The paper describes comperatively aspects of oogenesis and folliculogenesis
, oocyte and follicular growth in cattle and pigs. Moreover, gonadotropin d
ependent regulatory processes of the wave like pattern of follicular growth
are discussed in both species as well as functional and morphological chan
ges during oocyte maturation. Finally, time dependent processes after occur
rence of spontaneous or GnRH induced LH surge are discussed.