CIDR is used in reproductive management to deliver progesterone. Which term describes this device?

• A. Nervous tissue
• B. Cardiac
• C. DNA structure
• D. CIDR

Answer: (D)

The main idea here is recognizing what a CIDR is in reproductive management. A CIDR is a vaginal device that releases progesterone over a defined period, helping control and synchronize estrous cycles in livestock. The term describing this device is CIDR, which stands for Controlled Internal Drug Release. After the device is removed, progesterone levels fall, allowing animals to come into estrus in a predictable window, often used in combination with prostaglandins to tighten the synchronization. The other terms—nervous tissue, cardiac, DNA structure—refer to biological components, not a hormone-delivery device, so they don’t describe what CIDR is.