All our kittens are
spayed or neutered before going to their new homes. We feel that
they do much better if this operation is perform at a young age. We
also consider the fact that the new purchasers do not have to take
the risk of putting their new pet through an
By: Mark S. Bloomberg, DVM, MS; W.P. Stubbs, DVM; D.F. Senior, BVSc; Thomas J. Lane, BS, DVM; University of Florida at Gainesville. Funded by the Winn Feline Foundation, February 1991. Continuation funded Feb., 1992.
A progress report on
a study funded by The Winn Feline Foundation (truncated version)
The concept of early spaying and neutering
(e.g. before the animal is sexually mature) is not a new one. In the early
1900's, early neutering was the norm and it was not until much later that
questions were raised about the negative side effects of such a procedure.
Today most of the experts acknowledge that there has not been enough
scientific information available about the most appropriate age to neuter a pet. Until recently, there was no research data that either supported or disproved the idea that
neutering dogs and cats at ages younger than five to eight months was deleterious. There is, in fact, little scientific basis for selecting this age group as the most
appropriate time for neutering. Indeed, one investigator points out that many veterinarians have been practicing early neutering for years, since there is an incredible
range of ages when puppies and kittens reach sexual maturity. Large animal practitioners have long practiced early neutering on their livestock and consider it not
only acceptable, but desirable in many cases. Even before concerns for the burgeoning population of unwanted pets raised our collective consciousness, there were many
scientifically documented reasons to spay and castrate. Spayed females are protected against mammary cancer and uterine infections. In males, castration reduces the risk of testicular cancer and enlargement of the prostate and related infections. From the pet owners point of view, the spayed or castrated pet is a much better companion. They are less aggressive and more affectionate than their unaltered counterparts. Since they are not driven by the urge to reproduce, they are less likely to roam and fight. Controlled studies into the short- and long-term effects of early neutering have been sadly lacking until recently. While there had been numerous anecdotal reports of early spaying and neutering, these cases were generally uncontrolled from the scientific viewpoint. Most reported cases were random bred, unrelated animals from a variety of backgrounds and no attempt was made to control for these variations. There have been few university based studies in this area. M.A. Herron of Texas A&M reported in 1972 that neutering before sexual maturity had relatively little effect on the diameter of the urethra in male cats. Studies have more recently been conducted at Angell Memorial Hospital in Boston, the College of Veterinary Medicine at the University of Minnesota, and the Department of Small Animal Clinical Sciences at the University of Florida. The Florida project, begun in 1991 and completed in 1992, was funded by the Winn Feline Foundation in conjunction with the American Veterinary Medical Association (AVMA). A serious attempt was made in this study to limit background influences and genetic variation. The kittens were bred especially for the project and litter mates were divided among the three groups. The queens were bred and housed in quarantined facilities since both pre- and post-natal nutrition and other factors can contribute to the ultimate size, weight, and overall health of the kittens. Dr. Mark Bloomberg indicates that although long-term follow-up results are incomplete, the initial results are extremely positive. Prior to undertaking the Winn Foundation study, Dr. Bloomberg had completed a similar study in dogs. Animals involved in that study have now been followed for over five years, with no negative side effects reported. In the Winn Foundation study, there were a total of 31 domestic shorthair kittens from 7 litters born on the Gainesville campus.
The kittens were divided into three groups:
Group 1 (11 kittens) were neutered or spayed at 7 weeks of age. Group 2 (11 kittens) were neutered or spayed at 7 months. Group 3 (the control group of 9 kittens) were not neutered until maturity and after the completion of the first phase of the study at 12 months.
The results of this study so far indicate that the differences between cats neutered at 7 weeks and 7 months are insignificant. The differences observed between animals in
Groups 1 and 2 and the animals in Group 3, while in some cases statistically significant, are not differences which appear to affect the health of the animal in a
negative way. While the final results will depend on the analysis of long-term follow-up, the indications are that early neutering is not detrimental to the health of the animal.
From the perspective of shelters and particularly in respect to the problem of surplus puppies and kittens these results are encouraging. If all the animals adopted
from shelters, including puppies and kittens, are neutered prior to adoption, there should be a corresponding decrease in the numbers of animals euthanized each year
in this country. Preliminary results from Alachua County, near the University of Florida at Gainesville, would seem to support this theory.
Alachua County Animal Control has been working with the investigators at the University and have had an early neuter policy in place since 1990. No animal leaves the shelter without being neutered. In 1987 the county euthanized 1,250 cats and dogs per month. Since implementing the early neuter policies they have seen the numbers drop to 940 per month in 1992 and there has been no increase in morbidity or mortality associated with the program.
In the last year, recognition of the safety and efficacy of early spay/neuter has grown rapidly. The American Humane Association has endorsed early neutering prior to
adoption as a "feasible solution to decreasing pet overpopulation and the tragedy of resulting deaths." In July 1993, delegates to the American Veterinary Medical
Association Annual Meeting voted to give AVMA's support to the concept of early neutering. Work done by veterinarians at Angell Memorial Hospital for the
Massachusetts Society for the Prevention of Cruelty to Animals supports Dr. Bloomberg's observations. Other organizations involved in early neuter programs include
the Denver Dumb Friends League in Colorado, the Miami Humane Society and Alachua County Animal Control in Florida, The Humane Society of Austin and Travis County in Texas, the Chicago Animal Control in Illinois, the King County Animal Control in Washington state, the Vancouver SPCA in British Columbia and the Southern Oregon
Humane Society in Oregon. The Dekalb Humane Society in Decatur, Collie Rescue of Metro Atlanta, the Georgia Alliance of Purebred Canine Rescuers, The Haven (dog
rescue) and Dog River Sanctuary in Douglasville are among the Georgia organizations working with early neuter in dogs and cats, as well as exotic species.
The Cat Fanciers' Association (CFA) has changed its show rules to permit altered kittens to compete. Many breeders of pedigreed cats are working with their veterinarians
to neuter pet quality kittens prior to placement in new homes. Those breeders who have adopted this policy report that they are very happy with the practice. New pet owners indicate that acquiring an already neutered animal relieves them of the worry and expense of scheduling the surgery at a later date, enabling them to relax and enjoy their new companion. As is the case for shelter managers, breeders can relax in the knowledge that the kitten they place today is not going to contribute to the surplus pet population tomorrow.