Reproduktivna aktivnost pubertetskih siljezica rase Cigaja posle tretmana sa PMSG ili PMSG+Gn-RH tokom sezone parenja.
1987
Stancic B. | Ivos R. | Vulic Dj.
On the ovaria of sacrificed yearlings treated with progestogen, progestogen + PMSG or progestogen + PMSG + Gn-RH an ovulation value of 1.33, 1.66 and 1.72 has been found. In addition to fresh ovulations and tiny follicles, on the ovaria of the animals treated only with progestogen, no other functional structures (preovular follicles and large follicular cysts) have been found, such as found on the ovaria of the animals treated with PMSG or PMSG + Gn-RH. The treatment with Gn-RH did not considerably prevent the occurence of the mentioned undesirable ovarial structures. Oestrus was detected in 80% of the yearlings treated with progestogen, in 75% of the animals treated with progestogen + PMSG + Gn-RH and in 60% of the yearlings treated with progestogen + PMSG. The lowest rate of the successful conception (35%) has been found in the yearlings treated with progestogen + PMSG, a bit higher (50%) in those treated with progestogen + PMSG + Gn-RH, and the highest in yearlings treated with progestogen only. The average number of lambs ranged from 1.16 (only progestogen) and 1.50 resp. 1.57 by the animals treated hith the combination with PMSG resp. PMSG + Gn-RH. The obtained results indicate the basic conclusion, that the applied dose of PMSG incites the occurrence of a larger number of undesirable ovarial structures (large inovulated follicles into follicular cysts), and that by the addition of Gn-RH it is not possible to prevent considerably these occurrences. Therefore, it seems, it might be more efficient to combine larger doses of PMSG with luteinizing hormone or hormonal substance of a similar physiological effect (for instance HCG). In this regard further investigations of the problem of stimulation of a synchronized ovulation by sheep should be directed toward the application of exogenous gonadotrophic substances.
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