Pet Spaying and Neutering of Dogs and Cats

Early Spays & Neuters

In the United States, most dogs and cats are spayed/neutered between 5 and 8 months of age. To try to control pet overpopulation, many humane shelters have started to spay/neuter all animals before they are adopted. This means they are spaying/neutering animals at a younger age, even 6-14 weeks of age. Many veterinarians in private practice have started early spaying/neutering as well.

Questions have arisen regarding the safety of this procedure and possible effects on the animals when they become older. However, as more studies have been done, and veterinarians have followed early spayed/neutered animals into older age, these concerns have been shown to be unfounded. Studies in which three groups of dogs were spayed or neutered at different ages showed no significant differences in growth rate, food intake, or weight gain in the three groups of dogs.

Early spaying/neutering has been shown to be safe in multiple studies. It must be remembered that younger animals may need different anesthetics and are more prone to hypothermia (lower than normal body temperature) during surgery. But as long as procedures are modified to account for these differences, early spaying/neutering is very safe. In fact, animals spayed/neutered at a younger age, often have faster recoveries than those spayed/neutered when they are older.

Myths about Spaying & Neutering

Spaying and neutering does change the metabolism of companion animals, so in most cases, they do not need as much food to maintain their weight as unspayed/unneutered dogs. The problem is not with the dog - it is us. We just tend to overfeed our dogs, and neutered/spayed dogs are more apt to put on weight because of that.

As for laziness, again, the amount of exercise our dogs receive and their activity levels are often dependent on us. If we do not give them opportunities for play and exercise, they can become couch potatoes just like some people. Many spayed/neutered dogs hunt, are entered in agility shows, become service dogs, and are trained in search and rescue. These dogs are anything but lazy.

Early spaying/neutering has been shown to be safe in multiple studies. It must be remembered that younger animals may need different anesthetics and are more prone to hypothermia (lower than normal body temperature) during surgery. But as long as procedures are modified to account for these differences, early neutering is very safe. In fact, puppies neutered at a younger age often have faster recoveries than those neutered when they are older.

We recommend that dogs be spayed before they have a heat. There are several reasons for this:

• Spaying a dog before her first heat is the best way to significantly reduce the chance your dog will develop breast cancer, a common condition in female dogs. The risk of malignant mammary tumors in dogs spayed prior to their first heat is 0.05%. It is 8% for dog spayed after one heat, and 26% in dogs spayed after their second heat.
• Any heat brings with it a chance your dog could become pregnant. This would adversely affect the health of a young dog.
• A heat also brings with it the chance for accidents. Dogs in heat have been known to run through glass patio doors, jump out of moving cars, and be hit by cars as they attempt to find a mate.
• Owners of females in heat also frequently have to deal with a sudden influx of male dogs around the home and yard. These amorous visitors leave numerous droppings, and spray plants and trees with urine in an attempt to mark their new found territory. There is also the mess and hassle of vaginal bleeding that typically goes on for 7 to 14 days. Who wants to deal with that if they do not have to?

Neutering - Why it's a Good Idea

Other than population control, there are lots of very, very good reasons to castrate (remove the testicles from) male dogs. They basically fall into one of two categories – they are either behavioral or medical. Regardless of which category we are talking about, most of the unwanted characteristics or conditions are caused by the male hormone testosterone, which is produced within the testicle. That is the major reason vasectomies have never been that popular in veterinary medicine. A vasectomy eliminates successful breeding, but it does not reduce any of the undesirable problems of the intact male, since it does affect testosterone production or its distribution throughout the rest of the dog's body.

