timing ovulation in ewes treated with ovsynch different times of pgf2 αinjection during the breeding season

this study was carried out at sakha animal production research station, during the period from oct., 2009 to sept., 2010. forty rahmani ewes were divided into three treatment groups: the 1st, 2nd and 3rd treatment groups were intramuscularly injected (day 0) with 1 ml gnrh analogue followed by an intramuscular injection with 0.7 ml pgf2α5 (g1), 6 (g2) or 7 (g3) days later. a second dose of 1 ml gnrh analogue was given on day 7 (g1), 8 (g2) or 9 (g3), and artificially insemination of treated doze was carried out 24 h later, while the 4th group represented the control ewes which were allowed for natural mating from 1st to the end of january, the breeding season. results show that one out of 10 ewes (10%) exhibited estrous activity in g1 versus 30% (3 out of 10 ewes) in both g2 and g3. ewes in g1 treatment group showed highest (p