BULLETIN OF THE VETERINARY INSTITUTE IN PULAWY, cilt.50, sa.4, ss.497-501, 2006 (SCI-Expanded)
The study aimed to stimulate ovarian cycle and increase conception rates with administration of GnRH prior to the synchronisation of ovulation; by the use of Ovsynch protocol in cows (n=58) with anoestrus. For group I GnRH was administered one week prior to Ovsynch protocol. For group II, only Ovsynch protocol was applied. The synchronisation rate was statistically higher (P < 0.01) in group II (95.2%) than that in group I (71.0%). The conception rate was higher (P < 0.01) in group I (40.0%) than that in group II (20.8%). At the beginning of the Ovsynch protocol, the percentage of cows with progesterone levels higher than I ng/ml,vas 83.3% in group I, and 29.2% in group II, and cycling, rate, based on progesterone levels above 1 ng/ml, was higher in group I (50.0%) than that in group II (20.8%) among cows with body condition score (BCS) >= 2.5. In conclusion, additional GnRH treatment one,week prior to Ovsynch protocol, positively affected the conception rate and ovarian cycling, and this programme Could be used for the treatment of functional anoestrus in cows.