Efficacy of CIDR or FGA Sponges with hCG Treatments on the Conception Rate and Prolificacyin Lori Ewes Out of the Breeding Season

Two experiments were performed to determine the effectiveness of different progestogens contained in intravaginal devices, different doses of eCG and subsequent hCG treatment on the reproductive performance of estrus-induced mature Lori ewes. In the first experiment, 88 ewes were allocated into two groups, and were treated with either fluorogestone acetate (FGA) sponges or Controlled Internal Drug Release devices (CIDR).The sponges were withdrawn 13 days after insertion and then ewes were treated with either 350 IU or 500 IU of eCG by intramuscular injection. There was no significant difference among treatments in the percentage of ewes in estrus or the interval to the onset of estrus. However, the conception rate and prolificacy of ewes treated with 350 IU eCG, in both the FGA and CIDR groups, was higher than ewes treated with 500 IU of eCG. In the second experiment 384 ewes were randomly divided into three groups and after synchronization with FGA spongesand 350 IU of eCG, 128 ewes in the first group (T1) were injected 250 IU hCG when artificially inseminated, 128 ewes in the second group (T2) were injected 250 IU hCG 12 days after AI and the 128 ewes in the third group (C) acted as the control group. Estrous was determined by monitoring 35 teaser rams to calculate estrous rate. Prolificacy and conception rate were assessed and serum progesterone (P4) concentrations were measured on days 12, 14 and 16 days after AI. Prolificacy was increased in the T1 group compared with control group (P