KEY POINTS

Pregnancy

1. The development of an embryo involves fusion of an oocyte and spermatozoon within the oviduct.

2. Extension of the life span of the corpus Iuteum in large domestic species and cats is essential for pregnancy maintenance.

3. The placenta acts as an endocrine organ.

Parturition

1. Fetal cortisol initiates delivery through increased secretion of estrogen and thus prostaglandin F_2α.