​Sterilization is the most common surgery performed and is considered very safe with a very low chance of complications.  One thing that has not changed over the years is that altered animals versus intact animals live longer.  Altered females outlive intact females by 23% and the male altered animal outlives the intact male by 18%. 

With sterilization, there is a reduction or elimination of reproductive organ cancers.  Uterine disease, pyometra, and other uterine-related infections are eliminated.  If done early enough the possibility of mammary tumors is reduced or eliminated.  For a sterilized male there are several problems with lowered incidence such as enlarged prostate and more.  The reduced breeding behavior includes less desire to roam and less aggression. 

Staying home more lowers the chances of being hit by a car, less urge to mark, less barking, and less mounting. less fighting or injury.   For the females reduced breeding behavior includes less howling, nervousness, mounting, no bleeding,  or heat-related crying. The time for surgery is left to your vet’s discretion although we suggest later than 6 months especially for the males to achieve better bone and muscle development.

Female 
Traditional Spaying - OHE (Ovariohysterectomy)

• Removal: Fallopian tubes, ovaries, and uterus are removed
• Behavior: Elimination of breeding behavior
• Age: 6 months
• Problems:
  • Incontinence
  • Weight gain

In the Absence of Ovaries

• Problems result due to the ovaries not producing the Luteinizing Hormone. 
  • The hypothalamus and pituitary gland overproduce the Luteinizing Hormone in the absence of the ovaries. 
• Problems include:
  • Diabetes
  • Hypothyroidism
  • Aggressive/fearful behavior
  • Cancers
  • Other issues.

      
Ovary Sparing Spaying, i.e. Hysterectomy:

• Removal: Uterus and parts of the fallopian tubes are removed   (ovaries remain intact)
• Behavior: Breeding behavior still intact. Hormones are in production.
• Age: 6 months
• Takes a few minutes longer than the older procedure. 
  • There is research that suggests there are risks to prematurely ending hormone reproduction and suggesting intact animals are healthier.

When the Ovaries Are Left Intact:

• The dog will come into heat and have the possibility of getting any of the sex hormone-related diseases or cancers such as ovarian cancer or mammary tumors.

 
Ovariectomy, i.e. Laparoscopic is more common in Europe, also known as a female gonadectomy:

• Removal: Only the ovaries are removed and the uterus remains intact  
• Behavior: Elimination of Breeding behavior
• Age: 6 months
• Incision: Requires 2-3 small incisions requiring one stitch where the others require 1 larger incision
• Faster recovery because it is less invasive. 
• Less chance of nicking the ureters or the narrow duct (tube) that carries the urine from the kidney to the urinary bladder and is next to the uterus
• Problems: ​
  • ​This surgery is more expensive than a normal spay because of the equipment required.

                         
Tubal Ligation:

• Requires additional training as it is yet to be taught in veterinarian school
• Removal: Nothing is removed. The fallopian tubes are sealed or cut preventing an egg’s fertilization (tubes tied).
• Behavior: Breeding behavior continues.
• Age: 6 mos.
• Problems:
  • It is hard to find a doctor who does this procedure,  and it can cost much more than a Basic spay. 

                                                     
Male – Normal hormonal function continues with either procedure.
Traditional Neuter (Orchiectomy)

• Removal: Removes the testicles. The scrotum remains and shrinks.
• Behavior: Breeding behavior goes away (under 12 months surgery)
• Age: 7-12 months.
• Problems:
  • Age is debatable

Vasectomy

• Removal: Nothing is removed.  The tube (vas deferens) that runs from the testes to the end of the penis is cut and sealed. 
  • Testicles are intact and functional.
• Behavior: Will exhibit breeding behaviors.
• Age: 6 months
• This procedure can also be used on young dogs with fewer complications of castration.
• Sperm is absorbed into the body until no longer produced. 
• Problems:
  • Fertility can continue for up to 6 months after surgery.   
  • This procedure is not commonly taught in veterinary schools. 

Chemical Neuter or Intratesticular Injection: 

• The drug Zeuterin® is injected into each of the testes. 
  • Has the active ingredient, zinc gluconate which causes the testes to shrink but retains similar appearance. 
  • This is a permanent solution.
  • For anyone sensitive about the looks of their male dog, this procedure allows the ‘looks’ to be close to normal. 
  • Scrotal Ulcers or draining tracts are possible. 
• Removal: Nothing is removed. 
• Behavior: Breeding Behavior stops
• Age: 6 months
• Problems: 
  • There is an issue about correctly injecting Zeuterin® because if the liquid falls on the skin it can cause severe skin damage. 
  • Scrotal tenderness and swelling are common. 
  • Chemical sterilization can also be permanent, or it can be temporary according to its directive and application.

Conflicting Sides:
There are studies now about when to sterilize a dog with arguments and studies on both sides of the debate. If you have noticed there are notes about when the ovaries are left and when they are removed. The information is documented. This leaves us with your vet as your authority.

So why is sterilization important?
One of the major reasons is pet overpopulation.  One of the other reasons is to eliminate or significantly reduce the breeding behaviors. 
 
References:
Avery, Dr Alex. “Ovaries Only...which Is the Best Spay Surgery for Your Dog?” Our Pet's Health, Our Pet's Health, 31 Jan. 2021, https://ourpetshealth.com/podcast/ovariectomy.

Dr. Patty Khuly, VMD MBA. “Canine Sterilization.” Embrace Pet Insurance, 26 Mar. 2021, https://www.embracepetinsurance.com/health/canine-sterilization.

DVM, Dr. Debra Primovic -. “Vasectomy in Dogs.” RSS, PetPlace, 22 Aug. 2015, https://www.petplace.com/article/dogs/pet-health/vasectomy-in-dogs/.

JiniJini Patel Thompson is a natural health writer and Lazer Tapping instructor. She began riding at age 2 in Kenya. “New Healthier Procedures for Dog Spaying or Neuter: Listen to Your Horse.” Listen To Your Horse | More Freedom | More Joy | More Horse, 2 July 2016, https://listentoyourhorse.com/new-healthier-procedures-for-female-and-male-dog-spaying.

Mdit. “Sterilization of a Dog (Castration & Ovariectomy).” MDIT, 22 Nov. 2019, https://mydogistop.com/sterilization-of-a-dog-castration-ovariectomy/.

“Spaying and Neutering Your Pets - Surgical Sterilization.” PPHC - Plantation Pet Health Center, 13 Mar. 2019, https://www.plantationpethealthcenter.com/veterinary-surgery/spaying-neutering-pets/.

“Sterilization Free Icons Designed by Freepik.” Flaticon, 20 May 2022, https://www.flaticon.com/free-icon/sterilization_1068494?term=Sterile.