When veterinarians discuss the pros and cons of spaying and neutering dogs, the choice is presented as an either/or decision. This isn’t surprising. While an intact dog can always be spayed or neutered later, once these surgeries have been performed they cannot be reversed. But what if a third alternative existed?


In fact, it already does.


Implants containing the drug deslorelin acetate are approved for bringing about “temporary infertility” in male dogs in Australia, New Zealand and Europe but have also successfully been used in females in an off label manner. The implant is about the size of a grain of rice and is placed under the skin. The deslorelin acetate it releases binds to receptors in the body that are normally used by gonadotropin releasing hormone thereby suppressing the production of the reproductive hormones necessary for sperm production in males and normal estrus cycles in females.


According to the manufacturer, a single 4.7 mg implant is effective for 6 months, while the 9.4 mg implant will last for 12 months. In an article for CTV news, Dr. Judith Samson-French, a veterinarian who uses deslorelin acetate implants to help control feral dog populations in Canada’s First Nation communities, says that the drug “has been found to last over a year with no side effects.” If a return to reproduction is desired before the implant runs out, it is often possible to surgically remove it.


In addition to its obvious benefits for managing feral populations, I can see many uses for a product like this in private practice. For example,

  • Anesthesia and surgery is unacceptably risky in a particular patient.
  • The dog’s owner does not want anesthesia/surgery for his or her dog.
  • The owner wants to confirm that neutering will not adversely affect a working dog’s performance before opting for permanent surgery.
  • Reproduction is not desired now but may be in the future.
  • Because deslorelin acetate lowers testosterone levels, it could be useful in treating some types of aggressive behavior.


One downside to the deslorelin acetate implant is that it initially acts as a stimulant to the reproductive system. The Saint Louis Zoo’s website states, “females treated with deslorelin should be considered fertile for three weeks following insertion. Males may remain fertile for 2 or more months, until residual sperm either degenerate or are passed (as following vasectomy).” This shouldn’t be much of an issue with regards to pet dogs, but could be significant when considering using the implant in populations that are more difficult to manage and monitor.


For most dogs and owners, I believe that spay/neuter surgeries are the best way to permanently eliminate the risk of unwanted canine pregnancies and reduce the risk of certain diseases; for example, mammary cancer and uterine infections in females and testicular cancer and benign prostatic hypertrophy in males. However, having the option to temporarily prevent reproduction in dogs would certainly be welcome.


What do you think? Would you consider having your dog implanted with deslorelin acetate? Why would you choose a contraceptive implant over permanent sterilization?


Dr. Jennifer Coates


Image: Vladimir Gjorgiev / Shutterstock