Early spay Investigation results

Dr. Thomas J. Lane is an extension veterinarian at the University of Florida, College of Veterinary
Medicine (for equine, companion animals, and alligators). He has served as Executive Secretary of the
Florida Animal Control Association and a member of the AVMA Human-Animal Bond Committee. Dr. Lane has
researched the safety of early surgical neutering for years, and this lecture presented the facts which
support his opinion that spays and castrations are safe (have no negative effects) even at seven weeks of
age, with no statistical differences from spays and castrations at seven months of age.

Dr. Lane's talk began with a discussion of the realities of fertility in cats: two cats, producing eight
kittens per year, results in 800,000 cats in just eight years. Therefore, the earlier the intervention for
sterility, the better.

Dr. Lane mentioned non-surgical options: 1) Ovaban or 2) long-term use of GnRII. Both interventions require
responsible pet ownership because of the continued need to administer treatment. He compared these interventions
to 3) steroid-hormone suppression, and 4) chemical sterilants like the zinc derivatives (zinc gluconate
neutralized with arginine). Zinc derivatives so far have had inconsistent results and have been associated
with adverse painful tissue reaction from the injection into the testicular tissue. This makes the chemical
treatments like zinc unacceptable at this time. In addition, these nonsurgical methods rely very heavily on
per owner compliance (which is not dependable) or are unacceptably painful.

Early neutering can decrease hormone-dependent medical problems, as well as decreasing aggression, urine marking,
roaming and behavioral problems. Therefore, surgical sterilization is the method of choice.

Dr. Lane commented on the terminology used in reproductive research. "Neuter refers to both ovariohysterectomy
and castration, and should not be considered the same as castration alone. Since less than 60% of pet owners are
compliant with spay/castration contracts, Dr. Lane strongly prefers sterilization prior to adoption.

Prepubertal neutering is defined as neutering before the onset of fertility. For females this is between 4-21 months,
and for males this is between 7-10 months of age. Dr. Lane commented that many spays and castrations at six months
of age (the current veterinary practice) are often, therefore, already prepubertal. Dr. Lane promotes prepubertal
sterilization as early as six-seven weeks of age, with no evidence of any increased incidence of disease, nor
interference with the immune system. Specifically, the concern of stunted growth was addressed. Since the absence
of estrogen and testosterone delays closure of the growth plates, early gonadectomy actually results in larger
cats, not stunted growth.

Dr. Lane presented data from a study which included 31 kittens from seven litters. These kittens were divided into
three groups: Group 1 (neutered at seven weeks), Group 2 (neutered at seven months), and Group 3 (neutered at one year).
The specific concerns of this study were the urethral diameters and pressure, and the effects on behavior (activity,
playfulness, frequency of vocalization, excitement, aggression, and affection). Other measurements included physeal
closure (bone growth), body weight, and body fat. There were no differences in any parameter between Groups 1 and 2.
Therefore, the evidence supports the conclusion that veterinarians do not need to wait until six or seven months
of age to neuter (as is the current custom), when kittens can be safely neutered at seven weeks of age. Also noteworthy
is that the slight difference between Groups 1 & 2 compared to Group 3 equalizes with time (after the Group 3 cats were neutered).

Dr. Lane discussed the Alachua County Department of Animal Control. They have had an early neuter program since
September 1, 1990. So far 1,000-1,250 early neuters have been performed with no increases in morbidity nor mortality,
yet the number of animals euthanized has declined. Sixty-one humane societies from 24 states and five countries have been
identified as performing early neuters. In conclusion, Dr. Lane mentioned that he is collecting data on a long term study
which will take five years to complete. To date there has been no increased risk of urinary incontinence, nor anesthesia
problems, nor decreased bone strength, nor decreased immune response. Dr. Lane encouraged all breeders present to consider
early neutering of all pets, before delivery to the new pet owner, as the decisive step to prevent unwanted pregnancy and pet
overpopulation.

This study was funded in part by the American Veterinary Medical Association Foundation and The Winn Feline Foundation.