Millions of "excess" dogs and cats will be killed in shelters this year, while millions of homeless animals live short, hard, hungry lives on the streets, only to die miserably from disease, injury, or predation. About 1/3 of animals in shelters are purebreds, either intentionally or accidentally bred.

By being a responsible caregiver and sterilizing your companion animals, you avoid contributing to this terrible problem of pet overpopulation. Unsterilized (intact) dogs and cats usually find a way to get out and breed. Then, even if you could find good homes for the entire litter, each of your babies would displace another puppy or kitten that will then have to die.

Not all kittens and puppies taken to a shelter get adopted. If you take your litter to a typical, overcrowded shelter, it is likely that the entire litter of kittens or puppies will go straight from your hands to the killing room - they must be destroyed immediately, due to lack of cage space. (And don't think you can avoid the fatal consequences by taking them to a "no-kill" shelter - they may not have space. Even if they do accept your litter, that means other animals will be turned away, and taken to a shelter that may indeed kill them.)

Dogs and cats should be surgically sterilized to prevent unwanted pregnancies as well as undesirable mating-related characteristics and behaviors. In females, this operation is called "spaying" and involves removal of the ovaries and uterus through an abdominal incision. For males, "neutering" involves surgically removing the testicles. In most cases, your animal companion will be able to go home either the same day or the next day, and within a few days will be fully recovered. Young animals bounce back much quicker from these surgeries than older ones.

Neutered cats have a much lower risk of being infected by the deadly Feline Immunodeficiency Virus (FIV) (also called "Feline AIDS"), because they are much less likely to engage in fighting, which spreads this disease. Decreased roaming and territorial behavior in cats also lowers the risk of bite-wound abscesses. Neutering male cats stops spraying or urine marking in over 90% of cats, and solves this problems in female cats, who often will begin spraying when they go "into heat."

Spaying eliminates the "heat" cycle, which causes crying, pacing, and erratic behavior, especially in cats. Dogs in heat also produce a bloody vaginal discharge that can stain furniture and carpets. Cats and dogs in heat can attract persistent and often obnoxiously loud "suitors" from all over the neighborhood, even if they're kept indoors.

Spayed females are not susceptible to life-threatening uterine infections and reproductive tract cancers that can occur in breeding females, as well as mastitis, ovarian cysts, miscarriages and delivery complications. All these can be expensive to treat, and dangerous to your animal's health. Almost half of unspayed female dogs will develop breast cancer, while spaying before first heat reduces the incidence to almost zero. Even later spaying greatly reduces the risk. Spaying also decreases the risk of developing breast cancer in cats, for whom it is usually fatal.

Neutered male dogs are less apt to develop prostate cancer, and the risk of testicular cancers is eliminated. Up to 60% of older, intact dogs will get enlarged, painful prostates. Neutering male dogs greatly decreases the potential for aggressive behavior and biting, and tends to calm overactive dogs as well. It also decreases or eliminates "humping" behavior.

Some people think that their female dog or cat "should have at least one litter" before she is spayed, that it "settles" a dog or cat, or that she "needs" this experience to be a good household companion. This is completely untrue and there is no evidence, medical or factual, that supports this belief. Spayed and neutered dogs and cats are calmer, less frustrated, happier family members.

In the past, veterinarians recommended that a cat or dog be at least six months of age before they were sterilized. However, many cats and dogs reach sexual maturity before they are six months old, and many unplanned litters have resulted from this standard. Today, the American Veterinary Medical Association recommends "early spay/neuter," which is the sterilization of puppies and kittens between 8 and 16 weeks of age. This has proven to be very safe, with rapid recovery. Many shelters now require adopted animals to be spayed or neutered before they can go home. This policy has begun to make a noticeable difference in the number of unwanted litters, but overpopulation is still a very serious problem.

This is a completely unjustifiable excuse, as there are numerous videotapes available for children to watch if they are interested in seeing animals being born. There is no guarantee that the mother won't give birth in the middle of the night, or while the children are at school. To experience "the real thing," consider doing foster care for your local shelter. Foster homes willing to take pregnant or nursing animals are rare - they will be delighted to hear from you!

People often worry that sterilizing their dog or cat will cause obesity. It's true that spaying and neutering does change an animal's metabolism - more or less instantaneously - but it may take the animal several weeks to adjust its appetite "thermostat." A spayed or neutered animal requires fewer calories for maintenance than an intact one. Some experts recommend cutting the amount you feed by 1/4 to 1/3 for 4 to 6 weeks post-operatively. By doing this, chances are good that he or she will be able to self-regulate at that weight the rest of his or her life. Also, animals, just like people, need exercise and physical activity to maintain their ideal weight. We as caregivers are responsible for keeping our cats and dogs active. A companion animal's metabolism, just like that of humans, tends to slow down as we get older. Therefore, less food and more exercise may be appropriate for your cat or dog as he or she matures.

It is actually much cheaper in the long run to have your companion animal spayed or neutered. If your female does get pregnant, you would bear the cost of veterinary care, raising and placing the litter, and medical bills for the mother should pregnancy or delivery complications arise. For males especially, infections and fight wounds can take a bite out of your wallet. There are also all the other health risks for intact animals. In many communities, the law requires dogs and cats to be spayed or neutered unless a special license or breeder's permit is purchased. Annual license fees may also be significantly less if your animals are altered. Spaying and neutering are preventive measures that will save you money.

If the expense of the surgery is a problem for you, there are many low-cost spay and neuter clinics throughout the country, and many veterinarians offer discounts. Contact your local shelter or animal control agency for a referral.