The “Fix by Five” Initiative: Feline Spay/Neuter by 5 Months of Age Becomes the Accepted Norm

Spaying or neutering cats before five months of age will reduce the incidence of unplanned pregnancies and the birth of unwanted litters of kittens.

by Philip A. Bushby, DVM, MS, DACVS

In an era when some in the profession are raising questions about the appropriate age to spay or neuter dogs, it is becoming apparent that there is little or no controversy about the age for these surgeries in cats. And the appropriate age is no longer considered six months or older. Spaying and neutering cats before five months of age has become the accepted norm, thanks in part to the “Fix Felines by Five” Initiative.

Veterinary Task Force on Feline Sterilization

In 2016, a task force was established to review the evidence and make recommendations on the optimal age for ovariohysterectomy and castration of cats. A meeting of the task force in January 2016 resulted in a position paper documenting the reasons why veterinarians should reduce the age at which they recommend sterilization of cats.

• Unlike in some breeds of dogs, there is no evidence that spay or neuter of cats before sexual maturity results in any adverse behavioral, orthopedic, neoplastic, or medical conditions.
• Cats can become sexually mature by five months of age. Female cats can become pregnant by five months of age. Spaying or neutering cats before five months of age will reduce the incidence of unplanned pregnancies and the birth of unwanted litters of kittens.
• Mammary neoplasia is the third most common neoplasia in cats, and most mammary tumors in cats are malignant. The average life expectancy of cats diagnosed with mammary neoplasia is less than one year. Sterilization of female cats before five months of age significantly reduces the incidence of mammary neoplasia.
• Sexual behaviors (spraying, roaming, fighting in males, and signs of estrus, pregnancy, and birth of unwanted kittens in females) are often the reason that cats are relinquished to animal shelters. Castration of male cats before five months of age significantly reduces male sexual behaviors, and ovariohysterectomy of female cats eliminates estrus, pregnancy, and the birth of unwanted kittens.

The task force’s final recommendation states, “Given the known benefits of sterilization and the lack of evidence for harm related to age at which the procedure is performed, the Veterinary Taskforce on Feline Sterilization calls for veterinary practitioners and professional associations to recommend sterilization of cats by five months of age.”

Since the release of the task force’s position paper, AAHA, the AVMA, the American Association of Feline Practitioners, the Association of Shelter Veterinarians, the CATalyst Council, the EveryCat Health Foundation (formerly the Winn Feline Foundation), the Cat Fanciers’ Association, the International Cat Association, PetSmart Charities, and 13 state veterinary associations have all endorsed the concept of spaying or neutering cats before five months of age.

Quicker, Easier, Safer

Experienced spay/neuter surgeons recognize that ovariohysterectomy and castration are easier, safer, and quicker in cats younger than five months of age than in cats six months or older. Recovery from anesthesia and surgery is also faster in the younger cats. The veterinary literature documents no difference in the incidence of major complications and a reduced incidence of minor complications following spay or neuter of cats younger than five months of age.

Resistance

In spite of overwhelming evidence and the endorsement by major veterinary professional associations, feline associations, and several state veterinary associations, some in the profession have been reluctant to adopt this new norm. Reasons for resistance to change include never having been taught the surgical procedures in cats that young, concerns about safety of anesthesia in younger kittens, and fear of urinary obstruction in male cats castrated before sexual maturity.

Let’s put to rest each of those concerns.

The Surgical Procedures

Ovariohysterectomy and castration of cats under five months of age are performed in a manner identical to those surgeries in older cats. Obviously, the patients are smaller, but the surgeries are faster and easier; there is less fat and less potential for hemorrhage. For those unfamiliar with the surgeries in cats under five months of age, surgical videos are available online. (See online bonus content on trends.aaha.org.)

Anesthesia

Many anesthetic drugs available now are perfectly safe in cats as young as six to eight weeks of age and are certainly safe in cats four to five months of age. Many high-quality, high-volume spay-neuter programs utilize total intramuscular anesthesia protocols and find that they provide surgical-plan-level anesthesia for the duration of the surgeries. With anesthetic reversal after surgery, cats can be fully recovered from anesthesia within 30 to 45 minutes.

Urinary Obstruction

There appears to be a long-standing myth that castration of male cats before sexually maturity predisposes the cats to urinary obstruction. The thought is that the younger the cat is castrated, the smaller the penis when the cat reaches adulthood and, therefore, the smaller the diameter of the urethra. There is, however, no evidence in the veterinary literature of an increased incidence of urinary obstruction in cats castrated under five months of age. In fact, the veterinary literature documents that urethral diameters are the same in cats castrated at seven weeks of age, cats castrated at seven months of age, and cats left intact.

Implementation and the Path Forward

For those veterinarians who have not yet made the change to spay or neuter cats before five months of age, the implementation is easy. Simply adjust your routine kitten wellness protocol by adding one more appointment two to three weeks following the last routine vaccination appointment. This additional appointment would be for ovariohysterectomy or castration and would result in the surgery being performed between four and five months of age.

In a shelter environment, spay or neuter can be safely performed as young as eight weeks of age.

If all small-animal veterinarians adopted the practice of spaying or neutering cats before five months of age, the number of births of unwanted litters of kittens would be significantly reduced. This would reduce or eliminate the influx of kittens who are relinquished to animal shelters in the spring (“kitten season”). The incidence of mammary neoplasia in adult female cats would be reduced, and the relinquishment of adult cats for sexual behaviors would also be reduced. 

References

AAHA Position Statements and Endorsements.

Veterinary Task Force on Feline Sterilization. 2016. “Recommendations for Age of Spay and Neuter Surgery.”

Philip A. Bushby, DVM, MS, DACVS, a 1972 graduate of the University of Illinois College of Veterinary Medicine, is a board-certified surgeon and has served on the Mississippi State University College of Veterinary Medicine (MSU-CVM) faculty for 42 years. He established the MSU-CVM shelter program and is a frequent speaker on efficient spay/neuter. He holds the Marcia Lane Endowed Chair of Humane Ethics and Animal Welfare at Mississippi State University.

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