The Nanaimo SPCA has done pediatric spay/neuter surgery for years. Weight seems to be a major criteria. Veterinarians will not operate on animals under a certain weight. Usually eight weeks is quite safe. No animals are released from Nanaimo until they are fixed. Foster parents frequently care for young kittens until they are old enough to withstand surgery.
Leaving this surgery until an animal is mature can be a dangerous proposition. One of my cats, an older-ex-feral, who was about seven years old when we took her home, has just been diagnosed with mammary cancer. She was spayed by the Nanaimo SPCA when she was about seven years old. That was over four years ago. This health problem seems confined to cats who are spayed when they are adult. Pediatric spay/neuter eliminates this very serious problem and many other problems as well.
Pediatric spay/neuter has been shown to be safe and effective for both cats and dogs. Here is a comment from Auburn Veterinary School on the subject. There is no reason that this relatively simple surgery should not be performed.
http://www.auburn.edu/~simslni/sheltermedicine/pediatricspayneuter.html#notes
Euthanasia of healthy unwanted cats and dogs remains the leading cause of death of these species. The Humane Society of the United States estimates that 4-6 million are euthanized annually in this country alone. This number has decreased markedly since the 1980's when an estimated 17 million cats and dogs were killed annually in the United States. Awareness of the magnitude of the problem, humane education and promotion of surgical sterilization are responsible for this dramatic decrease. The pet overpopulation problem, however, is far from being solved. In addition, the dynamics of the problem are changing, with cats currently outnumbering dogs entering many shelters in the U. S.
Pet owner surveys reveal that the leading source of pets entering shelters are unwanted litters. Although virtually all animal shelters require adopted pets to be sterilized, the compliance rate of owners according to the American Humane Association is only approximately 50% on a national basis, despite implementation of spay/neuter contracts, coupons, other incentives and time-consuming follow-up. For these reasons, the American Veterinary Medical Association advises that all pets be neutered before adoption, including puppies and kittens as young as 8 weeks of age.
The ideal age to spay/neuter dogs and cats is unknown. Currently, the most common age or the "traditional age" for recommending spaying/neutering is 6 months. This recommendation, however, is not based on research indicating that this is the ideal age to perform these procedures, but was probably chosen because anesthetic and surgical techniques were less advanced at the time and surgical success was more likely in a larger patient.
Approximately 30 years ago, humane organizations began sterilizing young puppies and kittens. Understandably, many veterinarians expressed concerns and questions regarding the short- and long-term safety of sterilizing pediatric patients. In response to these concerns, numerous controlled prospective studies and retrospective cohort studies have been performed to verify the safety of early age spay/neuter. Based on these studies, we can now conclude that sterilizing young puppies and kittens is a medically-sound practice, and is not associated with any serious medical or behavioral risks. In addition, early age spay/neuter offers many advantages including well-established, safe anesthetic and surgical techniques, shorter surgical and recovery times, and avoidance of the stresses and costs associated with spaying while in heat, pregnant or with pyometra. There are also numerous long-term health benefits including virtual elimination of the risk of mammary and testicular tumors. Finally, in addition to benefiting the individual patient, early age spay/neuter helps veterinarians to fight the single largest killer of dogs and cats: overpopulation and euthanasia of unwanted, homeless pets.
Jean Martin