Synchronization of estrus in Frisian cows with progesterone releasing intravaginal devices and prostaglandins


Twenty-five pure Frisian cows were used to compare three estrus synchrony regimens. First group was synchronized using PRID alone for 14 days. A second group was treated with PRID for 8 days and one injection 15 mg of prostaglandin at 24 hours prior to PRID removal. The third group received two injections of prostaglandins at 11-day interval. Percentages of cows cycling during the synchronization periods of the 3 groups were 66.6% during 72-96 hours after removal of the devices, 90.9% during 48-72 hours after the end of the treatment and 87.5% after 56-96 hours in the first second and third respectively.