Resumo

CATALANO, R; TERUEL, M; CABODEVILA, J  e  CALLEJAS, S. Effect of different doses of equine chorionic gonadotropin on reproductive performance in sheep with oestrus induction treatment cycle. InVet [online]. 2007, vol.9, n.1, pp.11-17. ISSN 1668-3498.

The aim of this study was to evaluate the reproductive performance of seasonally anoestrus hoggets (Trial 1) and ewes (Trial 2) (Frisona x Corriedale) treated with intravaginal sponges containing 60 mg of medroxiprogesterone acetate during 10 days and different doses of eCG. At the end of treatment, 300 IU of eCG (group G300) or 500 IU of eCG (group G500) were injected intramuscularly. Oestrus rate was not different between groups (Trial 1= 100%; Trial 2= 81.2%; P>0.05). In the trial 1, the percentage of hoggets that ovulated tended to differ between groups (G300= 50.0%; G500= 90.0%; P=0.06) and the pregnancy rate was signifi cant different (G300= 20.0%; G500= 70.0%; P<0.05). In the trial 2, the pregnancy and the fertility rates were signifi cant different between groups G300 and G500 (6.3 and 9.1 vs 56.3 and 60.0% respectively; P<0.05). It was concluded that the use of 300 UI of eCG in a treatment of oestrus induction of seasonally anoestrus hoggets and ewes affect negatively the reproductive performance compared with the use of 500 UI of eCG.

Palavras-chave : Ewes; Oestrus induction; ECG; Pregnancy.

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