| Abstract: | 49 anoestrous ewes (German Blackface) were treated with 0,1 mg oestradiolvalerianate (OT) during 3 successive days. Intensive follicular development could be observed 24–48 brs. later and 6.5, % of the animals ovulated. HCG (500–700 IU) did not improve the effect on ovulations. Better results were obtained near the end of the anoestrous season. In spite of distinct heat symptoms sexual behaviour was not intact, most of the treated ewes refused the ram. From 84 anoestrous ewes treated by the same method during April, May und July ca. 80 % accepted the ram, 40 % lambed, 20 % conceived during the first heat, 10 % during the second oestrous, 10 % 4–9 weeks after treatment. Only 20 % of the 48 control animals lambed. In maiden-ewes, 6–7 months of age, ovulations without heat could be stimulated by psychological factors (mounting by rams, driving, transport etc.) within 24 hrs. During August 66 % of the immature animals ovulated after treatment with 3 × 0,05 mg OV, but refused the ram. During October all immature animals ovulated following a single injection of 0,05 mg OV and all were mated. The fertilization rate of the eggs was low. |
