Luteal regression occurred in 96% of cows with a functional CL when treated with PGF2α between d 6
and 18 of the cycle, and in 90% of the cows regression of the CL was accompanied with formation of a new CL.
Ninety-five percent of cows that had luteal regression after treatment with PGF2α exhibited estrus. Eightyone
percent of cows that had a functional CL when treated with PGF2α on d 6 to 18 of the cycle responded
with both estrous behavior and normal concentrations of progesterone in plasma. A similar response was observed
in Holstein heifers (Stevenson et al., 1984; Watts and Fuquay, 1985). Ovulation without estrus occurred