Induction of Synchronized Oestrus in Akkaraman Cross-Bred Ewes Treated with Prostaglandine F2 Alpha, Norgestomet and Sponges Impregnated with Different Doses of Fluorogestene Acetate at the Beginning Transitional Period

Abstract

The efficiency of different progesterone and PGF2 alpha treatments in the induction of ovarian activity and synchronization of oestrus was investigated the beginning transitional period in sheep. A total of 75 ewes were used in the experiment. Animals were divided into 5 groups. Vaginal sponges containing either 30 mg or 40 mg fluorogestene acetate (FGA) were inserted into the vagina of ewes in the first (FGA-30; n=15) and second (FGA-40; n=15) groups, respectively. The sponges were withdrawn after 12 day. In the third group of ewes (n=15), ear implants containing 3 mg norgestomet (N-IMPLANT) were inserted subcutaneously and removed after 9 day. In the fourth group (n=15), Tiaprost tromethamine (PGF2 alpha; 0.294 mg) was intramuscularly injected twice at an interval of 9-d. The control (Control) group is consisted of 15 ewes. After the second PGF2 alpha injections and the withdrawal of the sponges and implants, 600 IU PMSG was injected to all ewes in the FGA-30, FGA-40, N-Implant and PGF2 alpha groups. After the detection of oestrus ewes, they were naturally mated. Oestrus response rates were significantly higher in the groups FGA-30 (93.3%), and N-IMPLANT (93.3%) than those in the groups PGF2 alpha (53.3%) and Control (26.6%). However, oestrus rates in the group FGA-40 were only significantly higher (86.6%) than those in the group Control (26.6%). The pregnancy rates in the groups FGA-30 (93.3%) and N-IMPLANT (93.3%) were significantly higher than that in the group PGF2 alpha (53.3%). No significant difference was observed among the groups FGA-30, FGA-40, N-IMPLANT and PGF2 alpha with respect to lambing rates. Multiple birth rates were significantly higher in the group N-IMPLANT (35.7%) than in the group PGF2 alpha (0.0%). As a conclusion, a double dosed application of PGF2 alpha was observed to be inefficient compared to different progesterone treatments in ewes the beginning transitional period.