of age.  

Golden Retriever

For males, given the risks of joint problems and cancer, it is recommended to delay sterilization until after 1 year of age. For females, given the increased risk of cancer following sterilization—regardless of age—it is recommended not to undergo sterilization, or to do so after 1 year while remaining vigilant.  

Great Dane

For females and neutered males, since there is no increased risk of joint problems or cancer, sterilization can be performed at any age. However, given their large body size and the delayed development of their musculoskeletal system, sterilization well past 1 year of age should be considered.  

Irish Wolfhound

Given the increased incidence of cancer associated with sterilization between 1 and 2 years of age in males, it is recommended to delay the procedure until after 2 years of age. In females, since there is no increased risk of joint disorders or cancers, sterilization can be performed at any age. However, given their large body size and the late development of their musculoskeletal system, sterilization well beyond 1 year of age should be considered.  

Jack Russell Terrier

For females and neutered males, since there is no increased risk of joint problems or cancer, sterilization can be performed at any age.  

Labrador Retriever

Given the joint problems that occur in males neutered before 6 months of age, it is recommended to undergo sterilization after 6 months. Given the joint problems that occur in females spayed before 11 months of age, it is recommended to undergo sterilization after 1 year.  

Maltese

For spayed females and neutered males, since there is no increased risk of joint problems or cancer, sterilization can be performed at any age.  

Miniature Schnauzer

For females and neutered males, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age.  

Miniature Spitz

For females and neutered males, there is no increased risk of joint problems or cancer; sterilization can be performed at any age.  

Toy Poodle

For females and neutered males, there is no increased risk of joint problems or cancer; sterilization can be performed at any age.  

Miniature Poodle

Given that sterilization has been associated with the development of joint problems, it is recommended to delay sterilization until after 1 year of age for males. For females, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age.  

Poodle

Given that sterilization at 1 year of age has been associated with the development of one or more types of cancer, it is recommended to delay sterilization until after 2 years of age for males. In females, since there is no increased risk of joint problems or cancer, sterilization can be performed at any age.  

Pug

For females and neutered males, since there is no increased risk of joint problems or cancer, sterilization can be performed at any age.  

Rottweiler

Given the occurrence of joint problems associated with sterilization between <6 and 11 months of age, it is recommended to delay sterilization until after 1 year of age for males. For females, given the increased risk of joint problems associated with sterilization before 6 months of age, it is recommended to delay sterilization until after 6 months.  

Saint Bernard

In neutered males, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age. For females, given the increased risk of joint problems with sterilization before 6 months of age, it is recommended to delay sterilization until after 6 months. However, given their large body size, sterilization well beyond 1 year of age should be considered.  

Shetland Sheepdog

In neutered males, since there is no increased risk of joint problems or cancer, sterilization can be performed at any age. However, to avoid the high incidence of urinary incontinence in females, it is advisable to perform sterilization on them after they are 2 years old.  

Shih Tzu

In neutered males, there is no increased risk of joint problems or cancer, so sterilization can be performed at any age. For females, however, there is an increased risk of cancer if sterilization is performed between 6 and 11 months of age, reaching up to 18% if done at 1 year of age. It is therefore recommended to delay sterilization for females until after they are 2 years old, or to perform sterilization 1 or 2 months before they reach 6 months of age.  

Westie

For females and neutered males, there is no increased risk of joint problems or cancer, so sterilization can be done at any age. However, for females, delaying sterilization until after one year of age may help prevent the risk of urinary incontinence.  

Yorkshire Terrier

For females and neutered males, there is no increased risk of joint problems or cancer, so sterilization can be done at any age.