**4. Final comments**

In this chapter, we have discussed that different methods are available for contraception in domestic dogs. Each one has its own advantages and disadvantages, which should be taken into consideration when discussing with the owner the best therapeutic option available for a particular bitch. When selecting the contraceptive treatment(s) to discuss with the owner, it is important to establish the purpose for the treatment (short- or long-term treatments vs. sterilization), the schedule of drug administration and the costs of the therapeutics, as well as the expected length of treatment and the objectives for the female fertility at the end of the treatment. It is also important to ascertain the dog category (ownerless or community vs. owned dog), the compliance of the owner with the schedule and its expectations toward the meaning of "chemical spaying." And, most of all, it is important to be confident that the selected treatment is adequate to the age of female and neither compromise an existing, undiagnosed, pregnancy, nor trigger or aggravate an existing disease.

Nowadays, safer and healthier alternatives to progestins are already available for medical contraception in dogs that are intended to be breed later in their lives. Major drawbacks for the use of progestins include their deleterious effects on the uterus and mammary gland and the possibility of fertility loss after chronic treatments. Bitches over the age of 5 years are poor candidates for progestin treatments. Good alternatives already exist, and should be recommended whenever the costs of the drug do not impose constraints. Most products can be applied independently of the age of the female and are devoid of side effects on the uterus or the mammary gland.

The identification of new safer methods for nonsurgical contraception in dogs, manufactured at a desirable scale to be provided at affordable rates and needing fewer applications (particularly for permanent and the long-term contraception) is still a challenge to the industry. Active research and increased knowledge in this field promises to change the paradigm of canine contraception in the future.
