Stress, sexual overuse, heat, and temporary injury to sperm-producing cells are potentially reversible and often improve with a period of prolonged sexual rest.
A male of marginal fertility should be bred at the peak of female fertility (72 hours after ovulation), as determined by vaginal cytology and progesterone measurements (see The Estrous Cycle).
Hormone therapy and drugs to correct retrograde ejaculation and immune-mediated orchitis have been of benefit in some cases. Genetic and chromosomal abnormalities associated with intersex may be accompanied by genitalia that appear abnormal. The diagnosis is made by karyotyping (analyzing the number, size, and shape of the paired chromosomes).
Dogs with congenital infertility, and those with acquired infertility who do not produce sperm after six months of treatment, usually do not become fertile.