By: Cate Burnette

World Spay Day is February 23

If you’re a pet parent that frequents Facebook or reads Craig’s List or the local want ads, you can’t help but notice the huge numbers of unwanted cats and dogs living and dying in rescues and shelters throughout this country. For years, animal advocates have promoted spaying and neutering of all companion animals as a way to lower the numbers of unwanted pets that die annually on our city streets and in our local shelters.

But have you really looked at the statistics regarding homeless animals…and do you know the health reasons behind the spaying/neutering recommendations of veterinarians and animal rescuers?

Because we are animal lovers and pet parents ourselves, we have gathered this information for you. PLEASE feel free to share this material with your friends and relatives who think that they need puppies or that sterilizing pets is ‘unnatural.’ Your furry companions – and all their homeless cousins – will thank you.

Shelter Facts/Statistics

Because most of the relevant information is based on estimates derived from surveys, and the various survey-takers don’t always agree, obtaining accurate statistical data about pets in the US is not an easy undertaking. What we are left with is a series of statistics that can only approximate the numbers of animals living – and dying – in our shelters and rescues.

The ASPCA states:

  • “Approximately 7.6 million companion animals enter animal shelters nationwide every year. Of those, approximately 3.9 million are dogs and 3.4 million are cats.
  • Each year, approximately 2.7 million animals are euthanized (1.2 million dogs and 1.4 million cats).
  • Approximately 2.7 million shelter animals are adopted each year (1.4 million dogs and 1.3 million cats).
  • About 649,000 animals that enter shelters as strays are returned to their owners. Of those, 542,000 are dogs and only 100,000 are cats.
  • Of the dogs entering shelters, approximately 35% are adopted, 31% are euthanized and 26% of dogs who came in as strays are returned to their owner.
  • Of the cats entering shelters, approximately 37% are adopted, 41% are euthanized, and less than 5% of cats who came in as strays are returned to their owners.
  • About twice as many animals enter shelters as strays compared to the number that are relinquished by their owners.
  • It is impossible to determine how many stray dogs and cats live in the United States; estimates for cats alone range up to 70 million.
  • The average number of litters a fertile cat produces is one to two a year; the average number of kittens is four to six per litter.
  • The average number of litters a fertile dog produces is one a year; the average number of puppies is four to six.
  • Owned cats and dogs generally live longer, healthier lives than strays.
  • Many strays are lost pets that were not kept properly indoors or provided with identification.
  • Only 10% of the animals received by shelters have been spayed or neutered, while 83% of pet dogs and 91% of pet cats are spayed or neutered.”

Most importantly for the purposes of this blog …

  • The cost of spaying or neutering your pet is less than the cost of raising puppies or kittens for a year.

Benefits of Spay/Neuter

Besides the obvious fact that spaying your female pets prevents any unwanted pregnancies, sterilizing your animals can change the unwanted roaming behaviors that occur when females are in heat and males take off to seek them out. Additionally, the procedures can preclude diseases caused by the rise and fall of male and female hormones including mammary cancers and pyometra in females and testicular and prostate cancers in males.

1. According the Ohio State University Veterinary Medical Center, Mammary Cancers are very common in dogs – significantly more widespread in intact females than those dogs that have been spayed before the first heat cycle. Approximately 50 percent of these types of tumors are malignant and can metastasize to other organs – typically the lungs – fairly quickly.

a. The most common Symptom of mammary tumors is a lump or a series of lumps in and/or around the glands on the underside of your dog’s torso. The mass may be freely movable or attached to the skin or body wall. You might notice some inflammation and/or superficial skin loss on the surface of the skin over the mammary tissue.

b. Diagnosis revolves around surgical excision of the tumors and laboratory analysis of the mass looking for malignant cells. Many veterinarians also recommend chest and abdominal radiographs searching for other tumors and possible fine-needle aspirates or surgical removal of lymph nodes if metastasis is suspected.

c. Treatment of this type of cancer is centered on removal of the tumor. As of now, there is no proven positive result of any chemotherapy drugs for the treatment of malignant mammary tumors. Certain drugs for the treatment of carcinomas or sarcomas (gemcitabine, carboplatin, and/or doxorubicin) may be helpful in delaying recurrence or metastases, but their efficacy is unknown and chemotherapy is not commonly used.

d. Prognosis depends on the type of mammary cancer detected and the involvement of other organs. The good news – surgery for tumors that have not spread may be curative. The not-so-good news – average survival rates after surgical removal of the breast or mammary tissue with tubular adenocarcinoma (a malignant tumor without metastasis) is almost 25 months. Small (under 5 centimeters in diameter) malignant tumors have a good prognosis if the removal of surrounding tissue is complete. The bad news – any type of lymph node involvement worsens the prognosis and a full recovery is most likely not possible.

2. Pyometra affects both dogs and cats and typically occurs approximately 2 to 3 weeks after the end of the last heat cycle. The repeated exposure to the hormones estrogen and progesterone, present in your pet’s body in larger quantities during estrus (heat), causes an abnormal thickening of the innermost layer of the uterus. Most common in animals 6 years of age or older, “open” or “closed” pyometras are characterized by pus-filled cysts inside the uterus that are either releasing or holding in inflammatory fluids depending on the open or closed status of the cervix.

a. Symptoms of this condition include an abnormal, painful distention of the abdomen due to the inflamed uterus, vaginal discharge, depression and lethargy, lack of appetite, frequent urination, vomiting and sometimes fever.

b. Veterinary Diagnosis centers on a complete physical exam by your veterinarian, abdominal palpation, bloodwork focusing on the increase of white blood cells present during inflammation, and x-rays and possible ultra-sound procedures looking for pregnancy or infection. Your vet will also want a complete history including the last date of estrus.

c. Treatment is typically immediate surgery for removal of the infected uterus and ovaries. Only animals with high breeding value in terms of monetary importance may be offered other options, commonly a sterile cleaning of the uterus and surrounding areas to remove pus and fluids; however, the average house pet is not that animal. Antibiotics are usually recommended to combat infection and prostaglandins administered to cause the smooth uterine muscles to contract.

d. Prognosis for pyometra is excellent if the disease is caught in time to remove the infected uterus without the organ bursting and flooding the abdominal cavity with pus. Delayed treatment can result in systemic sepsis and possible death. Once the uterus has returned to normal size and there are no signs of continued fluids, your pup will be released home to continue antibiotic treatment and pain management for several weeks.

