Proper ovulation in females and ejaculation of fertile and normal sperm by males are regulated through a sequence of events in the brain, nervous system, and sexual organs. For best results, ovulation and de-position of semen into the female genital tract must be closely synchronized. Failure of any step in either sex leads to infertility or sterility. The ultimate result of infertility is the failure to produce offspring. In females, infertility may be due to improper timing of breeding (the most common cause), the absence of the estrous cycle, abnormal ovulation, failure to conceive, or prenatal death. Major infertility problems in males are caused by disturbances in the production, transport, or storage of sperm; loss of libido (sexual desire); and partial or complete inability to mate. Most major infertility problems are complex. Often, several factors, singly or in combination, can cause failure to produce offspring.

Regardless of whether reproduction is attempted through natural mating or by artificial insemination, your veterinarian will determine whether it is the female or male that is infertile. Infertility can be diagnosed through laboratory tests, semen evaluation, or ultrasonography. Infertility is seldom accompanied by obvious signs of illness or infection. Lower fertility may be hereditary and your veterinarian will consider this issue when treating fertility problems.

In dogs, the focus of treatment is the individual animal. Diagnostic techniques and treatments are becoming more advanced every year. Infertility can be treated by administration of hormones that act directly on the ovaries or regulate their functions, or act to help maintain pregnancy. Hormonal treatment can also work on male dogs with low sperm counts or poor libido. On the other hand, hormonal treatment can also be used for prevention of pregnancy after undesired mating.

Antibiotics are used for treatment of infection of the reproductive tracts. The selection of the antibiotic is based on tests that determine the nature of the bacteria or infectious agent.

In some circumstances, unsatisfactory results with antibiotics and increased concerns about bacteria that develop resistance to a particular antibiotic have led veterinarians to use treatments other than antibiotics for infections of the reproductive tract. These drugs boost local immune defenses and can be used alone or in combination with antibiotics.

Last full review/revision July 2011 by Cheri A. Johnson, DVM, MS, DACVIM (Small Animal); Brad E. Seguin, DVM, MS, PhD DACT; Autumn P. Davidson, DVM, MS, DACVIM; Fabio Del Piero, DVM, DACVP, PhD; James A. Flanders, DVM, DACVS; Mushtaq A. Memon, BVSc, MS, PhD, DACT; Paul Nicoletti, DVM, MS; Robert C. Rosenthal, DVM, PhD, DACVIM (Small Animal, Oncology), DACVR (Radiation Oncology)