Research Information System
VETERINARNI MEDICINA, vol.51, no.4, pp.133-138, 2006 (SCI-Expanded)
The efficiency of medroxyprogesterone acetate (MAP) sponges in combination with either pregnant mare serum gonadotrophin (PMSG) or cloprostenol (PGF(2 alpha)) for inducing and synchronizing the estrous cycle in non-lactating Kivircik ewes was investigated during the natural non-breeding season. All ewes (n = 69) were treated with 60 mg MAP sponges for 12 days. In addition, each ewe received an intramuscular injection of either 1.5 ml sterile saline solution (n = 18); 125 mu g PGF(2 alpha) (n = 14); 500 IU PMSG (n = 18) or 500 IU PMSG and 125 mu g PGF2 alpha (n = 19), 48 h before the sponge removal. Cervical artificial insemination (AI) with diluted fresh semen was performed at a fixed time ( 48 and 60 h) following progestagen withdrawal. The different groups estrous response for the first 24 +/- 6 h and within 120 h, time to onset and duration of the induced estrous, and pregnancy rate was found to be 36.2%, 81.6%, 41.7 +/- 2.3 h, 29.6 +/- 1.5 h, and 54.5%, respectively. There were significant differences between groups MAP and MAP/PGF(2 alpha) and their with the two latter groups (MAP/PMSG, MAP/PMSG/PGF(2 alpha)) in terms of the onset of induced estrous (P < 0.05) and between groups MAP and MAP/PGF2a in terms of the duration of induced estrous (P < 0.05) and between the first two groups ( MAP, MAP/PGF2a) and the latter two groups (MAP/PMSG, MAP/PMSG/PGF2 alpha) in terms of estrous response at the first 24 +/- 6 h ( P < 0.05). These results indicate that, the use of MAP/PMSG, rather than MAP or MAP/PGF2 alpha, was effective in the attainment of early and compact induction and synchronization of estrous in non-lactating Kivircik ewes during the natural non-breeding season.