The Eazi-Breed CIDR is used to improve the timing and efficiency of cow and heifer breeding programs. Each Eazi-Breed CIDR Cattle Insert contains grams of progesterone. Inserts are administered intravaginally, one per animal, releasing progesterone during the seven-day treatment period. For synchronization of estrus in beef cows, replacement beef and dairy heifers, an injection of Lutalyse must be given one day before insert removal; for lactating dairy cow synchronization administer Lutalyse when insert is removed. Removal of the insert on treatment day seven results in a drop in plasma progesterone, triggering estrus within three days. (Lutalyse is a prescription drug.) Applicator sold separately.