FIELD TRIALS OF ESTRUS SYNCHRONIZATION AN D AL-RESULTS IN AN ARAB BROODMARE HERD IN THE NATIONAL STUD HASIRCI ESKISEHIR (TURKEY)

An Arab broodmare herd of 30 mares age ranging from 4 to 12 years was grouped into 3 groups (group A, B, C) with 1 0 mares each and exposed to three different methods of cycle synchronisation. Group A mares rec eived two PGF2alpha injections 14 days apart. Group B mares got additi onally 2.500 IU of hCG 5 days after second prostaglandinapplication. G roup C consisted of mares which had foaled in a synchrony of one week and got a PGF2alpha injection 3 weeks after parturition. All the mares responding to synchronisation were inseminated closely to ovulation d etected by serial rectal palpations with an insemination dosis of 0.5 billion of progressively motile spermatozoa. Conception control was pe rformed on the 18th day after ovulation to be continued up to pregnanc y confirmation on day 60. Synchronisation response in the different gr oups A, B, C was 60, 80, 80 % starting first oestrus signs between 24 to 36 hours and ovulation time between 5 to 6.5 days post last PGF2alp ha application. Pregnancy rate (first cycle) was 66.7 % (A), 75 % (B) and 87 % (C) basing on the number Of Mares who responded to synchronis ation exposure.