Behavioral advantages of neutering

Decreased Aggression: One of the most important behavioral advantages of castration is that as adults, these dogs will tend to be less aggressive both toward other male dogs and also people. The androgen (male) hormones, of which testosterone is the most important, are responsible for the development of many behavioral patterns. When young puppies are sexually mounting their 7 and 8-week old litter mates this is because of androgen surges in their bodies. The same is true with aggressive behavior. Some medications that have androgenic hormonal activity often cause increased aggression (an example would be the birth control medication, Cheque Drops, which contains one of these androgen-type chemicals). The degree castration has on suppressing aggression varies between animals and the age at which it is done. Its effect is greatest if it is done before one year of age.

Decreased Roaming: A second behavioral advantage of neutering is that these dogs will not 'roam' when they sense a female in heat. Male dogs can sense females in heat through pheromones. These are airborne chemical attractants that are liberated from the female when she is cycling. They travel through the air for great distances. We grew up on a farm where the next closest house was over a mile away, but when one of our female dogs was in heat, the males would come for miles from upwind, downwind, and crosswind. Pheromones are, to say the least, very effective stimuli. In the seventies, it was briefly popular to do vasectomies on dogs thinking that we would not be taking the 'joy of sex' away from our canine counterparts. The problem with this reasoning was that many of us keep our dogs restricted in our homes, a kennel, or on a chain. Now think of the psychological stress the vasectomized male is under when he is locked up, but yet smells that female in heat four blocks away. There is no joy of sex, as he is trapped on your property unable to go and mate with her. He is, in effect, teased continuously for three to fourteen days while the female is in estrus and he is unable to mate with her. If dogs are neutered at an early age, they will not sense or respond to pheromones, and would certainly be less stressed and tend to stay home.

Increased Concentration: A third behavioral advantage occurs when you are training or working your dog, or using him for field work. If neutered, he will be a much better student with a much longer attention span when there are females nearby that are in heat. This is because he will not be constantly distracted by pheromonal stimuli.

Medical advantages

The medical advantages are numerous and even more significant. Again, all are caused by the effects of testosterone on the body or are physical problems that arise within the testicles themselves. Here again, a vasectomy would not serve any real or meaningful purpose.

No Testicular Tumors: There are several different tumor types, both benign and malignant, that arise within the testicles. As with most cancers, these usually are not noted until the animal reaches 5 or more years of age. Therefore, these would not be a problem in those individuals castrated at the recommended age.

Improved Genetics: We all agree that a male carrying a harmful genetic trait like hip dysplasia or epilepsy should be neutered. We must do all that is possible to prevent the spread or continuation of these conditions and others like them.

Fewer Hernias: A hernia is a protrusion of an organ or parts of an organ or other structure through the wall of a cavity that normally contains it. Perianal hernias occur when the colon, urinary bladder, prostate, or fat protrude from the abdominal cavity, through the muscular wall by the anus and then lie just under the skin. This type of hernia is far more common in older, unneutered male dogs. The levels of testosterone and other hormones appear to relax or weaken the group of muscles near the anus. When the animal then strains to defecate or urinate, the weakened muscles break down and the abdominal organs and fat bulge out under the skin. In shorthaired breeds, this large bulge is noted by the owner almost immediately, but in the longhaired dogs, the problem may go on for months before anyone realizes there is an abnormality. Left untreated, these organs may become damaged, unable to function or even die from loss of blood supply. Additionally, because of the displacement of organs into this area, the animal may not be able to defecate or urinate correctly or completely and may become constipated or have urinary incontinence (dribble urine). The surgery to repair this condition is not simple and today can easily cost $700 to $1500 or more, depending on the severity.

Fewer Perianal Tumors: There are tumors whose growth is stimulated by testosterone. These occur near the anus and are called perianal adenomas (benign) or perianal adenocarcinomas (malignant). As with the hernias, these usually do not occur until the dog is at least 7-years old. They require surgical treatment and should be caught early in their development to prevent recurrence. These tumors and the above hernia are very, very rare in those individuals castrated at 7 to 8-months of age.

Fewer Prostate Problems: The most common medical problems eliminated in dogs neutered at an early age are those involving the prostate. Over 80% of all unneutered male dogs develop prostate disease. Prostate conditions such as benign enlargement, cysts, and infection are all related to the presence of testosterone.

