Early spaying/neutering

A large part of a breeders job lies in the selection of future breeding animals. You want to set high standards for the quality of breeding animals both physically, mentally and in type to only bring the (seemingly) “best” genes forward. Meanwhile, there is the constant balancing act where we can not exclude too many animals from breeding because it would lead to a narrow breeding base – small genetic pool which could lead to undesirable effects such as inbreeding depression and disease.

Often it is only the phenotype we have to go on (what you can see on the outside) but more and more genetic tests are coming where you can find out the actual genotype (the genes the cat carries).

Anyway, when the breeder have had a litter, walked the tightrope and come to the decision which kittens are best for “only” wonderful pet cats this should be respected. The breeder is the one who has been with kittens since they were born, knows them, knows the pedigree etc.

Should you spay/neuter a cat that will not be used in breeding?

Overall, it is well documented that spayed/neutered cats live longer than uncastrated. One theory is that this is due to the reduced risk of gender-related diseases and behaviors. (1) An unspayed female cat comes in heat several times a year and this results in behavior that is annoying for both her and the owner. An unneutered male cat gets stressed by the smells of queens (even if they come from outside) and engage in behaviors such as urine marking and they can start eating less and therefore be lean etc. Below are some detailed examples of diseases and how they are affected by castration.

A study of 18,375 cats with cancer tumors from 1965 to 2008 shows that the risk of mammary tumors drops significantly for females who are spayed. (2) Of all cancers registered in cats 17% is mammary tumors. (1) This is therefore a large portion of the cancers of female cats. The risk of these tumors will decrease by 86% in females castrated before 1 year of age. (1) For other (less common) tumor / cancer types (such as gastrointestinal tumors, various skin tumors and cardiopulmonary tumors and others) the risk is minimaly higher in castrated cats. (2)

It goes without saying that even the risk of ovarian and uterine tumors disappear completely when these bodyparts are removed. As well as the risk of testicular tumors in males.

The risk of pyometra (uterine infection) in a study in Sweden is shown to be around 80 females per 10,000/year concerning Ragdoll, which of course is a relatively high number seen over the cat’s lifetime. Of these about 5.7% die from their infection (3). This risk is basically 0 after spaying. (1)

At five years old 50% of the unneutered males prove to have benign prostatic hyperplasia (BPH). This can in turn lead to prostatitis (infection of the prostate) and urinary tract infection. This is prevented by neutering. (1)

The risk of obesity and obesity-related diseases such as Diabetes mellitus increases for the spayed/neutered cats so you have to give them the right food and keep them in shape. (1)

Overall, basically all breeders and cat clubs agree that a cat should that is not going to be bred should be spayed/neutered.

The question now is when this is best done.

More and more breeders choose to Spay/neuter the kittens which is to be sold as pets before they move. Thus, before 12 weeks of age. The arguments for this include that they can not be bred further on, which is a benefit to the breed because the kitten is probably not “good enough” for breeding. That the new owner do not ignore spaying/neutering the cat in the future because it’s an expense that the buyer does not want to pay. That it is better for the new owner if it is already done when the cat is picked up as possible complications are managed by the more experienced breeder. The cats feel better by having it done and having it done early.

Some are also against early spaying/neutering and believe it is in different ways harmful to cats. Even many veterinarians seem in the current situation disinclined to perform eraly spaying/neutering.

What does science say about this?

In a clinical control study with 800 cats between 8-12 weeks of age where half were randomly assigned to direct spaying/neutering and half at 6-8 months of age, the two groups were compared, regarding the short-term and long-term health complications. The short term included the mortality (death) within 7 days of castration.

In the long term, the two groups were followed to 24 months regarding feline lower urinary tract disease (urinary problems), urethral obstruction (of males), lameness, fractures and hypersensitivity syndrome with dermatological (skin) presentation. Overall, no differences were found between the groups on either short-term or long-term health complications after spaying/neutering. (4)

In another study, it has been shown in the cat’s behavior a reduced risk of hyperactivity and aggression in cats spayed/neutered early (between 6-14 weeks of age). As for male cats a reduced risk of urin marking and other sexual behaviors have been shown compared to castration in the traditional age. A slightly increased risk of shyness, however, occurred in early spayed/neutered cats. (5)

It has also been seen a decreased risk of gingivitis (gum disease) and asthma in cats undergoing early castration. (5)

Another study regarding the anesthesia and the surgery in spaying/neutering in early age have shown that cats spayed/neutered early need less anesthetic drugs. The operation is done with minimal bleeding and recovery is rapid. No negative effects have been seen either short term or long term compared to spaying/neutering in the traditional age. (6)

An other study of anesthesia, which included 197 cats, of which half were spayed/neutered at an early age showed no mortality (no one died). (7)


I have searched through “PubMed” and “Web of Science”, which are two of the largest databases of scientific articles and I have read the latest thet is written within the area. Early castration seems to be defined a little different but between 6-14 weeks of age in the various articles. However hard I try I find no article where any significant negative effects are found regarding early spaying/neutering. Note that I have not bred any kittens of my own yet, and therefore I’am not predjudice in any direction. I just wanted to find out how the scientific foundation looks for early spaying/neutering today and this was the result.


  1. Reichler IM. Gonadectomy in cats and dogs: a review of risks and benefits. Reprod Domest Anim. 2009;44 Suppl 2:29-35.
  2. Graf R, Grüntzig K, Boo G, Hässig M, Axhausen KW, Fabrikant S, et al. Swiss Feline Cancer Registry 1965-2008: the Influence of Sex, Breed and Age on Tumour Types and Tumour Locations. J Comp Pathol. 2016;154(2-3):195-210.
  3. Hagman R, Ström Holst B, Möller L, Egenvall A. Incidence of pyometra in Swedish insured cats. Theriogenology. 2014;82(1):114-20.
  4. Porters N, Polis I, Moons CP, Van de Maele I, Ducatelle R, Goethals K, et al. Relationship between age at gonadectomy and health problems in kittens adopted from shelters. Vet Rec. 2015;176(22):572.
  5. Joyce A, Yates D. Help stop teenage pregnancy! Early-age neutering in cats. J Feline Med Surg. 2011;13(1):3-10.
  6. Kustritz MV. Early spay-neuter: clinical considerations. Clin Tech Small Anim Pract. 2002;17(3):124-8.
  7. Porters N, de Rooster H, Moons CP, Duchateau L, Goethals K, Bosmans T, et al. Prepubertal gonadectomy in cats: different injectable anaesthetic combinations and comparison with gonadectomy at traditional age. J Feline Med Surg. 2015;17(6):458-67