The semen factors thought to be most important to fertility are the number, the morphology and the motility of the spermatozoa.

The goals of canine breeding programs are usually to optimize both pregnancy rates and litter size.

Radiology and ultrasonography are useful for evaluating the ovaries, uterine wall, and intrauterine contents; for confirming pregnancy; and for assessing fetal viability.

An accurate history is critical to the evaluation of a female animal suspected to be infertile.

Dystocia, or difficult birth, has an overall prevalence of approximately 5% to 6% of pregnancies in bitches and queens.