Early neutering

In the United States, most dogs are neutered between 5 and 8 months of age. Many humane shelters and veterinarians are starting to neuter male animals at a younger age, even 6-14 weeks of age. This early neutering does not affect the growth rate, and there are no appreciable differences in skeletal, physical, or behavioral development between those animals neutered early than those neutered at a more traditional age. It must be remembered that younger animals may need different anesthetics and are more prone to hypothermia (lower than normal body temperature) during surgery. As long as procedures are modified to account for these differences, early neutering is very safe. In fact, animals neutered at a younger age often have faster recoveries than those neutered when they are older.

Summary

None of the behavioral or medical problems caused by testosterone are rare. Veterinarians deal with them on a daily basis. To say it in a way that may not sound very nice but is certainly true – veterinarians would make a lot less money if everyone neutered their male dogs before they were a year of age.

Pet Population Control

Absolutely! In the United States alone, more than 50,000 puppies and kittens are born each day. For every pet with a place he can happily call home, there are 4 companion animals who are homeless, neglected, or abused. Millions of these animals enter America's animal shelters and 30 to 60 percent of them have to be destroyed each year because no one wants them - that is 4 to 6 million animals!

What can I do?

• Spay and neuter your dog(s).

• Encourage leash laws, which will help keep dogs safe and either at home or with their families.

• Educate others about this pet overpopulation problem. People who know the facts can make the right decisions.

• Express your thanks to veterinarians who reduce their spay/neuter fees and work with their local shelters to assure only neutered or spayed animals are placed.

Making sure you have homes for all the puppies is a good first step. You also need to be sure the breeding will produce quality puppies. Have the male and female dogs had a medical exam to be sure they are healthy? Are they free of venereal diseases? Are they free from hereditary problems such as hip dysplasia in dogs? Are their vaccinations up-to-date, and have they been wormed? Do you know what food and equipment you will need to give the mother and puppies proper care? Are you ready to pay the extra veterinary costs if there are problems with the pregnancy or delivery? You see, a lot goes into responsible breeding.

Spaying Lactating Dogs or Cats

Q. Is it okay to have my pet spayed if she is still lactating?

A. Spaying a lactating (producing milk) female is generally not recommended. Even if the puppies or kittens are weaned, the mother may still be producing a small amount of milk. In most circumstances, veterinarians will wait to spay the mother until she has stopped milk production (usually about 2 weeks after the young are weaned). If a female is spayed while still lactating, the incision in the abdomen may cut into some of the mammary tissue, resulting in milk flowing into the incision site. This can interfere with visualizing the internal organs and may complicate the healing process. In addition, there may be additional bleeding because of the larger blood vessels in the area of a milk producing gland.

Spaying - Why it's a Good Idea

Newspapers, radio, and television commonly feature articles about pet overpopulation. They stress the fact that too many puppies and kittens are produced every year and that there just are not enough potential owners to go around. The obvious conclusion is that we should breed fewer dogs and cats and produce fewer litters. The best way to ensure that this occurs is through sterilization procedures, so a larger percentage of dogs and cats are incapable of breeding. Performing an ovariohysterectomy (spaying) female animals is the best approach to decreasing the number of puppies and kittens. Being veterinarians, we also know that spaying and castrating pets are important to the average pet owner because of the health and well being of their animals. So, although you may spay your animals in an effort to help control a national problem, in doing so, you increase their chances of living long healthy lives.

Having a litter of puppies may seem like a fun thing to do. Some even believe that it helps their female dog, in some way, to develop more completely or become a better pet. Neither is true. Becoming pregnant and having a litter of puppies in no way alters the maturity level of the dog, either physically or mentally. In most cases, people find out that it is hard to find good homes for all of the puppies, regardless of the selling price. In addition, not all pregnancies go smoothly. Difficult labor, puppy mortality, and potential health problems in the mother, such as uterine and mammary gland infections, can take all the fun out of the experience. Most of the clients we have worked with end up wishing they would never have allowed their female to have a litter. Professional breeders are prepared and equipped for the entire process and it should generally be left to them.

