Luteal phase manipulation can involve:

• CL regression directly (prostaglandins)
• Maintainence of progesterone until CL naturally regresses (progestins)

Follicular phase manipulation can involve:

• Induction of ovulation or follicle lutinization (GnRH, eCG)
• Stimulation of follicle growth (FSH)

Estrus synchronization schemes often use a series of drugs which allow producers to precisely time insemination.

Review the estrus cycle for the livestock species to understand the different estrus synchronization schemes for the different species.