Each year in the United States millions of homeless or unwanted dogs and cats are euthanized in animal shelters and humane societies. While precise numbers are difficult to obtain the estimates range from 3 to 4 million. Many factors have led to the overpopulation of dogs and cats and the solution will be multifaceted. Until safe and effective chemical or immunological sterilization is available spay neuter will be the cornerstone of any program to reduce the overpopulation thereby reducing the numbers of animals euthanized each year.

Pediatric neutering (ovariohysterectomy and castration) is supported by the AVMA and is becoming increasing popular especially in the shelter and high-quality high-volume spay neuter environments. The AVMA position statement says, "Resolved that the AVMA supports the concept of early (8-16 weeks) ovariohysterectomies/gonadectomies in dogs and cats, in an effort to stem the overpopulation problem in these species." "The concept is for the benefit of animal shelter and humane society spay/neuter programs. Individual veterinarians have the right/responsibility to decide on what age they will perform the procedure." Other organizations supporting pediatric neutering include the:
     • Canadian Veterinary Medical Association
     • British Small Animal Veterinary Association
     • European Society of Feline Medicine
     • Feline Advisory Bureau (U.K.)
     • Winn Feline Foundation

The most effective way to ensure that animals adopted from shelters do not reproduce is to spay or neuter them prior to adoption. Voucher programs or prepaid spay neuter programs in which arrangements to have an adopted animal spayed or castrated are made at the time of adoption simply do not work. Nationally compliance rate of these programs is less than 40%. With pre-adoption spay and castration there, obviously, is no compliance issue.

There are several advantages to pediatric neutering. In addition to the commonly accepted health benefits associated with ovariohysterectomy and castration, pediatric neutering offers additional advantages. It is an effective tool in dealing with the overpopulation of unwanted dogs and cats. The surgical procedures are easier, faster, and less expensive. The incidence of perioperative complications is low as the surgical procedures and, thus, the anesthetic episodes, are significantly shorter. Anesthetic recovery and healing time is shorter.

Historical Concerns

Historically veterinarians have expressed concerns about pediatric neutering. Their concerns have focused on either potential long-term physiologic effects or anesthetic risk. The adverse physiologic effects mentioned have been obesity, stunted growth, musculoskeletal disorders, perivulvar dermatitis, puppy vaginitis, feline lower urinary tract disease, and urinary incontinence and most fears appear to be unfounded.

Obesity is a multi-factorial problem with a tendency to occur regardless of the age an animal is spayed. A long-term study conducted at Cornell found a decrease in obesity for both male and female dogs that had undergone pediatric ovariohysterectomy.

Initial concerns that pediatric neutering may result in stunted growth have proven to be false. Removal of the hormonal influence actually results in a delayed closure of growth plates. The long bones of animals that undergo pediatric neutering are actually a little longer than those of animals neutered after 6 months of age. There is no clinical significance to the delayed physeal closure.

Some have questioned if early age spay neuter results in an increased incidence of hip dysplasia. Research on this has proven to be equivocal. A study at Texas A&M has shown no increase in hip dysplasia, while a study at Cornell showed a slight increase in incidence. Interestingly, the Cornell study also showed that dogs sterilized at a traditional age were 3 times more likely to be euthanized due to hip dysplasia. This suggests that if early-age gonadectomy increases the incidence of hip dysplasia it may be a less severe form.

Perivulvar dermatitis has been documented in unspayed and spayed animals regardless of the age at which the surgery was performed. This condition is related to obesity and age of neutering appears to have no significant influence on incidence.

There is no difference in the incidence of puppy vaginitis regardless of age of ovariohysterectomy.

Suspicion that pediatric castration would result in decreased diameter of the penile urethra in cats and, therefore, lead to urinary obstruction has proven to be unfounded. The diameter of the penile urethra in the adult male cat does not vary between animals neutered at 7 weeks or 7 months or from intact males.

Studies have shown differing conclusions with respect to estrogen responsive urinary incontinence. The Cornell study revealed a slightly greater risk of urinary incontinence in dogs spayed earlier than 12 weeks of age. The Texas A&M student showed no difference while a study by Arnold et al in 1992 showed a higher incidence of urinary incontinence in dogs spayed after their first estrus cycle.