The female reproductive tract

The reproductive tract of the female dog begins with the ovaries where the ova (or eggs) are produced. When a female puppy is born, every egg that will be released by her ovaries over her lifetime is already present. They are, however, in an immature form and require further development to reach a stage that can be fertilized by sperm. When a dog's heat cycle starts, hormones stimulate the maturation of some of the ova or eggs. The ova are then released through the surface of the ovary and pass into the oviducts. These are tiny tubes that run between the ovaries and the horns of the uterus. It is within the oviducts that fertilization (the union of the sperm cell and ovum) occurs. The horns are the muscular section of the uterus between the oviducts and the body of the uterus. The uterine horns of dogs can vary greatly in length and diameter. In the typical 40-pound dog, they are normally about four inches long and the diameter of a wooden pencil. When the animal is in heat, their thickness will easily double and they may lengthen slightly. During pregnancy, they will vary from 2.5 to 6 inches in diameter and up to 24 inches in length. The horns attach to the body of the uterus, a short common area where the horns meet. The uterus ends at the cervix of the dog. During pregnancy, most puppies develop within the uterine horns, but one may reside within the body of the uterus.

Birth control pills

There are birth control pills and medications manufactured specifically for use in dogs. Most of these oral products can have serious unwanted side effects, are expensive, and usually cannot be used for long periods of time.

Surgical sterilization

Since birth control pills are not a viable option as a practical permanent form of sterilization, the only option is surgical sterilization. In the female, this would be either spaying (medically referred to as ovariohysterectomy); a hysterectomy, in which only the uterus is removed; or a tubal ligation. These are different surgeries, but each one will prevent future pregnancies if done correctly. Only an ovariohysterectomy should be considered for the long-term health of your dog.

Ovariohysterectomy: An ovariohysterectomy (OHE) or spay is the complete removal of the female reproductive tract. The ovaries, oviducts, uterine horns, and the uterus are removed. Not only does this procedure prevent the animal from becoming pregnant, it also eliminates the twice-yearly heat cycles. The surgery removes the source of production of such hormones as estrogen and progesterone. These hormones are responsible for stimulating and controlling heat cycles and play a major role during pregnancy. But they also have other effects on the body and some of them are potentially harmful.

Tubal Ligation or Hysterectomy: A tubal ligation, whether in veterinary or human medicine, only affects the oviducts. These small structures are isolated during surgery and then cut and tied off with suture material. This prevents the ova from coming in contact with sperm cells or passing into the horns of the uterus. In a hysterectomy, the uterus is removed, but the ovaries remain. With either procedure, the hormones that are normally produced by the ovaries continue to be released to the rest of the body. This is fairly important in humans. However, in dogs it is a disadvantage.

Tubal ligations and hysterectomies, through owner demand or veterinary preference, have never been very popular in canine medicine. Some owners see hysterectomy or tubal ligation as a way to sterilize the pet, yet still allow her to experience heat cycles and participate in mating. Because the ovaries remain in the animal, the disadvantages of these procedures are similar to those seen in intact dogs (dogs that have not had surgical sterilization).

Disadvantages of tubal ligation, hysterectomy, or not spaying your dog

An OHE eliminates most, if not all, of the female hormone production. In so doing, the real advantages of this procedure are realized. In human cases, great efforts are undertaken to maintain or restore hormone production in the body, but the same is only rarely true in canine practice. These hormones play key roles in reproduction in the dog. However, they can also have many unwanted side effects.