3. Testicular Cancers make up 90 percent of all cancers that originate from the male reproductive system, say veterinary experts at the National Canine Cancer Foundation. Caused by a retained testicle (cryptorchidism), continuous flooding of testosterone and/or exposure to environmental carcinogens, senior, un-neutered Boxers, German Shepherds, Afghan Hounds, Weimaraners and Shetland Sheepdogs are predisposed to these tumors. Although testicular tumors rarely metastasize, when they do, the cancer has been known to travel to the lymph nodes, liver, kidneys, spleen, adrenal glands, pancreas, lungs and central nervous system.

a. Symptoms of testicular tumors include atrophy of the “normal” testicle, feminization, loss of hair around the site, darkening of the testicular skin, development of abnormally large mammary glands in males, atrophy of the penis and a pendulous enlargement of the skin sac (the prepuce) that covers the penis. You might also notice blood in your dog’s urine, a swollen, twisted testicle, and fluid in the abdomen.

b. Diagnosis by your veterinarian requires rectal palpation feeling for tumors, ultrasonography of the testicles and abdomen, a fine-needle aspirate of any tumors and complete blood count looking for resulting blood abnormalities including a reduction in white blood cells and platelet numbers.

c. Treatment is typically surgical removal of both testes. Since these tumors tend to be localized, systemic chemotherapy and radiation is rarely used unless blood testing shows irregularities.

d. Prognosis for dogs treated with surgery is good. However, those animals showing blood abnormalities present a guarded prognosis, achieving an average survival time of 5 to 31 months after chemotherapy treatment.

4. Prostate Cancers are commonly malignant tumors that rapidly metastasize to the lungs, bones, and lymph nodes of un-neutered and sterilized, senior, large-breed dogs. Although the exact cause of prostate cancer is unknown, hormonal imbalances of testosterone are suggested as a possible cause.

a. Symptoms of prostate cancer include weight loss and poor appetite, difficulty in passing urine or a complete urine blockage, ribbon-shaped stool, fever, breathing difficulties and lower abdominal pain.

b. Diagnosis is determined by a complete veterinary physical exam, including blood and urine tests. The urine is examined for the presence of malignant cells, white blood cells and infection. Abdominal x-rays and ultrasonography along with a biopsy of the tumor will verify a positive diagnosis.

c. Treatment of prostate cancer typically does not include the difficult removal of the gland due to its close proximity to the urethra (the tube that removes urine from the body). Radiotherapy and chemotherapy may increase the survival time of affected dogs when conducted and supervised by a veterinary oncologist.

d. Prognosis, even with chemo and radiation, is guarded and revolves around administering chemotherapeutic drugs at home and observing your dog to ensure that adequate urination and defecation can be maintained. The inability to urinate and defecate properly is often accompanied by severe pain and restlessness, and you may need to give pain medications to keep your dog comfortable.

Possible Disadvantages of Early Spay/Neuter

Unlike most pets in the US, the overwhelming majority of dogs and cats in Europe are not neutered before one year of age or the first heat cycle. Many European veterinarians believe that early neutering and the removal of growth hormones can adversely affect multiple organ systems in some dogs.

A recent study funded by the Canine Health Foundation and the Center for Companion Animal Health at the University of California, Davis may add some weight to this theory.

According to the research, 759 client-owned Golden Retrievers were examined for diagnosis of hip dysplasia, cranial cruciate ligament tear, lymphosarcoma, hemangiosarcoma, and mast cell tumors. Patients were classified as intact, neutered early (before 12 months of age) or neutered late (at or later than 12 months of age).

Of early-neutered males, 10 percent were diagnosed with hip dysplasia, double the occurrence in intact males. There were no cases of cruciate ligament issues diagnosed in intact males or females, but in early-neutered males and females the occurrences were 5 percent and 8 percent, respectively. Almost 10 percent of early-neutered males were diagnosed with lymphosarcoma, 3 times more than intact males. The percentage of hemangiosarcoma cases in late-neutered females (about 8 percent) was 4 times more than intact and early-neutered females. There were no cases of mast cell tumors in intact females, but the occurrence was nearly 6 percent in late-neutered females.

As of this writing, the American Veterinary Medical Association continues to advocate for early spay/neutering.

Please consult with your veterinarian about the best spaying/neutering options for you and your pet.


Cate Burnette is a semi-retired registered veterinary technician with clinical experience in small and large animal medicine. With 30-plus years of journalism experience, she went back to school after 9/11 to work with her first love: animals. The pet parent of four cats, three dogs and one ex-racehorse, Cate is a certified rescue volunteer with the American Humane Association’s Red Star Emergency Services and served with the group in New Orleans doing animal search and rescue after Hurricane Katrina. She is also a horse safety and horse management expert, and has volunteered with US Pony Clubs as a district commissioner and horse management judge.

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