improvement of artificial insemination efficiency in zandi ewes via estradiol and oxytocin injection

the aim followed in the present study was to evaluate the effect of estradiol (e2) injection and injection (either intramuscular (i.m) or intravenous (i.v)) of various doses of oxytocin (ot) on cervix dilation and on conception rate in zandi ewes during late breeding season. sixty three ewes were randomly selected. in experiment 1, the ewes received 100 µl e2 and 12h later were divided and assigned into 7 groups. control group (n=9) did not receive ot. the six remaning groups were divided into 2 parts using i.m or i.v injection and in each group in every part, ewes (n=9) were treated 60, 80 or 100 iu of ot. cervix penetration was measured before and after (10 min and 12h) e2 injection (before ot injection) and 15 min after ot injection by use of a scaled pipette of artificial insemination. experiment 2 was the same as experiment 1 but here the ewes did not receive e2 and were just tested for the effect of ot on cervix dilation. in experiment 3, the estrous synchronization was done using cidr insertion for 12 days. at the time of cidr removal, 500 iu of ecg was injected i.m to the ewes.