Estrus: During the heat cycle there are behavior and hygienic problems that develop. Females in heat will actively search out male dogs and may attempt to escape from the house or yard, putting them in the danger of traffic, fights with other animals, etc. Often there is a sudden influx of male dogs around the home and yard. These dogs leave numerous droppings and spray plants and trees with urine in an attempt to mark their new found territory. Owners also need to contend with the vaginal bleeding that typically lasts for 4 to 13 days.

Mammary cancer: Estrogen is one of the primary causes of canine mammary cancer, the most common malignant tumor in dogs. Animals that are spayed prior to one year of age very rarely develop this malignancy. Spaying a dog before her first heat is the best way to significantly reduce the chance your dog will develop mammary cancer. The risk of malignant mammary tumors in dogs spayed prior to their first heat is 0.05%. It is 8% for dog spayed after one heat, and 26% in dogs spayed after their second heat.

Tumors of the reproductive tract: Tumors can occur in the uterus and ovaries. An OHE would, of course, eliminate any possibility of these occurring.

Uterine infections: Many female dogs have problems with a severe uterine disease called pyometra following their heat cycles. With this disorder, a normal three-ounce uterus can weigh ten to fifteen pounds and be filled solely with pus. Undetected, this condition is always fatal. Its treatment requires either the use of expensive hormonal and IV fluid therapy or an extremely difficult and expensive ovariohysterectomy. A normal spay costs between $100 and $200, while one done to correct a pyometra can easily cost $600 to over $1000, depending on complications. The strain on the kidneys or heart in some of these cases may be fatal or cause life long problems, even after the infected uterus has been removed.

False pregnancy: Some bitches fail to routinely go out of their heat cycles correctly causing a condition we call 'false pregnancy.' In these cases, even though the bitch may not have mated with a male dog, her body believes it is pregnant due to some incorrect hormonal stimulations that it is receiving. The dog may just have some abdominal swelling and/or engorgement of the mammary glands, but in some cases, they will even make nests and snuggle with socks or toys against their bodies. These animals often experience no long term serious problems, as the behavior disappears when the circulating hormones return to their appropriate levels. In others, we may see mastitis (infection of the mammary glands), metritis (infection of the uterus), or sometimes these cases develop into full-blown pyometras. We recommend spaying dogs that consistently have false pregnancies.

Hair coat problems: In dogs, hair does not grow continuously as in people, but has a definite growing (anagen) and resting (telogen) phase. Estrogen, which is increased during estrus, retards or inhibits the anagen phase, so more hairs are in the telogen phase. These resting hairs are more easily lost because they are less firmly anchored. As a result, the hair coat on many dogs suffers because of estrogen surges that occur with heat cycles or whelping. Their coats appear thin and the underlying skin is exposed in many areas. It can take two to four months for the hair to return to normal. Additionally, there are a small number of female dogs that never develop a normal hair coat because of the cycling hormones. Their coats are consistently thin over the sides of their bodies and these cases are sometimes confused diagnostically with hypothyroid animals. The only treatment for these dogs is an OHE.

Early spaying

In the United States, most dogs are spayed between 5 and 8 months of age. Many humane shelters and veterinarians are starting to spay female animals at a younger age, even at 2 months. This early spaying does not affect the growth rate, and there are no appreciable differences in skeletal, physical, or behavioral development between those animals spayed early than those spayed at a more traditional age. It must be remembered that younger animals may need different anesthetics and are more prone to hypothermia (lower than normal body temperature) during surgery. As long as procedures are modified to account for these differences, early neutering is very safe. In fact, animals spayed at a younger age often have faster recoveries than those spayed when they are older.

Summary

As can be seen from our discussion, an ovariohysterectomy eliminates many medical and behavioral problems that a tubal ligation does not. In fact, in many dogs, an OHE probably adds years to their lives or at least provides them with a more comfortable, less stressful life. The OHE does its part in pet overpopulation, but you, as the owner of an individual dog, should also view it as a way to increase the length and quality of your pet's life with you.

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