The rates of conception/pregnancy obtained after oestrus synchronization in dairy cows with PRID/GnRH and PRID programs.

The aim of this paper was to compare, from the point of view of the synchronization the estrus and the rates of conception and pregnancy, two synchronization programs with PRID and PRID/GnRH. The treatments of synchronization of the estrous and the ovulations were carried out according to the following synchronization protocol: (i) in the interval 46-50 days from calving was administered a dose of 2 ml Proliz (400 mcg Cloprostenol), after 7 days was introduced intravaginal a PRID device with a content of 1.55 g progesterone, after 7 days were administered 400 mcg Cloprostenol and after 2 days were retracted PRID. The females were inseminated at 56 hours from the retraction of PRID; (ii) 400 mcg Cloprostenol in the interval 46-50 days from calving, after 7 days was introduced intravaginally one PRID plus 100 mcg GnRH, after 7 days was administered 400 mcg Cloprostenol, after 2 days were retract PRID and at 32 hours were administered 100 mcg of GnRH. The females were artificially inseminated at 56 hours after the retraction of PRID.