The EAZI-Breed CIDR Cattle Insert provides an exogenous source of progesterone during the 7-day administration period to facilitate synchronization of estrus in suckled beef cows, and replacement beef and dairy heifers, advancement of first postpartum estrus in suckled beef cows; advancement of first pubertal estrus in replacement beef heifers; and synchronization of the return to estrus in lactating dairy cows inseminated at the immediately preceding estrus. Each insert contains 1.38 grams of progesterone in molded silicone over a flexible nylon spine. Administer intravaginally using the specially designed applicator (blue for dairy cows, green for beef cows).