*5.2.2.1 Techniques of progesterone treatment*


CIDR insert for cattle is made by molding a thin layer of silicon and progesterone mixture (10% w/w) around a nylon spine under high temperature. It contains 1.38 g progesterone and is designed to maintain higher blood concentrations of progesterone to at least 2 ng/ml for up to 10 days. The CIDR is easily inserted into the vagina and has good retention capacity (2.5% loss rate is normal); a flexible nylon tail is attached to it for easy removal. The CIDR provides an exogenous source of the progesterone, and its removal on treatment day 7 results in a rapid fall in plasma progesterone levels, which results in estrus synchronization in those animals responding to treatment.
