Ovaries were scanned by ultrasonogr

Ovaries were scanned by ultrasonography on Day
10 and cows with CL were blocked by pen and assigned randomly to receive no supplemental progesterone (control, n ¼ 863) or to receive a controlled internal drug-release (CIDR) insert containing progesterone from Days
10 to

3 (1CIDR, n ¼ 862).